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Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 72d218235f
commit f23f22d71c
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---
from: http://rosettacode.org/wiki/Extensible_prime_generator
note: Prime Numbers

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;Task:
Write a generator of prime numbers, in order, that will automatically adjust to accommodate the generation of any reasonably high prime.
The routine should demonstrably rely on either:
# Being based on an open-ended counter set to count without upper limit other than system or programming language limits. In this case, explain where this counter is in the code.
# Being based on a limit that is extended automatically. In this case, choose a small limit that ensures the limit will be passed when generating some of the values to be asked for below.
# If other methods of creating an extensible prime generator are used, the algorithm's means of extensibility/lack of limits should be stated.
The routine should be used to:
* Show the first twenty primes.
* Show the primes between 100 and 150.
* Show the ''number'' of primes between 7,700 and 8,000.
* Show the 10,000th prime.
<br>
Show output on this page.
'''Note:''' You may reference code already on this site if it is written to be imported/included, then only the code necessary for import and the performance of this task need be shown. (It is also important to leave a forward link on the referenced tasks entry so that later editors know that the code is used for multiple tasks).
'''Note 2:''' If a languages in-built prime generator is extensible or is guaranteed to generate primes up to a system limit, (2<sup>31</sup> or memory overflow for example), then this may be used as long as an explanation of the limits of the prime generator is also given. (Which may include a link to/excerpt from, language documentation).
'''Note 3:'''The task is written so it may be useful in solving the task &nbsp; [[Emirp primes]] &nbsp; as well as others (depending on its efficiency).
<br>
<br>
;Reference:
* [http://www.primos.mat.br/indexen.html Prime Numbers]. Website with large count of primes.
<br><br>

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with Ada.Text_IO, Miller_Rabin;
procedure Prime_Gen is
type Num is range 0 .. 2**63-1; -- maximum for the gnat Ada compiler
MR_Iterations: constant Positive := 25;
-- the probability Pr[Is_Prime(N, MR_Iterations) = Probably_Prime]
-- is 1 for prime N and < 4**(-MR_Iterations) for composed N
function Next(P: Num) return Num is
N: Num := P+1;
package MR is new Miller_Rabin(Num); use MR;
begin
while not (Is_Prime(N, MR_Iterations) = Probably_Prime) loop
N := N + 1;
end loop;
return N;
end Next;
Current: Num;
Count: Num := 0;
begin
-- show the first twenty primes
Ada.Text_IO.Put("First 20 primes:");
Current := 1;
for I in 1 .. 20 loop
Current := Next(Current);
Ada.Text_IO.Put(Num'Image(Current));
end loop;
Ada.Text_IO.New_Line;
-- show the primes between 100 and 150
Ada.Text_IO.Put("Primes between 100 and 150:");
Current := 99;
loop
Current := Next(Current);
exit when Current > 150;
Ada.Text_IO.Put(Num'Image(Current));
end loop;
Ada.Text_IO.New_Line;
-- count primes between 7700 and 8000
Ada.Text_IO.Put("Number of primes between 7700 and 8000:");
Current := 7699;
loop
Current := Next(Current);
exit when Current > 8000;
Count := Count + 1;
end loop;
Ada.Text_IO.Put_Line(Num'Image(Count));
Count := 10;
Ada.Text_IO.Put_Line("Print the K_i'th prime, for $K=10**i:");
begin
loop
Current := 1;
for I in 1 .. Count loop
Current := Next(Current);
end loop;
Ada.Text_IO.Put(Num'Image(Count) & "th prime:" &
Num'Image(Current));
Count := Count * 10;
end loop;
exception
when Constraint_Error =>
Ada.Text_IO.Put_Line(" can't compute the" & Num'Image(Count) &
"th prime:");
end;
end;

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SetBatchLines, -1
p := 1 ;p functions as the counter
Loop, 10000 {
p := NextPrime(p)
if (A_Index < 21)
a .= p ", "
if (p < 151 && p > 99)
b .= p ", "
if (p < 8001 && p > 7699)
c++
}
MsgBox, % "First twenty primes: " RTrim(a, ", ")
. "`nPrimes between 100 and 150: " RTrim(b, ", ")
. "`nNumber of primes between 7,700 and 8,000: " RTrim(c, ", ")
. "`nThe 10,000th prime: " p
NextPrime(n) {
Loop
if (IsPrime(++n))
return n
}
IsPrime(n) {
if (n < 2)
return, 0
else if (n < 4)
return, 1
else if (!Mod(n, 2))
return, 0
else if (n < 9)
return 1
else if (!Mod(n, 3))
return, 0
else {
r := Floor(Sqrt(n))
f := 5
while (f <= r) {
if (!Mod(n, f))
return, 0
if (!Mod(n, (f + 2)))
return, 0
f += 6
}
return, 1
}
}

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# Function that returns a new prime generator
PrimeGen {𝕤
i 0 # Counter: index of next prime to be output
primes 0
next 2
Sieve { p 𝕊 in:
E {(((𝕩|-i)+𝕩×))n-i} # Indices of multiples of 𝕩
i + / (1˜n-i) E{0¨(𝕨)𝕩}´ p # Primes in segment [i,n)
}
{𝕤
{ i=primes ? # Extend if required
next ((224)+ ט) oldnext # Sieve at most 16M new entries
primes (primes()next) Sieve oldnext
;@}
(i+1) iprimes
}
}
_w_{𝔽𝔾𝔽_𝕣_𝔾𝔽𝔾𝕩} # Looping utility for the session below

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pg PrimeGen@
(function block)
PG¨ 20
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71
{p0 PG{ p𝕩}_w_(< 150) PG _w_(< 100)0 p}
101 103 107 109 113 127 131 137 139 149
{p0 PG{𝕤p+1}_w_(<8000) PG _w_(<7700)0 p}
30
(PrimeGen@)1e4 @ # Reset the count with a new generator
104729

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#include <iostream>
#include <cstdint>
#include <queue>
#include <utility>
#include <vector>
#include <limits>
template<typename integer>
class prime_generator {
public:
integer next_prime();
integer count() const {
return count_;
}
private:
struct queue_item {
queue_item(integer prime, integer multiple, unsigned int wheel_index) :
prime_(prime), multiple_(multiple), wheel_index_(wheel_index) {}
integer prime_;
integer multiple_;
unsigned int wheel_index_;
};
struct cmp {
bool operator()(const queue_item& a, const queue_item& b) const {
return a.multiple_ > b.multiple_;
}
};
static integer wheel_next(unsigned int& index) {
integer offset = wheel_[index];
++index;
if (index == std::size(wheel_))
index = 0;
return offset;
}
typedef std::priority_queue<queue_item, std::vector<queue_item>, cmp> queue;
integer next_ = 11;
integer count_ = 0;
queue queue_;
unsigned int wheel_index_ = 0;
static const unsigned int wheel_[];
static const integer primes_[];
};
template<typename integer>
const unsigned int prime_generator<integer>::wheel_[] = {
2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6, 2, 6, 4, 2,
6, 4, 6, 8, 4, 2, 4, 2, 4, 8, 6, 4, 6, 2, 4, 6,
2, 6, 6, 4, 2, 4, 6, 2, 6, 4, 2, 4, 2, 10, 2, 10
};
template<typename integer>
const integer prime_generator<integer>::primes_[] = {
2, 3, 5, 7
};
template<typename integer>
integer prime_generator<integer>::next_prime() {
if (count_ < std::size(primes_))
return primes_[count_++];
integer n = next_;
integer prev = 0;
while (!queue_.empty()) {
queue_item item = queue_.top();
if (prev != 0 && prev != item.multiple_)
n += wheel_next(wheel_index_);
if (item.multiple_ > n)
break;
else if (item.multiple_ == n) {
queue_.pop();
queue_item new_item(item);
new_item.multiple_ += new_item.prime_ * wheel_next(new_item.wheel_index_);
queue_.push(new_item);
}
else
throw std::overflow_error("prime_generator: overflow!");
prev = item.multiple_;
}
if (std::numeric_limits<integer>::max()/n > n)
queue_.emplace(n, n * n, wheel_index_);
next_ = n + wheel_next(wheel_index_);
++count_;
return n;
}
int main() {
typedef uint32_t integer;
prime_generator<integer> pgen;
std::cout << "First 20 primes:\n";
for (int i = 0; i < 20; ++i) {
integer p = pgen.next_prime();
if (i != 0)
std::cout << ", ";
std::cout << p;
}
std::cout << "\nPrimes between 100 and 150:\n";
for (int n = 0; ; ) {
integer p = pgen.next_prime();
if (p > 150)
break;
if (p >= 100) {
if (n != 0)
std::cout << ", ";
std::cout << p;
++n;
}
}
int count = 0;
for (;;) {
integer p = pgen.next_prime();
if (p > 8000)
break;
if (p >= 7700)
++count;
}
std::cout << "\nNumber of primes between 7700 and 8000: " << count << '\n';
for (integer n = 10000; n <= 10000000; n *= 10) {
integer prime;
while (pgen.count() != n)
prime = pgen.next_prime();
std::cout << n << "th prime: " << prime << '\n';
}
return 0;
}

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#include <algorithm>
#include <iostream>
#include <cmath>
#include <cstdint>
#include <vector>
#include <limits>
template<typename integer>
class prime_generator {
public:
explicit prime_generator(integer initial_limit = 100, integer increment = 100000);
integer next_prime();
integer count() const {
return count_;
}
private:
void find_primes(integer);
integer count_ = 0;
integer limit_;
integer index_ = 0;
integer increment_;
std::vector<integer> primes_;
std::vector<bool> sieve_;
integer sieve_limit_ = 0;
};
template<typename integer>
integer next_odd_number(integer n) {
return n % 2 == 0 ? n + 1 : n;
}
template<typename integer>
prime_generator<integer>::prime_generator(integer initial_limit, integer increment)
: limit_(next_odd_number(initial_limit)), increment_(increment) {
primes_.push_back(2);
find_primes(3);
}
template<typename integer>
integer prime_generator<integer>::next_prime() {
if (index_ == primes_.size()) {
if (std::numeric_limits<integer>::max() - increment_ < limit_)
return 0;
int start = limit_ + 2;
limit_ = next_odd_number(limit_ + increment_);
primes_.clear();
find_primes(start);
}
++count_;
return primes_[index_++];
}
template<typename integer>
integer isqrt(integer n) {
return next_odd_number(static_cast<integer>(std::sqrt(n)));
}
template<typename integer>
void prime_generator<integer>::find_primes(integer start) {
index_ = 0;
integer new_limit = isqrt(limit_);
sieve_.resize(new_limit/2);
for (integer p = 3; p * p <= new_limit; p += 2) {
if (sieve_[p/2 - 1])
continue;
integer q = p * std::max(p, next_odd_number((sieve_limit_ + p - 1)/p));
for (; q <= new_limit; q += 2*p)
sieve_[q/2 - 1] = true;
}
sieve_limit_ = new_limit;
size_t count = (limit_ - start)/2 + 1;
std::vector<bool> composite(count, false);
for (integer p = 3; p <= new_limit; p += 2) {
if (sieve_[p/2 - 1])
continue;
integer q = p * std::max(p, next_odd_number((start + p - 1)/p)) - start;
q /= 2;
for (; q < count; q += p)
composite[q] = true;
}
for (integer p = 0; p < count; ++p) {
if (!composite[p])
primes_.push_back(p * 2 + start);
}
}
int main() {
typedef uint64_t integer;
prime_generator<integer> pgen(100, 500000);
std::cout << "First 20 primes:\n";
for (int i = 0; i < 20; ++i) {
integer p = pgen.next_prime();
if (i != 0)
std::cout << ", ";
std::cout << p;
}
std::cout << "\nPrimes between 100 and 150:\n";
for (int n = 0; ; ) {
integer p = pgen.next_prime();
if (p > 150)
break;
if (p >= 100) {
if (n != 0)
std::cout << ", ";
std::cout << p;
++n;
}
}
int count = 0;
for (;;) {
integer p = pgen.next_prime();
if (p > 8000)
break;
if (p >= 7700)
++count;
}
std::cout << "\nNumber of primes between 7700 and 8000: " << count << '\n';
for (integer n = 10000; n <= 100000000; n *= 10) {
integer prime;
while (pgen.count() != n)
prime = pgen.next_prime();
std::cout << n << "th prime: " << prime << '\n';
}
return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define CHUNK_BYTES (32 << 8)
#define CHUNK_SIZE (CHUNK_BYTES << 6)
int field[CHUNK_BYTES];
#define GET(x) (field[(x)>>6] & 1<<((x)>>1&31))
#define SET(x) (field[(x)>>6] |= 1<<((x)>>1&31))
typedef unsigned uint;
typedef struct {
uint *e;
uint cap, len;
} uarray;
uarray primes, offset;
void push(uarray *a, uint n)
{
if (a->len >= a->cap) {
if (!(a->cap *= 2)) a->cap = 16;
a->e = realloc(a->e, sizeof(uint) * a->cap);
}
a->e[a->len++] = n;
}
uint low;
void init(void)
{
uint p, q;
unsigned char f[1<<16];
memset(f, 0, sizeof(f));
push(&primes, 2);
push(&offset, 0);
for (p = 3; p < 1<<16; p += 2) {
if (f[p]) continue;
for (q = p*p; q < 1<<16; q += 2*p) f[q] = 1;
push(&primes, p);
push(&offset, q);
}
low = 1<<16;
}
void sieve(void)
{
uint i, p, q, hi, ptop;
if (!low) init();
memset(field, 0, sizeof(field));
hi = low + CHUNK_SIZE;
ptop = sqrt(hi) * 2 + 1;
for (i = 1; (p = primes.e[i]*2) < ptop; i++) {
for (q = offset.e[i] - low; q < CHUNK_SIZE; q += p)
SET(q);
offset.e[i] = q + low;
}
for (p = 1; p < CHUNK_SIZE; p += 2)
if (!GET(p)) push(&primes, low + p);
low = hi;
}
int main(void)
{
uint i, p, c;
while (primes.len < 20) sieve();
printf("First 20:");
for (i = 0; i < 20; i++)
printf(" %u", primes.e[i]);
putchar('\n');
while (primes.e[primes.len-1] < 150) sieve();
printf("Between 100 and 150:");
for (i = 0; i < primes.len; i++) {
if ((p = primes.e[i]) >= 100 && p < 150)
printf(" %u", primes.e[i]);
}
putchar('\n');
while (primes.e[primes.len-1] < 8000) sieve();
for (i = c = 0; i < primes.len; i++)
if ((p = primes.e[i]) >= 7700 && p < 8000) c++;
printf("%u primes between 7700 and 8000\n", c);
for (c = 10; c <= 100000000; c *= 10) {
while (primes.len < c) sieve();
printf("%uth prime: %u\n", c, primes.e[c-1]);
}
return 0;
}

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#include <stdio.h>
#include <stdlib.h>
#include "pairheap.h"
int wheel2357[48] = {
10, 2, 4, 2, 4, 6, 2, 6,
4, 2, 4, 6, 6, 2, 6, 4,
2, 6, 4, 6, 8, 4, 2, 4,
2, 4, 8, 6, 4, 6, 2, 4,
6, 2, 6, 6, 4, 2, 4, 6,
2, 6, 4, 2, 4, 2, 10, 2,
};
typedef struct { // elements in the priority queue
pq_node_t hd;
int offset; // index to skip value in 2,3,5,7 wheel
long int base_prime;
} w2357_multiples;
typedef struct {
int start_ndx;
int offset;
long int candidate;
heap_t composites;
int count; // count of primes returned.
} primegen_t;
primegen_t make_pgen() {
w2357_multiples *composites;
primegen_t gen;
gen.start_ndx = 0; // primes 2, 3, 5, 7, 11
NEW_PQ_ELE(composites, 121);
gen.offset = composites->offset = 1;
gen.candidate = composites->base_prime = 11;
gen.composites = (heap_t) composites;
gen.count = 0;
return gen;
}
long int next_prime(primegen_t *gen) {
static short upto11[] = {
2, 3, 5, 7, 11
};
if (gen->start_ndx < 5) {
++gen->count;
return upto11[gen->start_ndx++];
} else {
for (;;) {
// advance to the next prime candidate.
gen->candidate += wheel2357[gen->offset++];
if (gen->offset == 48)
gen->offset = 0;
// See if the composite number on top of the heap matches
// the candidate.
//
w2357_multiples *top = (w2357_multiples *) gen->composites;
if (top->hd.key == gen->candidate) { // not prime
do {
// advance the top of heap to the next prime multiple
// that is not a multiple of 2, 3, 5, 7.
//
gen->composites = heap_pop(gen->composites);
top->hd.next = top->hd.down = NULL;
top->hd.key += top->base_prime * wheel2357[top->offset++];
if (top->offset == 48)
top->offset = 0;
gen->composites = heap_merge((heap_t) top, gen->composites);
top = (w2357_multiples *) gen->composites;
} while (top->hd.key == gen->candidate);
} else {
// prime found, add the square and it's position on the wheel
// to the heap.
//
w2357_multiples *new;
HEAP_PUSH(
new,
gen->candidate * gen->candidate,
&gen->composites);
new->offset = gen->offset;
new->base_prime = gen->candidate;
++gen->count;
return gen->candidate;
}
}
}
}
int main() {
primegen_t primes = make_pgen();
printf("first 20: ");
for (int i = 1; i <= 20; i++)
printf("%ld ", next_prime(&primes));
putchar('\n');
printf("between 100 and 150: ");
long int p = next_prime(&primes);
while (p < 150) {
if (p > 100)
printf("%ld ", p);
p = next_prime(&primes);
}
putchar('\n');
int count = 0;
while (p < 8000) {
if (p > 7700)
++count;
p = next_prime(&primes);
}
printf("%d primes between 7700 and 8000.\n", count);
long c;
for (c = 10000; c <= 10000000; c *= 10) {
while (primes.count < c)
p = next_prime(&primes);
printf("%ldth prime is %ld\n", c, p);
}
return 0;
}

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ns test-project-intellij.core
(:gen-class)
(:require [clojure.string :as string]))
(def primes
" The following routine produces a infinite sequence of primes
(i.e. can be infinite since the evaluation is lazy in that it
only produces values as needed). The method is from clojure primes.clj library
which produces primes based upon O'Neill's paper:
'The Genuine Sieve of Eratosthenes'.
Produces primes based upon trial division on previously found primes up to
(sqrt number), and uses 'wheel' to avoid
testing numbers which are divisors of 2, 3, 5, or 7.
A full explanation of the method is available at:
[https://github.com/stuarthalloway/programming-clojure/pull/12] "
(concat
[2 3 5 7]
(lazy-seq
(let [primes-from ; generates primes by only checking if primes
; numbers which are not divisible by 2, 3, 5, or 7
(fn primes-from [n [f & r]]
(if (some #(zero? (rem n %))
(take-while #(<= (* % %) n) primes))
(recur (+ n f) r)
(lazy-seq (cons n (primes-from (+ n f) r)))))
; wheel provides offsets from previous number to insure we are not landing on a divisor of 2, 3, 5, 7
wheel (cycle [2 4 2 4 6 2 6 4 2 4 6 6 2 6 4 2
6 4 6 8 4 2 4 2 4 8 6 4 6 2 4 6
2 6 6 4 2 4 6 2 6 4 2 4 2 10 2 10])]
(primes-from 11 wheel)))))
(defn between [lo hi]
"Primes between lo and hi value "
(->> (take-while #(<= % hi) primes)
(filter #(>= % lo))
))
(println "First twenty:" (take 20 primes))
(println "Between 100 and 150:" (between 100 150))
(println "Number between 7,7700 and 8,000:" (count (between 7700 8000)))
(println "10,000th prime:" (nth primes (dec 10000))) ; decrement by one since nth starts counting from 0
}

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(deftype CIS [v cont]
clojure.lang.ISeq
(first [_] v)
(next [_] (if (nil? cont) nil (cont)))
(more [this] (let [nv (.next this)] (if (nil? nv) (CIS. nil nil) nv)))
(cons [this o] (clojure.core/cons o this))
(empty [_] (if (and (nil? v) (nil? cont)) nil (CIS. nil nil)))
(equiv [this o] (loop [cis1 this, cis2 o] (if (nil? cis1) (if (nil? cis2) true false)
(if (or (not= (type cis1) (type cis2))
(not= (.v cis1) (.v ^CIS cis2))
(and (nil? (.cont cis1))
(not (nil? (.cont ^CIS cis2))))
(and (nil? (.cont ^CIS cis2))
(not (nil? (.cont cis1))))) false
(if (nil? (.cont cis1)) true
(recur ((.cont cis1)) ((.cont ^CIS cis2))))))))
(count [this] (loop [cis this, cnt 0] (if (or (nil? cis) (nil? (.cont cis))) cnt
(recur ((.cont cis)) (inc cnt)))))
clojure.lang.Seqable
(seq [this] (if (and (nil? v) (nil? cont)) nil this))
clojure.lang.Sequential
Object
(toString [this] (if (and (nil? v) (nil? cont)) "()" (.toString (seq (map identity this))))))
(comment " the wheel could also be a pre-determined vector as for the 2/3/5/7 wheel below...
(def wheel
[ 2 4 2 4 6 2 6 4 2 4 6 6 2 6 4 2
6 4 6 8 4 2 4 2 4 8 6 4 6 2 4 6
2 6 6 4 2 4 6 2 6 4 2 4 2 10 2 10 ])
")
(def wheel-primes [2 3 5 7 11 13 17])
(def next-prime 19)
(def nextnext-prime 23)
;; calculates the vector for very large wheels such as the 92160 element version here
;; the disadvantage is that it takes some time to calculate before the work can start...
(def wheel
(loop [p 2, len 1, ^bytes ptrn [1]]
(if (>= p next-prime)
ptrn
(let [cptrn (cycle ptrn), [f & rcyc] cptrn,
np (+ p f), nlen (* len (- p 1)),
culls
(map (fn [[f _]] f)
(iterate (fn [[c [g & r]]] [(+ c (* p g)) r]) [(* p p) cptrn])),
gaps (drop 1
(for [[gp _ _ _ cnt]
(iterate (fn [[_ v cls [g & rgs] c]]
(let [[cl & rcls] cls, tv (+ v g),
[sg & srgs] rgs, nc (+ c 1)]
(if (= cl tv)
[(+ g sg) (+ tv sg) rcls srgs nc]
[g tv cls rgs nc])))
[f np culls rcyc 0]) :while (<= cnt nlen)] gp))]
(recur np nlen (vec gaps))))))
(def wheellmt (- (count wheel) 1))
(defn primes-treeFolding
"Computes the unbounded sequence of primes using a Sieve of Eratosthenes algorithm modified from Bird."
[]
(letfn [(mltpls [[p pi]]
(letfn [(nxtmltpl [c ci]
(let [nci (if (< ci wheellmt) (+ ci 1) 0)]
(->CIS c #(-> (nxtmltpl (+ c (* p (get wheel ci))) nci)))))]
(nxtmltpl (* p p) pi))),
(allmtpls [^CIS pxs]
(->CIS (mltpls (.v pxs)) #(-> (allmtpls ((.cont pxs)))))),
(union [^CIS xs ^CIS ys]
(let [xv (.v xs), yv (.v ys)]
(if (< xv yv) (->CIS xv #(-> (union ((.cont xs)) ys)))
(if (< yv xv)
(->CIS yv #(-> (union xs ((.cont ys)))))
(->CIS xv #(-> (union (next xs) ((.cont ys))))))))),
(pairs [^CIS mltplss] (let [^CIS tl ((.cont mltplss))]
(->CIS (union (.v mltplss) (.v tl))
#(-> (pairs ((.cont tl))))))),
(mrgmltpls [^CIS mltplss]
(->CIS (.v ^CIS (.v mltplss))
#(-> (union ((.cont ^CIS (.v mltplss)))
(mrgmltpls (pairs ((.cont mltplss)))))))),
(minusStrtAt [n ni ^CIS cmpsts]
(let [nn (+ n (get wheel ni)), nni (if (< ni wheellmt) (+ ni 1) 0)]
(if (< n (.v cmpsts))
(->CIS [n ni] #(-> (minusStrtAt nn nni cmpsts)))
(recur nn nni ((.cont cmpsts)))))),
(xtraprmsndxd []
(->CIS [next-prime 0] #(-> (minusStrtAt nextnext-prime 1
(mrgmltpls (allmtpls (xtraprmsndxd))))))),
(stripndxs [^CIS ndxd]
(->CIS (get (.v ndxd) 0) #(-> (stripndxs ((.cont ndxd))))))]
(loop [i (- (count wheel-primes) 1), ff (fn [] (stripndxs (xtraprmsndxd)))]
(if (<= i 0)
(->CIS (get wheel-primes 0) ff)
(recur (- i 1) (fn [] (->CIS (get wheel-primes i) ff)))))))

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@ -0,0 +1,36 @@
primes = () ->
yield 2
yield 3
sieve = ([] for i in [1..3])
sieve[0].push 3
[r, s] = [3, 9]
pos = 1
n = 5
loop
isPrime = true
if sieve[pos].length > 0 # this entry has a list of factors
isPrime = false
sieve[(pos + m) % sieve.length].push m for m in sieve[pos]
sieve[pos] = []
if n is s # n is the next square
if isPrime
isPrime = false # r divides n, so not actually prime
sieve[(pos + r) % sieve.length].push r # however, r is prime
r += 2
s = r*r
yield n if isPrime
n += 2
pos += 1
if pos is sieve.length
sieve.push [] # array size must exceed largest prime found
sieve.push [] # adding two entries keeps size = O(sqrt n)
pos = 0
undefined # prevent CoffeeScript from aggregating values
module.exports = {
primes
}

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@ -0,0 +1,26 @@
primes = require('sieve').primes
gen = primes()
console.log "The first 20 primes: #{gen.next().value for _ in [1..20]}"
p100_150 = (while (p = gen.next().value) < 150 then p).filter (n) -> n > 100
console.log "The primes between 100 and 150: #{p100_150}"
while gen.next().value < 7700
undefined
count = 1
while gen.next().value < 8000
++count
console.log "There are #{count} primes between 7,700 and 8,000."
n = 10
c = 0
gen = primes()
loop
p = gen.next().value
c += 1
if c is n
console.log "The #{n}th prime is #{p}"
break if n is 10_000_000
n *= 10

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@ -0,0 +1,12 @@
void main() {
import std.stdio, std.range, std.algorithm, sieve_of_eratosthenes3;
Prime prime;
writeln("First twenty primes:\n", 20.iota.map!prime);
writeln("Primes primes between 100 and 150:\n",
uint.max.iota.map!prime.until!q{a > 150}.filter!q{a > 99});
writeln("Number of primes between 7,700 and 8,000: ",
uint.max.iota.map!prime.until!q{a > 8_000}
.filter!q{a > 7_699}.walkLength);
writeln("10,000th prime: ", prime(9_999));
}

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/// Prime sieve based on: http://www.cs.hmc.edu/~oneill/papers/Sieve-JFP.pdf
import std.container: Array, BinaryHeap, RedBlackTree;
struct LazyPrimeSieve {
@property bool empty() const pure nothrow @safe @nogc {
return i > 203_280_221; // Pi(2 ^^ 32).
}
@property auto front() const pure nothrow @safe @nogc {
return prime;
}
@property void popFront() pure nothrow /*@safe*/ {
prime = sieveOne();
}
private:
static struct Wheel2357 {
static immutable ubyte[48] holes = [2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6,
2, 6, 4, 2, 6, 4, 6, 8, 4, 2, 4, 2, 4, 8, 6, 4, 6, 2, 4, 6, 2, 6, 6,
4, 2, 4, 6, 2, 6, 4, 2, 4, 2, 10, 2, 10];
static immutable ubyte[4] spokes = [2, 3, 5, 7];
static immutable ubyte first = 11;
uint i;
auto spin() pure nothrow @safe @nogc {
return holes[i++ % $];
}
}
static struct CompositeIterator {
uint prime;
Wheel2357 wheel;
ulong composite;
this(uint p) pure nothrow @safe @nogc {
prime = p;
composite = p * wheel.first;
}
void next() pure nothrow @safe @nogc {
composite += prime * wheel.spin;
}
}
version (heap) // Less memory but slower.
BinaryHeap!(Array!CompositeIterator, "a.composite > b.composite") iterators;
else // Faster but is more GC intensive.
RedBlackTree!(CompositeIterator, "a.composite < b.composite", true) iterators;
uint prime = 2;
uint i = 1;
Wheel2357 wheel;
uint candidate = wheel.first;
uint sieveOne() pure nothrow /*@safe*/ {
switch (i) {
case 0: .. case wheel.spokes.length - 1:
return wheel.spokes[i++];
case wheel.spokes.length:
i++;
return candidate;
case wheel.spokes.length + 1:
version (heap) {}
else
iterators = new typeof(iterators);
goto default;
default:
goto POST_RETURN;
while (true) {
candidate += wheel.spin;
while (iterators.front.composite < candidate) {
auto it = iterators.front;
iterators.removeFront;
it.next;
iterators.insert(it);
}
if (iterators.front.composite != candidate) {
i++;
return candidate;
POST_RETURN:
// Only insert primes that are multiply
// occuring in [0, 2 ^^ 32).
if (candidate < 2 ^^ 16)
iterators.insert(CompositeIterator(candidate));
}
}
}
}
}
void main() /*@safe*/ {
import std.stdio, std.algorithm, std.range;
writeln("Sum of first 100,000 primes: ", LazyPrimeSieve().take(100_000).sum(0uL));
writeln("First twenty primes:\n", LazyPrimeSieve().take(20));
writeln("Primes primes between 100 and 150:\n",
LazyPrimeSieve().until!q{a > 150}.filter!q{a > 99});
writeln("Number of primes between 7,700 and 8,000: ",
LazyPrimeSieve().until!q{a > 8_000}.filter!q{a > 7_699}.walkLength);
writeln("10,000th prime: ", LazyPrimeSieve().dropExactly(9999).front);
}

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@ -0,0 +1,50 @@
Iterable<int> primesMap() {
Iterable<int> oddprms() sync* {
yield(3); yield(5); // need at least 2 for initialization
final Map<int, int> bpmap = {9: 6};
final Iterator<int> bps = oddprms().iterator;
bps.moveNext(); bps.moveNext(); // skip past 3 to 5
int bp = bps.current;
int n = bp;
int q = bp * bp;
while (true) {
n += 2;
while (n >= q || bpmap.containsKey(n)) {
if (n >= q) {
final int inc = bp << 1;
bpmap[bp * bp + inc] = inc;
bps.moveNext(); bp = bps.current; q = bp * bp;
} else {
final int inc = bpmap.remove(n);
int next = n + inc;
while (bpmap.containsKey(next)) {
next += inc;
}
bpmap[next] = inc;
}
n += 2;
}
yield(n);
}
}
return [2].followedBy(oddprms());
}
void main() {
print("The first 20 primes:");
String str = "( ";
primesMap().take(20).forEach((p)=>str += "$p "); print(str + ")");
print("Primes between 100 and 150:");
str = "( ";
primesMap().skipWhile((p)=>p<100).takeWhile((p)=>p<150)
.forEach((p)=>str += "$p "); print(str + ")");
print("Number of primes between 7700 and 8000: ${
primesMap().skipWhile((p)=>p<7700).takeWhile((p)=>p<8000).length
}");
print("The 10,000th prime: ${
primesMap().skip(9999).first
}");
final start = DateTime.now().millisecondsSinceEpoch;
final answer = primesMap().takeWhile((p)=>p<2000000).reduce((a,p)=>a+p);
final elapsed = DateTime.now().millisecondsSinceEpoch - start;
}

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@ -0,0 +1,307 @@
{{-------- Declaration for BitBoolean Array ------------------}
{Bit boolean - because it stores 8 bools per bytye, it will}
{handle up to 16 gigabyte in a 32 bit programming environment}
type TBitBoolArray = class(TObject)
private
FSize: int64;
ByteArray: array of Byte;
function GetValue(Index: int64): boolean;
procedure WriteValue(Index: int64; const Value: boolean);
function GetSize: int64;
procedure SetSize(const Value: int64);
protected
public
property Value[Index: int64]: boolean read GetValue write WriteValue; default;
constructor Create;
property Count: int64 read GetSize write SetSize;
procedure Clear(Value: boolean);
end;
{------------------------------------------------------------}
{ Implementation for Bitboolean array -----------------------}
{------------------------------------------------------------}
{ TBitBoolArray }
const BitArray: array [0..7] of byte = ($01, $02, $04, $08, $10, $20, $40, $80);
function TBitBoolArray.GetValue(Index: int64): boolean;
begin
{Note: (Index and 7) is faster than (Index mod 8)}
Result:=(ByteArray[Index shr 3] and BitArray[Index and 7])<>0;
end;
procedure TBitBoolArray.WriteValue(Index: int64; const Value: boolean);
var Inx: int64;
begin
Inx:=Index shr 3;
{Note: (Index and 7) is faster than (Index mod 8)}
if Value then ByteArray[Inx]:=ByteArray[Inx] or BitArray[Index and 7]
else ByteArray[Inx]:=ByteArray[Inx] and not BitArray[Index and 7]
end;
constructor TBitBoolArray.Create;
begin
SetLength(ByteArray,0);
end;
function TBitBoolArray.GetSize: int64;
begin
Result:=FSize;
end;
procedure TBitBoolArray.SetSize(const Value: int64);
var Len: int64;
begin
FSize:=Value;
{Storing 8 items per byte}
Len:=Value div 8;
{We need one more to fill partial bits}
if (Value mod 8)<>0 then Inc(Len);
SetLength(ByteArray,Len);
end;
procedure TBitBoolArray.Clear(Value: boolean);
var Fill: byte;
begin
if Value then Fill:=$FF else Fill:=0;
FillChar(ByteArray[0],Length(ByteArray),Fill);
end;
{========== TPrimeSieve =======================================================}
{Sieve object the generates and holds prime values}
{Enable this flag if you need primes past 2 billion.
The flag signals the code to use bit-booleans arrays
which can contain up to 8 x 4 gigabytes = 32 gig booleans.}
// {$define BITBOOL}
type TPrimeSieve = class(TObject)
private
{$ifdef BITBOOL}
PrimeArray: TBitBoolArray;
{$else}
PrimeArray: array of boolean;
{$endif}
FArraySize: int64;
FPrimeCount: int64;
function GetPrime(Index: int64): boolean;
procedure Clear;
function GetCount: int64;
procedure BuildPrimeTable;
protected
procedure DoSieve;
property ArraySize: int64 read FArraySize;
public
Primes: TIntegerDynArray;
BitBoolean: boolean;
constructor Create;
destructor Destroy; override;
procedure Intialize(Size: int64);
property Flags[Index: int64]: boolean read GetPrime; default;
function NextPrime(Start: int64): int64;
function PreviousPrime(Start: int64): int64;
property Count: int64 read GetCount;
property PrimeCount: int64 read FPrimeCount;
end;
procedure TPrimeSieve.Clear;
begin
{$ifdef BITBOOL}
PrimeArray.Clear(True);
{$else}
FillChar(PrimeArray[0],Length(PrimeArray),True);
{$endif}
end;
constructor TPrimeSieve.Create;
begin
{$ifdef BITBOOL}
PrimeArray:=TBitBoolArray.Create;
BitBoolean:=True;
{$else}
BitBoolean:=False;
{$endif}
end;
destructor TPrimeSieve.Destroy;
begin
{$ifdef BITBOOL}
PrimeArray.Free;
{$endif}
inherited;
end;
procedure TPrimeSieve.BuildPrimeTable;
{This builds a table of primes which is}
{easier to use than a table of flags}
var I,Inx: integer;
begin
SetLength(Primes,Self.PrimeCount);
Inx:=0;
for I:=0 to Self.Count-1 do
if Flags[I] then
begin
Primes[Inx]:=I;
Inc(Inx);
end;
end;
procedure TPrimeSieve.DoSieve;
{Load flags with true/false to flag that number is prime}
{Note: does not store even values, because except for 2, all primes are even}
{Starts storing flags at Index=3, so reading/writing routines compensate}
{Uses for-loops for boolean arrays and while-loops for Bit-Booleans arrays}
{$ifdef BITBOOL}
var Offset, I, K: int64;
{$else}
var Offset, I, K: cardinal;
{$endif}
begin
Clear;
{Compensate from primes 1,2 & 3, which aren't stored}
FPrimeCount:=ArraySize+3;
{$ifdef BITBOOL}
I:=0;
while I<ArraySize do
{$else}
for I:=0 to ArraySize-1 do
{$endif}
begin
if PrimeArray[I] then
begin
Offset:= I + I + 3;
K:= I + Offset;
while K <=(ArraySize-1) do
begin
if PrimeArray[K] then Dec(FPrimeCount);
PrimeArray[K]:= False;
K:= K + Offset;
end;
end;
{$ifdef BITBOOL} Inc(I); {$endif}
end;
BuildPrimeTable;
end;
function TPrimeSieve.GetPrime(Index: int64): boolean;
{Get a prime flag from array - compensates}
{ for 0,1,2 and even numbers not being stored}
begin
if Index = 1 then Result:=False
else if Index = 2 then Result:=True
else if (Index and 1)=0 then Result:=false
else Result:=PrimeArray[(Index div 2)-1];
end;
function TPrimeSieve.NextPrime(Start: int64): int64;
{Get next prime after Start}
begin
Result:=Start+1;
while Result<=((ArraySize-1) * 2) do
begin
if Self.Flags[Result] then break;
Inc(Result);
end;
end;
function TPrimeSieve.PreviousPrime(Start: int64): int64;
{Get Previous prime Before Start}
begin
Result:=Start-1;
while Result>0 do
begin
if Self.Flags[Result] then break;
Dec(Result);
end;
end;
procedure TPrimeSieve.Intialize(Size: int64);
{Set array size and do Sieve to load flag array with}
begin
FArraySize:=Size div 2;
{$ifdef BITBOOL}
PrimeArray.Count:=FArraySize;
{$else}
SetLength(PrimeArray,FArraySize);
{$endif}
DoSieve;
end;
function TPrimeSieve.GetCount: int64;
begin
Result:=FArraySize * 2;
end;
{===========================================================}
procedure ExtensiblePrimeGenerator(Memo: TMemo);
var I,Cnt: integer;
var Sieve: TPrimeSieve;
var S: string;
begin
Sieve:=TPrimeSieve.Create;
try
{Build a table with 1-million primes}
Sieve.Intialize(1000000);
Memo.Lines.Add('Showing the first twenty primes');
S:='';
for I:=0 to 20-1 do
S:=S+' '+IntToStr(Sieve.Primes[I]);
Memo.Lines.Add(S);
Memo.Lines.Add('');
Memo.Lines.Add('Showing the primes between 100 and 150.');
S:='';
for I:=100 to 150 do
if Sieve.Flags[I] then S:=S+' '+IntToStr(I);
Memo.Lines.Add(S);
Memo.Lines.Add('');
Memo.Lines.Add('Showing the number of primes between 7,700 and 8,000.');
Cnt:=0;
for I:=7700 to 8000 do
if Sieve.Flags[I] then Inc(Cnt);
Memo.Lines.Add('Count = '+IntToStr(Cnt));
Memo.Lines.Add('');
Memo.Lines.Add('Showing the 10,000th prime.');
Memo.Lines.Add('10,000th Prime = '+IntToStr(Sieve.Primes[10000-1]));
finally Sieve.Free; end;
end;

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@ -0,0 +1,35 @@
; the first twenty primes
(primes 20)
→ { 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 }
; a stream to generate primes from a
(define (primes-from a)
(let ((p (next-prime a)))
(stream-cons p (primes-from p))))
; primes between 100,150
(for/list ((p (primes-from 100))) #:break (> p 150) p)
→ (101 103 107 109 113 127 131 137 139 149)
; the built-in function (primes-pi )counts the number of primes < a
; count in [7700 ... 8000]
(- (primes-pi 8000) (primes-pi 7700) → 30
; nth-prime
(nth-prime 10000) → 104729
;; big ones
(lib 'bigint)
(define (p-digits n)
(printf "(next-prime %d ! ) has %d digits" n
(number-length (next-prime (factorial n )))))
(next-prime 0! ) has 1 digits
(next-prime 10! ) has 7 digits
(next-prime 100! ) has 158 digits
(next-prime 200! ) has 375 digits
(next-prime 300! ) has 615 digits
(next-prime 400! ) has 869 digits ;; 9400 msec (FireFox)
; is prime (1 + 116!) ?
(prime? (1+ (factorial 116))) → #t

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@ -0,0 +1,63 @@
defmodule PrimesSoEMap do
@typep stt :: {integer, integer, integer, Enumerable.integer, %{integer => integer}}
@spec advance(stt) :: stt
defp advance {n, bp, q, bps?, map} do
bps = if bps? === nil do Stream.drop(oddprms(), 1) else bps? end
nn = n + 2
if nn >= q do
inc = bp + bp
nbps = bps |> Stream.drop(1)
[nbp] = nbps |> Enum.take(1)
advance {nn, nbp, nbp * nbp, nbps, map |> Map.put(nn + inc, inc)}
else if Map.has_key?(map, nn) do
{inc, rmap} = Map.pop(map, nn)
[next] =
Stream.iterate(nn + inc, &(&1 + inc))
|> Stream.drop_while(&(Map.has_key?(rmap, &1))) |> Enum.take(1)
advance {nn, bp, q, bps, Map.put(rmap, next, inc)}
else
{nn, bp, q, bps, map}
end end
end
@spec oddprms() :: Enumerable.integer
defp oddprms do # put first base prime cull seq in Map so never empty
# advance base odd primes to 5 when initialized
init = {7, 5, 25, nil, %{9 => 6}}
[3, 5] # to avoid race, preseed with the first 2 elements...
|> Stream.concat(
Stream.iterate(init, &(advance &1))
|> Stream.map(fn {p,_,_,_,_} -> p end))
end
@spec primes() :: Enumerable.integer
def primes do
Stream.concat([2], oddprms())
end
end
IO.write "The first 20 primes are:\n( "
PrimesSoEMap.primes() |> Stream.take(20) |> Enum.each(&(IO.write "#{&1} "))
IO.puts ")"
IO.write "The primes between 100 to 150 are:\n( "
PrimesSoEMap.primes() |> Stream.drop_while(&(&1<100))
|> Stream.take_while(&(&1<150)) |> Enum.each(&(IO.write "#{&1} "))
IO.puts ")"
IO.write "The number of primes between 7700 and 8000 is: "
PrimesSoEMap.primes() |> Stream.drop_while(&(&1<7700))
|> Stream.take_while(&(&1<8000)) |> Enum.count |> IO.puts
IO.write "The 10,000th prime is: "
PrimesSoEMap.primes() |> Stream.drop(9999)
|> Enum.take(1) |> List.first |>IO.puts
IO.write "The sum of all the priems to two million is: "
testfunc =
fn () ->
ans =
PrimesSoEMap.primes() |> Stream.take_while(&(&1<=2000000))
|> Enum.sum() |> IO.puts
ans end
:timer.tc(testfunc)
|> (fn {t,_} ->
IO.puts "This test bench took #{t} microseconds." end).()

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@ -0,0 +1,7 @@
let primeZ fN =primes()|>Seq.unfold(fun g-> Some(fN(g()), g))
let primesI() =primeZ bigint
let primes64() =primeZ int64
let primes32() =primeZ int32
let pCache =Seq.cache(primes32())
let isPrime g=if g<2 then false else let mx=int(sqrt(float g)) in pCache|>Seq.takeWhile(fun n->n<=mx)|>Seq.forall(fun n->g%n>0)
let isPrime64 g=if g<2L then false else let mx=int(sqrt(float g)) in pCache|>Seq.takeWhile(fun n->n<=mx)|>Seq.forall(fun n->g%(int64 n)>0L)

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@ -0,0 +1 @@
Seq.take 20 primes32()|> Seq.iter (fun n-> printf "%d " n)

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@ -0,0 +1 @@
primes32() |> Seq.skipWhile (fun n->n<100) |> Seq.takeWhile (fun n->n<=150) |> Seq.iter (fun n -> printf "%d " n)

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@ -0,0 +1 @@
printfn "%d" (primes32() |> Seq.skipWhile (fun n->n<7700) |> Seq.takeWhile (fun n->n<=8000) |> Seq.length)

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@ -0,0 +1 @@
Seq.item 9999 pCache

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@ -0,0 +1 @@
Seq.item 10000 pCache

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@ -0,0 +1,6 @@
let strt = System.DateTime.Now.Ticks
for i = 1 to 8 do
let n = pown 10 i // the item index below is zero based!
printfn "The %dth prime is: %A" n (primeZ int |> Seq.item (n - 1))
let timed = (System.DateTime.Now.Ticks - strt) / 10000L
printfn "All of the last took %d milliseconds." timed

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@ -0,0 +1,16 @@
printfn "The first 20 primes are: %s"
( primesSeq() |> Seq.take 20
|> Seq.fold (fun s p -> s + string p + " ") "" )
printfn "The primes from 100 to 150 are: %s"
( primesSeq() |> Seq.skipWhile ((>) (prime 100))
|> Seq.takeWhile ((>=) (prime 150))
|> Seq.fold (fun s p -> s + string p + " ") "" )
printfn "The number of primes from 7700 to 8000 are: %d"
( primesSeq() |> Seq.skipWhile ((>) (prime 7700))
|> Seq.takeWhile ((>=) (prime 8000)) |> Seq.length )
let strt = System.DateTime.Now.Ticks
for i = 1 to 8 do
let n = pown 10 i // the item index below is zero based!
printfn "The %dth prime is: %A" n (primesSeq() |> Seq.item (n - 1))
let timed = (System.DateTime.Now.Ticks - strt) / 10000L
printfn "All of the last took %d milliseconds." timed

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@ -0,0 +1,13 @@
USING: io math.primes prettyprint sequences ;
"First 20 primes: " write
20 nprimes .
"Primes between 100 and 150: " write
100 150 primes-between .
"Number of primes between 7,700 and 8,000: " write
7,700 8,000 primes-between length .
"10,000th prime: " write
10,000 nprimes last .

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@ -0,0 +1,4 @@
DO WHILE(F*F <= LST) !But, F*F might overflow the integer limit so instead,
DO WHILE(F <= LST/F) !Except, LST might also overflow the integer limit, so
DO WHILE(F <= (IST + 2*(SBITS - 1))/F) !Which becomes...
DO WHILE(F <= IST/F + (MOD(IST,F) + 2*(SBITS - 1))/F) !Preserving the remainder from IST/F.

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@ -0,0 +1,398 @@
MODULE PRIMEBAG !Need prime numbers? Plenty are available.
C Creates and expands a disc file for a sieve of Eratoshenes, representing odd numbers only and starting with three.
C Storage requirements: an array of N prime numbers in 16/32/64 bits vs. a bit array up to the 16/32/64 bit limit.
C Word size N Prime N words in bits Bit array in bits.
C 8 bit P(31) = 127 248 128
C P(54) = 251 432 256
C 16 bit P(3,512) = 32,749 56,192 32,768
C P(6,542) = 65,521 104,672 65,536
C 32 bit P(105,097,565) = 2,147,483,647 3,363,122,080 2,147,483,648
C P(203,280,221) = 4,294,967,291 6,504,967,072 4,294,967,296
C 64 bit 2.112E17 ? 1.352E19 9,223,372,036,854,775,808 ~ 9.22E18
C from n/Ln(n) 4.158E17 ? 2.661E19 18,446,744,073,709,551,616 ~ 1.84E19
INTEGER MSG !I/O unit number.
INTEGER SSTASH !For attachment to my stash file.
INTEGER SRECLEN,SCHARS,SBITS !Sizes.
INTEGER SORG !Where the sieve starts. This must be three.
INTEGER SLAST !Last record in my stash file.
DATA SSTASH,SREC,SLAST/0,0,0/ !Prepared by PRIMEBAG.
PARAMETER (SRECLEN = 1024) !4K disc bloc size, but RECL (in OPEN) is in terms of four-byte integers.
PARAMETER (SCHARS = (SRECLEN - 1)*4) !Reserving space for one number at the start.
PARAMETER (SBITS = SCHARS*8) !Known size of a character.
PARAMETER (SORG = 3) !First odd number past two, which is not odd.
CHARACTER*(*) SFILE !A name is needed.
PARAMETER (SFILE = "C:/Nicky/RosettaCode/Primes/PrimeSieve.bit") !I don't have to count the characters.
Components of a buffered record for the stash.
INTEGER SREC !The record number.
CHARACTER*1 C4(4) !The start of the record - a counter.
CHARACTER*1 SCHAR(0:SCHARS - 1) !The majority of the record - a bit array, packed in 8-bit blobs...
Collect some bit twiddling assistants for AND and OR, rather than bit shifting.
CHARACTER*1 BITON(0:7),BITOFF(0:7) !Functions IBSET and IBCLR may not be available, and are little-endian anyway.
PARAMETER (BITON =(/CHAR(2#10000000),CHAR(2#01000000), !128, 64, Reading strictly left-to-right.
1 CHAR(2#00100000),CHAR(2#00010000), ! 32, 16, Uncompromising bigendery.
1 CHAR(2#00001000),CHAR(2#00000100), ! 8, 4, Not just for bytes in words,
3 CHAR(2#00000010),CHAR(2#00000001)/)) ! 2, 1. But also bits in bytes.
PARAMETER (BITOFF=(/CHAR(2#01111111),CHAR(2#10111111), !127, 191, BITON + BITOFF = 255.
2 CHAR(2#11011111),CHAR(2#11101111), !223, 239,
1 CHAR(2#11110111),CHAR(2#11111011), !247, 251,
3 CHAR(2#11111101),CHAR(2#11111110)/)) !253, 254.
CONTAINS
INTEGER FUNCTION I4UNPACK(C4) !Convert four successive characters into an integer.
CHARACTER*1 C4(4) !The characters.
I4UNPACK = ((ICHAR(C4(1))*256 + ICHAR(C4(2)))*256 !Convert the first four bytes
1 + ICHAR(C4(3)))*256 + ICHAR(C4(4)) !To a four-byte integer.
END FUNCTION I4UNPACK !Big-endian style, irrespective of cpu endianness.
SUBROUTINE C4PACK(I4) !Convert an integer into successive bytes.
Could return the result via a fancy function, but for now a global variable will do.
INTEGER I4,N !The integer, and a copy to damage.
INTEGER I !A stepper.
N = I4 !Keep the original safe.
DO I = 4,1,-1 !Know that four characters will do. Fixed format makes this easy.
C4(I) = CHAR(MOD(N,256)) !Grab the low-order eight bits.
N = N/256 !And shift right eight.
END DO !Do it again.
END SUBROUTINE C4PACK !Stored big-endianly, irrespective of cpu endianness.
LOGICAL FUNCTION GRASPPRIMEBAG(F)
INTEGER F !The I/O unit number to use.
LOGICAL EXIST !Use the keyword as a name
INTEGER IOSTAT !And don't worry over assignment direction.
CHARACTER*3 STYLE !One way or another.
SSTASH = F !I shall use it.
INQUIRE (FILE = SFILE,EXIST = EXIST) !Trouble with a missing "path" may arise.
IF (EXIST) THEN !If the file exists,
STYLE = "OLD" !I shall read it.
ELSE !But if it doesn't,
STYLE = "NEW" !I shall create it.
END IF !Enough prevarication.
OPEN(SSTASH,FILE = SFILE, STATUS = STYLE, !Go for the file.
& ACCESS = "DIRECT", RECL = SRECLEN, FORM = "UNFORMATTED", !I have plans.
& ERR = 666, IOSTAT = IOSTAT) !Which may be thwarted.
IF (EXIST) THEN !If there is one...
CALL READSCHAR(1) !The first record is also a header.
SLAST = I4UNPACK(C4) !The number of records stored.
ELSE !Otherwise, start from scratch.
SLAST = 0 !No saved records.
CALL PSURGE(SCHAR) !During preparation of the first batch of bits.
END IF !All should now be in readiness.
GRASPPRIMEBAG = .TRUE.!So, feel confidence.
RETURN !And escape.
666 WRITE (*,667) IOSTAT,SFILE !But, something may have gone wrong.
667 FORMAT ("Pox! Error code ",I0, !A "hole" in the directory path?
1 " when attempting to open file ",A) !Read-only access allowed when I want "update"?
GRASPPRIMEBAG = .FALSE. !Whatever, it didn't work.
END FUNCTION GRASPPRIMEBAG !So much for that.
SUBROUTINE READSCHAR(R) !Get record R into SCHAR, which may already hold it.
INTEGER R !The record number desired.
IF (R.EQ.SREC) RETURN !Perhaps it is already to hand.
SREC = R !If not, move attention to it.
READ (SSTASH,REC = SREC) C4,SCHAR !And read the record.
END SUBROUTINE READSCHAR!Thus, I have a buffer too.
LOGICAL FUNCTION PSURGE(BIT8) !Add another record to the stash.
C Surges forward into the next batch of primes, to be stored via a bit array in the file.
C Each record starts with a count of the number of primes that have gone before.
C Except that for the first record, this is the record counter for the stash file.
C Except that when starting the second record, one is also the number of primes before SORG.
CHARACTER*1 BIT8(0:SCHARS - 1) !Watch out! This may be SCHAR itself!
INTEGER IST,LST !The numbers spanned by the surge.
INTEGER F !A factor.
INTEGER I !Another factor and a stepper.
INTEGER C !Index for array BIT8.
INTEGER NP !Number of primes.
Carry forward the count of previous primes to start the following record..
10 IF (SLAST.GT.0) THEN !Is there a previous record?
CALL READSCHAR(SLAST) !Yes. Grab it. A good chance this is already in C4,SCHAR.
NP = I4UNPACK(C4) !Its count of the primes accumulated before it.
DO I = 0,SCHARS - 1 !Find out how namy primes it fingered by scanning its bits.
NP = NP + COUNT(IAND(ICHAR(SCHAR(I)),ICHAR(BITON)).NE.0) !Whee! Eight at a go!
END DO !On to the next byte.
END IF !When creating a new record, its follower may not be sought in this run.
Concoct the next batch of bits. Contorted calculations avoid integer overflow.
20 BIT8 = CHAR(255) !All bits are aligned with numbers that might prove to be prime.
IST = SORG + SLAST*(2*SBITS) !Bit(0) of BIT8(0) corresponds to IST.
LST = IST + 2*(SBITS - 1) !Bit(last) to this number. Remember, only odd numbers have bits.
IF (IST.LE.0) THEN !Humm. I'd better check.
WRITE (MSG,21) SLAST,IST,LST !This works only with two's complement integers.
21 FORMAT (/,"Integer overflow in the sieve of Eratosthenes!", !Oh dear.
1 /,"Advancing from surge ",I0," to span ",I0," to ",I0) !These numbers will look odd.
PSURGE = .FALSE. !But it is better than no indication of what went wrong.
RETURN !Give in.
END IF !Enough worrying.
F = 3 !The first possible factor. Zapping will start at F²
c DO WHILE(F.LE.LST/F) !If F² is past the end, so will be still larger F: enough.
DO WHILE(F.LE.IST/F + (MOD(IST,F) + 2*(SBITS - 1))/F) !"Synthetic division" avoiding overflow.
I = (IST - 1)/F + 1 !I want the first multiple of F in IST:LST. F may be a factor of IST.
IF (MOD(I,2).EQ.0) I = I + 1!If even, advance to the next odd multiple. Even numbers are omitted by design.
IF (I.LT.F) I = F !Less than F is superfluous: the position was zapped by earlier action.
c I = (I*F - IST)/2 !Current bit positions are for IST, IST+2, IST+4, etc.
I = ((I - IST/F)*F - MOD(IST,F))/2 !Avoids overflow when calculating the start value, I*F.
DO I = I,SBITS - 1,F !Zap every F'th bit along. This is the sieve of Eratosthenes.
C = I/8 !Eight bits per character.
BIT8(C) = CHAR(IAND(ICHAR(BIT8(C)), !For F = 3 and 5, characters will be hit more than once.
1 ICHAR(BITOFF(MOD(I,8))))) !Whack a bit. All the above just for this!
END DO !On to the next bit.
22 F = NEXTPRIME(F) !So much for F. Next, please.
END DO !Are we there yet?
Correct the count in the header, if this is an added record.
30 IF (SLAST.GT.0) THEN !So, was there a pre-existing header record?
CALL READSCHAR(1) !Yes. Get the header record into C4,SCHAR.
CALL C4PACK(SLAST + 1) !This is the new record count.
WRITE (SSTASH,REC = 1) C4,SCHAR !Write it all back.
SCHAR = BIT8 !Ensure that SCHAR and SREC will be agreed.
END IF !So much for the header's count.
Cast the bits into the stash by writing record SLAST + 1..
40 IF (SLAST.EQ.0) THEN !If we're writing the first record,
CALL C4PACK(1) !Then this is the record count.
ELSE !Otherwise,
CALL C4PACK(NP) !Place the previous primes count.
END IF !All this to help PRIME(i).
SLAST = SLAST + 1 !This is now the last stashed record.
WRITE (SSTASH,REC = SLAST) C4,BIT8 !I/O directly from the work area?
SREC = SLAST !This is where BIT8 was written.
PSURGE = .TRUE. !That assumes BIT8 is not SCHAR for SLAST > 1.
END FUNCTION PSURGE !That was fun!
RECURSIVE SUBROUTINE GETSREC(R) !Make present the bit array belonging to record R.
INTEGER R !The record number..
CHARACTER*1 BIT8(0:SCHARS - 1) !A scratchpad. Others may be relying on SCHAR.
IF (SLAST.LE.0) RETURN!DANGER! The first record is being initialised!
DO WHILE(SLAST.LT.R) !If we haven't reached so far,
IF (.NOT.PSURGE(BIT8)) THEN !Slog forwards one record's worth.
WRITE (MSG,1) R !Or maybe not.
1 FORMAT ("Cannot prepare surge ",I0) !Explain.
STOP "No bits, no go." !And quit.
END IF !And having prepared the next block of bits,
END DO !Check afresh.
CALL READSCHAR(R) !Read the desired record's bits.
END SUBROUTINE GETSREC !Done.
INTEGER FUNCTION PRIME(N) !P(1) = 2, P(2) = 3, etc.
C Calculate P(n) ~ n.ln(n)
C ~ n{ln(n) + ln(ln(n)) - 1 + (ln(ln(n)) - 2)/ln(n) - [ln(ln(n))**2 - 6*log(log(n)) + 11]/[2*(ln(n))**2] + ....}
C J.B.Rosser's 1938 Theorem: n[ln(n) + ln(ln(n)) - 1] < P(n) < n[ln(n) + ln(ln(n))]
C or, with E = ln(n) + ln(ln(n)), n[E - 1] < P(n) < n[E]
C Experimentation shows that the undershoot of the first two terms involves many records worth of bits.
C Including additional terms does much better, but can overshoot.
INTEGER N !The desired one.
INTEGER R,NP !Counts.
INTEGER B,C !Bit and character indices.
DOUBLE PRECISION EST,LN,LLN !Hope, if not actuality.
IF (N.LE.0) STOP "Primes are counted positively!" !Something must be wrong!
IF (N.LE.1) THEN !The start of the bit array being preempted.
PRIME = 2 !So, no array access.
ELSE !Otherwise, the fun begins.
LN = LOG(DFLOAT(N)) !Here we go.
LLN = LOG(LN) !A popular term.
EST = N*(LN !Estimate the value of the N'th prime.
1 + LLN - 1 !Second term
2 + (LLN - 2)/LN !Third term.
3 - (LLN**2 - 6*LLN + 11)/(2*LN**2)) !Fourth term.
R = (EST - SORG)/(2*SBITS) + 1 !Thereby selecting a record to scan.
IF (R.LE.0) R = 1 !And not making a mess with N < 6 or so.
9 CALL GETSREC(R) !Go for the record.
IF (R.LE.1) THEN !The first record starts with the record count.
NP = 1 !And I know how many primes precede its start point
ELSE !While for all subsequent records,
NP = I4UNPACK(C4) !This counts the number of primes that precede record R's start number.
END IF !So now I'm ready to count onwards.
IF (N.LE.NP) THEN !Maybe not.
R = R - 1 !The estimate took me too far ahead.
GO TO 9 !Try again.
END IF !Could escalate to a binary search or even an interpolating search.
Commence scanning the bits.
C = 0 !Start with the first character of SREC..
B = -1 !Syncopation. The formula is known to always under-estimate.
10 IF (NP.LT.N) THEN !Are we there yet?
11 B = B + 1 !No. Advance to the next bit.
IF (B.GE.8) THEN !Overflowed a character yet?
B = 0 !Yes. Start afresh at the first bit.
C = C + 1 !And advance one character.
IF (C.GE.SCHARS) THEN !Overflowed the record yet?
C = 0 !Yes. Start afresh at its first character.
R = R + 1 !And advance to the next record.
CALL GETSREC(R) !Possibly, create it.
END IF !So much for records.
END IF !We're now ready to test bit B of character C of record R.
IF (IAND(ICHAR(SCHAR(C)),ICHAR(BITON(B))).EQ.0) GO TO 11 !Not a prime. Search on.
NP = NP + 1 !Count another prime.
GO TO 10 !Pehaps this will be the one.
END IF !So much for the search.
PRIME = SORG + (R - 1)*(2*SBITS) + (C*8 + B)*2 !The corresponding number.
IF (PRIME.LE.0) WRITE (MSG,666) N,PRIME !Or, possibly not.
666 FORMAT ("Integer overflow! Prime(",I0,") gives ",I0,"!") !Let us hope the caller notices.
END IF !So, all going well,
END FUNCTION PRIME !It is found.
RECURSIVE INTEGER FUNCTION NEXTPRIME(N) !Keep right on to the end of the road.
Can invoke GETSREC, which can invoke PSURGE, which ... invokes NEXTPRIME. Oh dear.
INTEGER N !Not necessarily itself a prime number.
INTEGER NN !A value to work with.
INTEGER R !A record number into the stash.
INTEGER I,IST !Number offsets.
INTEGER C,B !Character and bit index.
IF (N.LE.1) THEN !Suspicion prevails.
NN = 2 !This is not represented in my bit array.
ELSE !Otherwise, the fun begins.
NN = N + 1 !Advance, with a copy I can mess with.
IF (MOD(NN,2).EQ.0) NN = NN + 1 !Thus, NN is now odd.
IF (NN.LE.0) GO TO 666 !But perhaps not proper, due to overflow.
R = (NN - SORG)/(2*SBITS) !SORG is odd, so (NN - SORG) is even.
CALL GETSREC(R + 1) !The first record is numbered one, not zero.
IST = SORG + R*(2*SBITS) !The number for its first bit: even numbers are omitted..
I = (NN - IST)/2 !Offset into the record. NN - IST is even.
C = I/8 !Which character in SCHAR(0:SCHARS - 1)?
B = MOD(I,8) !Which bit in SCHAR(C)?
10 IF (IAND(ICHAR(SCHAR(C)),ICHAR(BITON(B))).EQ.0) THEN !On for a prime.
NN = NN + 2 !Alas, it is off, so NN is not a prime. Perhaps this will be.
B = B + 1 !Advance one bit. Each bit steps two.
IF (B.GE.8) THEN !Past the end of the character?
B = 0 !Yes. Back to bit zero.
C = C + 1 !And advance one chracter.
IF (C.GE.SCHARS) THEN !Past the end of the record?
IF (NN.LE.0) GO TO 666!Yes. If NN has overflowed, the end of the rope is reached.
C = 0 !Back to the start of a record.
R = R + 1 !Advance one record.
CALL GETSREC(R + 1) !And read it. (Count is from 1, not 0).
END IF !So much for overflowing a record.
END IF !So much for overflowing a character.
GO TO 10 !Try again.
END IF !So much for the bit array.
END IF !If there had been a scan.
NEXTPRIME = NN !The number for which the scan stopped.
IF (NN.GT.0) RETURN !All is well.
666 WRITE (MSG,667) N,NN !Or, maybe not. Careful: this won't appear if NEXTPRIME is invoked in a WRITE list.
667 FORMAT ("Integer overflow! NextPrime(",I0,") gives ",I0,"!") !The recipient could do a two's complement.
NEXTPRIME = NN !Prefer to return the bad value rather than fail to return anything.
END FUNCTION NEXTPRIME !No divisions, no sieving. Here, anyway
INTEGER FUNCTION PREVIOUSPRIME(N) !If N is good, this can't overflow.
INTEGER N !The number, not necessarily a prime.
INTEGER NN !A value to mess with.
INTEGER R !A record number.
INTEGER I !Offset.
INTEGER C,B !Character and bit fingers.
IF (N.LE.3) THEN !Suppress annoyances.
NN = 2 !This is now called the first prime, not one.
ELSE !Otherwise, some work is to be done.
NN = N - 1 !Step back one to ensure previousness.
IF (MOD(NN,2).EQ.0) NN = NN - 1 !And here, oddness is a minimal requirement.
R = (NN - SORG)/(2*SBITS) !Finger the record containing the bit for NN.
CALL GETSREC(R + 1) !Record counting starts with one.
I = (NN - (SORG + R*(2*SBITS)))/2 !Offset into that record.
C = I/8 !Finger the character in SCHAR.
B = MOD(I,8) !And the bit within the character.
10 IF (IAND(ICHAR(SCHAR(C)),ICHAR(BITON(B))).EQ.0) THEN !On for a prime.
NN = NN - 2 !Alas, it is off, so NN is not a prime. Perhaps this will be.
B = B - 1 !Retreat one bit. Each bit steps two.
IF (B.LT.0) THEN !Past the start of the character?
B = 7 !Yes. Back to the last bit.
C = C - 1 !And retreat one chracter.
IF (C.LT.0) THEN !Past the start of the record?
C = SCHARS - 1 !Yes. Back to the end of a record.
R = R - 1 !Retreat one record.
CALL GETSREC(R + 1) !And read it. (Count is from 1, not 0).
END IF !So much for overflowing a record.
END IF !So much for overflowing a character.
GO TO 10 !Try again.
END IF !So much for the bit array.
END IF !Possibly, it was not needed.
PREVIOUSPRIME = NN !There.
END FUNCTION PREVIOUSPRIME !Doesn't overflow, either.
LOGICAL FUNCTION ISPRIME(N) !Could fool around explicity testing 2 and 3 and say 5,
INTEGER N !But that means also checking that N > 2, N > 3, and N > 5.
c ISPRIME = N .EQ. NEXTPRIME(N - 1) !This is so much easier, but involves scanning to reach the next prime.
INTEGER R,IST,I,C,B !Assistants for indexing the bit array.
IF (N.LE.1) THEN !First, preclude sillyness.
ISPRIME = .FALSE. !Not a prime.
ELSE IF (N.EQ.2) THEN !This is the only even number
ISPRIME = .TRUE. !That is a prime.
ELSE IF (MOD(N,2).EQ.0) THEN !Other even numbers
ISPRIME = .FALSE. !Are not prime numbers.
ELSE !Righto, now N is an odd number and there is a bit array for them.
R = (N - SORG)/(2*SBITS) !SORG is odd, so (N - SORG) is even.
CALL GETSREC(R + 1) !The first record is numbered one, not zero.
IST = SORG + R*(2*SBITS) !The number for its first bit: even numbers are omitted.
I = (N - IST)/2 !Offset into the record. N - IST is even.
C = I/8 !Which character in SCHAR(0:SCHARS - 1)?
B = MOD(I,8) !Which bit in SCHAR(C), indexing from zero?
ISPRIME = IAND(ICHAR(SCHAR(C)),ICHAR(BITON(B))).GT.0 !The bit is on for a prime.
END IF !All that fuss to find a single bit.
END FUNCTION ISPRIME !But, no divisions up to SQRT(N) or the like.
END MODULE PRIMEBAG !Functions updating a disc file as a side effect...
PROGRAM POKE
USE PRIMEBAG
INTEGER I,P,N,N1,N2 !Assorted assistants.
INTEGER ORDER !A collection of special values.
PARAMETER (ORDER = 6) !For one, two, and four byte integers.
INTEGER EDGE(ORDER) !Considered as two's complement and unsigned.
PARAMETER (EDGE = (/31,54,3512,6542,105097565,203280221/)) !These primes are of interest.
MSG = 6 !Standard output.
IF (.NOT.GRASPPRIMEBAG(66)) STOP "Gan't grab my file!" !Attempt in hope.
Case 1.
C FORALL(I = 1:20) LIST(I) = PRIME(I) is rejected because function Prime(i) is rather impure.
10 WRITE (MSG,11)
11 FORMAT (19X,"First twenty primes: ", $)
DO I = 1,20
P = PRIME(I)
WRITE (MSG,12) P
12 FORMAT (I0,",",$)
END DO
Case 2.
20 WRITE (MSG,21)
21 FORMAT (/,12X,"Primes between 100 and 150: ",$)
P = 100
22 P = NEXTPRIME(P) !While (P:=NextPrime(P)) <= 150 do Print P;
IF (P.LE.150) THEN !But alas, no assignment within an expression.
WRITE (MSG,23) P
23 FORMAT (I0,",",$)
GO TO 22
END IF
Case 3.
30 N1 = 7700 !Might as well parameterise this.
N2 = 8000 !Rather than litter the source with explicit integers.
N = 0
P = N1
31 P = NEXTPRIME(P)
IF (P.LE.N2) THEN
N = N + 1
GO TO 31
END IF
WRITE (MSG,32) N1,N2,N
32 FORMAT (/"Number of primes between ",I0," and ",I0,": ",I0)
Case 4.
40 WRITE (MSG,41)
41 FORMAT (/,"Tenfold steps...")
N = 1
DO I = 1,9 !This goes about as far as it can go.
P = PRIME(N)
WRITE (MSG,42) N,P
42 FORMAT ("Prime(",I0,") = ",I0)
N = N*10
END DO
Cast forth some interesting values.
100 WRITE (MSG,101)
101 FORMAT (/,"Primes close to number sizes")
DO N = 1,ORDER !Step through the list.
N1 = EDGE(N) - 1 !Syncopation for the special value.
DO I = 1,2 !I want the prime on either side.
N1 = N1 + 1 !So, there are two successive primes to finger.
WRITE (MSG,102) N1 !Identify the index.
102 FORMAT ("Prime(",I0,") = ",$) !Piecemeal writing to the output,
P = PRIME(N1) !As this may fling forth a complaint.
WRITE (MSG,103) P !Show the value returned.
103 FORMAT (I0,", ",$) !Which may be unexpected.
END DO !On to the second.
WRITE (MSG,*) !End the line after the second result.
END DO !On to the next in the list.
END !Whee!

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@ -0,0 +1,5 @@
P = NEXTPRIME(100)
DO WHILE (P.LE.150)
...stuff...
P = NEXTPRIME(P)
END DO

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@ -0,0 +1 @@
P:=100; WHILE (P:=NextPrime(P)) <= 150 DO stuff;

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* incremental Sieve of Eratosthenes based on the paper,
* "Two Compact Incremental Prime Sieves"
SUBROUTINE nextprime(no init, p)
IMPLICIT NONE
INTEGER*2, SAVE, ALLOCATABLE :: sieve(:,:)
INTEGER, SAVE :: r, s, pos, n, f1, f2, sz
INTEGER i, j, d, next, p, f3
LOGICAL no init, is prime
IF (no init) GO TO 10
IF (ALLOCATED(sieve)) DEALLOCATE(sieve)
* Each row in the sieve is a stack of 8 short integers. The
* stacks will never overflow since the product 2*3*5 ... *29
* (10 primes) exceeds a 32 bit integer. 2 is not stored in the sieve.
ALLOCATE(sieve(8,3))
sieve = reshape([(0_2, i = 1, 24)], shape(sieve))
r = 3
s = 9
pos = 1
sz = 1 ! sieve starts with size = 1
f1 = 2 ! Fibonacci sequence for allocating new capacities
f2 = 3 ! array starts with capacity 3
n = 1
p = 2 ! return our first prime
RETURN
10 n = n + 2
is prime = .true.
IF (sieve(1, pos) .eq. 0) GO TO 20 ! n is non-smooth w.r.t sieve
is prime = .false. ! element at sieve(pos) divides n
DO 17, i = 1, 8
Clear the stack of divisors by moving them to the next multiple
d = sieve(i, pos)
IF (d .eq. 0) GO TO 20 ! stack is empty
IF (d .lt. 0) d = d + 65536 ! correct storage overflow
sieve(i, pos) = 0
next = mod(pos + d - 1, sz) + 1
* Push divisor d on to the stack of the next multiple
j = 1
12 IF (sieve(j, next) .eq. 0) GO TO 15
j = j + 1
GO TO 12
15 sieve(j, next) = d
17 CONTINUE
Check if n is square; if so, then add sieving prime and advance
20 IF (n .lt. s) GO TO 30
IF (.not. is prime) GO TO 25
is prime = .false. ! r = √s divides n
next = mod(pos + r - 1, sz) + 1 ! however, r is prime, insert it.
j = 1
22 IF (sieve(j, next) .eq. 0) GO TO 23
j = j + 1
GO TO 22
23 sieve(j, next) = r
25 r = r + 2
s = r**2
Continue to the next array slot; grow the array by two when
* we get to the end to maintain the invariant size(sieve) > n
* IF the size exceeds the array capacity, resize the arary.
30 pos = pos + 1
IF (pos .le. sz) GO TO 40
sz = sz + 2
pos = 1
IF (sz .le. f2) GO TO 40 ! so far, no need to grow
f3 = f1 + f2
f1 = f2
f2 = f3
sieve = reshape(sieve, [8, f2],
& pad = [(0_2, i = 1, 8*(f2 - f1))])
* Either return n back to the caller or circle back if n
* turned out to be composite.
40 IF (.not. is prime) GO TO 10
p = n
END SUBROUTINE

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@ -0,0 +1,44 @@
INCLUDE 'sieve.f'
PROGRAM RC Extensible Sieve
IMPLICIT INTEGER (A-Z)
WRITE (*, '(A)', advance='no')
& 'The first 20 primes:'
CALL nextprime(.false., p)
DO 10, i = 1, 20
WRITE (*, '(I3)', advance = 'no') p
10 CALL nextprime(.true., p)
WRITE (*, *)
WRITE (*, '(A)', advance = 'no')
& 'The primes between 100 and 150:'
20 CALL nextprime(.true., p)
IF (p .gt. 149) GO TO 30
IF (p .gt. 99)
& WRITE (*, '(I4)', advance = 'no') p
GO TO 20
30 WRITE (*, *)
count = 0
40 CALL nextprime(.true., p)
IF (p .gt. 7999) GO TO 50
IF (p .gt. 7700) count = count + 1
GO TO 40
50 WRITE (*, 100) count
100 FORMAT ('There are ', I0, ' primes between 7700 and 8000.')
CALL nextprime(.false., p) ! re-initialize
target = 1 ! target count
n = 0 ! number of primes generated
60 n = n + 1
IF (n .lt. target) GO TO 70
WRITE (*, '(ES7.1,1X,I12)'), real(n), p
IF (target .eq. 100 000 000) GO TO 80
target = target * 10
70 CALL nextprime(.true., p)
GO TO 60
80 END

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' FB 1.05.0
Enum SieveLimitType
number
between
countBetween
End Enum
Sub printPrimes(low As Integer, high As Integer, slt As SieveLimitType)
If high < low OrElse low < 1 Then Return ' too small
If slt <> number AndAlso slt <> between AndAlso slt <> countBetween Then Return
If slt <> number AndAlso (low < 2 OrElse high < 2) Then Return
If slt <> number AndAlso high > 1000000000 Then Return ' too big
If slt = number AndAlso high > 50000000 Then Return ' too big
Dim As Integer n
If slt = number Then
n = 20 * high '' big enough to accomodate 50 million primes to which this procedure is limited
Else
n = high
End If
Dim a(2 To n) As Boolean '' only uses 1 byte per element
For i As Integer = 2 To n : a(i) = True : Next '' set all elements to True to start with
Dim As Integer p = 2, q
' mark non-prime numbers by setting the corresponding array element to False
Do
For j As Integer = p * p To n Step p
a(j) = False
Next j
' look for next True element in array after 'p'
q = 0
For j As Integer = p + 1 To Sqr(n)
If a(j) Then
q = j
Exit For
End If
Next j
If q = 0 Then Exit Do
p = q
Loop
Select Case As Const slt
Case number
Dim count As Integer = 0
For i As Integer = 2 To n
If a(i) Then
count += 1
If count >= low AndAlso count <= high Then
Print i; " ";
End If
If count = high Then Exit Select
End If
Next
Case between
For i As Integer = low To high
If a(i) Then
Print i; " ";
End if
Next
Case countBetween
Dim count As Integer = 0
For i As Integer = low To high
If a(i) Then count += 1
Next
Print count;
End Select
Print
End Sub
Print "The first 20 primes are :"
Print
printPrimes(1, 20, number)
Print
Print "The primes between 100 and 150 are :"
Print
printPrimes(100, 150, between)
Print
Print "The number of primes between 7700 and 8000 is :";
printPrimes(7700, 8000, countBetween)
Print
Print "The 10000th prime is :";
Dim t As Double = timer
printPrimes(10000, 10000, number)
Print "Computed in "; CInt((timer - t) * 1000 + 0.5); " ms"
Print
Print "The 1000000th prime is :";
t = timer
printPrimes(1000000, 1000000, number)
Print "Computed in ";CInt((timer - t) * 1000 + 0.5); " ms"
Print
Print "The 50000000th prime is :";
t = timer
printPrimes(50000000, 50000000, number)
Print "Computed in ";CInt((timer - t) * 1000 + 0.5); " ms"
Print
Print "Press any key to quit"
Sleep

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@ -0,0 +1,4 @@
println["The first 20 primes are: " + first[primes[], 20]]
println["The primes between 100 and 150 are: " + primes[100,150]]
println["The number of primes between 7700 and 8000 are: " + length[primes[7700,8000]]]
println["The 10,000th prime is: " + nth[primes[], 10000-1]] // nth is zero-based

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package main
import (
"container/heap"
"fmt"
)
func main() {
p := newP()
fmt.Print("First twenty: ")
for i := 0; i < 20; i++ {
fmt.Print(p(), " ")
}
fmt.Print("\nBetween 100 and 150: ")
n := p()
for n <= 100 {
n = p()
}
for ; n < 150; n = p() {
fmt.Print(n, " ")
}
for n <= 7700 {
n = p()
}
c := 0
for ; n < 8000; n = p() {
c++
}
fmt.Println("\nNumber beween 7,700 and 8,000:", c)
p = newP()
for i := 1; i < 10000; i++ {
p()
}
fmt.Println("10,000th prime:", p())
}
func newP() func() int {
n := 1
var pq pQueue
top := &pMult{2, 4, 0}
return func() int {
for {
n++
if n < top.pMult { // n is a new prime
heap.Push(&pq, &pMult{prime: n, pMult: n * n})
top = pq[0]
return n
}
// n was next on the queue, it's a composite
for top.pMult == n {
top.pMult += top.prime
heap.Fix(&pq, 0)
top = pq[0]
}
}
}
}
type pMult struct {
prime int
pMult int
index int
}
type pQueue []*pMult
func (q pQueue) Len() int { return len(q) }
func (q pQueue) Less(i, j int) bool { return q[i].pMult < q[j].pMult }
func (q pQueue) Swap(i, j int) {
q[i], q[j] = q[j], q[i]
q[i].index = i
q[j].index = j
}
func (p *pQueue) Push(x interface{}) {
q := *p
e := x.(*pMult)
e.index = len(q)
*p = append(q, e)
}
func (p *pQueue) Pop() interface{} {
q := *p
last := len(q) - 1
e := q[last]
*p = q[:last]
return e
}

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package main
import (
"fmt"
"github.com/jbarham/primegen.go"
)
func main() {
p := primegen.New()
fmt.Print("First twenty: ")
for i := 0; i < 20; i++ {
fmt.Print(p.Next(), " ")
}
fmt.Print("\nBetween 100 and 150: ")
p.SkipTo(100)
for n := p.Next(); n < 150; n = p.Next() {
fmt.Print(n, " ")
}
p.SkipTo(7700)
fmt.Println("\nNumber beween 7,700 and 8,000:", p.Count(8000))
p.Reset()
for i := 1; i < 1e4; i++ {
p.Next()
}
fmt.Println("10,000th prime:", p.Next())
}

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#!/usr/bin/env runghc
import Data.List
import Data.Numbers.Primes
import System.IO
firstNPrimes :: Integer -> [Integer]
firstNPrimes n = genericTake n primes
primesBetweenInclusive :: Integer -> Integer -> [Integer]
primesBetweenInclusive lo hi =
dropWhile (< lo) $ takeWhile (<= hi) primes
nthPrime :: Integer -> Integer
nthPrime n = genericIndex primes (n - 1) -- beware 0-based indexing
main = do
hSetBuffering stdout NoBuffering
putStr "First 20 primes: "
print $ firstNPrimes 20
putStr "Primes between 100 and 150: "
print $ primesBetweenInclusive 100 150
putStr "Number of primes between 7700 and 8000: "
print $ genericLength $ primesBetweenInclusive 7700 8000
putStr "The 10000th prime: "
print $ nthPrime 10000

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@ -0,0 +1,11 @@
λ> take 20 primesW
[2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71]
λ> takeWhile (< 150) . dropWhile (< 100) $ primesW
[101,103,107,109,113,127,131,137,139,149]
λ> length . takeWhile (< 8000) . dropWhile (< 7700) $ primesW
30
λ> (!! (10000-1)) primesW
104729

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@ -0,0 +1,68 @@
{-# LANGUAGE PostfixOperators #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleInstances #-}
import Data.Numbers.Primes
import Data.Array.Unboxed hiding ((!))
import qualified Data.Array.Unboxed as Array
import Data.CReal
import Data.CReal.Internal
import GHC.TypeLits
instance KnownNat n => Enum (CReal n) where
toEnum i = fromIntegral i
fromEnum _ = error "Cannot fromEnum CReal"
enumFrom = iterate (+ 1)
enumFromTo n e = takeWhile (<= e) $ iterate (+ 1)n
enumFromThen n m = iterate (+(m-n)) n
enumFromThenTo n m e = if m >= n then takeWhile (<= e) $ iterate (+(m-n)) n
else takeWhile (>= e) $ iterate (+(m-n)) n
-- partial_sum x y a b = (p,q) where
-- p/q = sum_{a<i<=b} x(i) / poduct_{a<j<=j} y(j)
-- The complexity of partial_sum x y 0 n is O(n log n)
partial_sum x y = pq where
pq a b = if a>=b then (0,1)
else if a==b-1 then (fromIntegral $ x b, fromIntegral $ y b )
else (p_ab,q_ab)
where
c=(a+b) `div` 2
(p_ac,q_ac) = pq a c
(p_cb,q_cb) = pq c b
p_ab = p_cb + q_cb*p_ac
q_ab = q_ac*q_cb
-- c is the real constant that is used in the formula for primes
-- c = sum_{1<i} p_i / (2i+1)!
-- where p_i is i-th prime.
-- This will work for any sequence of integers p, where |p_n| < 2n(2n+1) * 0.375
c = crMemoize f where
f n = 2^n * p `div` q where
n' = fromIntegral n
u = head [ceiling (x) | x<-[(n' * log 2/ (log n'-1)/2 ) ..] , 2*x*log (2*x) - 2*x > n'*log 2]
-- Invariant: (2u+1)! > 2^n
ar :: UArray Int Int
ar = listArray (1,u) $ primes
(p,q) = partial_sum (ar Array.!) (\n-> 2*n*(2*n+1) ) 0 u
-- Fractorial part of x
-- By definition it is in the interval [-0.5; 0.5]
-- But it gurantes to work corectly if fractional part of x is in (-0.375; 0.375)
fract x = x - fromIntegral (round (x :: CReal 3))
-- Factorial.
-- The complexity of (n!) is O(n log n) (which is better than O(n^2) for product [1..n] )
(!) :: (RealFrac a, Num b) => a -> b
(!) = fromIntegral . snd . partial_sum (const 0) id 0 . round
-- Analytic function for n-th prime.
-- NB. Strictly speaking this function is not analytic, because it uses factorial, fractional part and round functions
-- To make it truly analytic you need to replace
-- fract x = acos (cos (2*pi*x)) / (2*pi)
-- round x = x - fract x
-- and use the Gamma function instead of factorial.
-- Then you will get analytic function prime :: CReal 0 -> CReal 0
prime n = round( 2*n*(2*n+1) * fract ( c * ((2*n-1)!)))

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@ -0,0 +1,13 @@
λ> :set +s
λ> prime 10000
104729
(0.32 secs, 179,899,272 bytes)
λ> length $ dropWhile (< 7700) $ takeWhile (< 8000) $ map prime [1..]
30
(3.09 secs, 3,418,225,920 bytes)
λ> dropWhile (< 100) $ takeWhile (< 150) $ map prime [1..]
[101,103,107,109,113,127,131,137,139,149]
(0.02 secs, 20,239,464 bytes)
λ> map prime [1..20]
[2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71]
(0.01 secs, 10,485,208 bytes)

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@ -0,0 +1 @@
![2,3,5,7] | (nc := 11) | (nc +:= |wheel2345)

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@ -0,0 +1,38 @@
import Collections # to get the Heap class for use as a Priority Queue
record filter(composite, prime) # next composite involving this prime
procedure main()
every writes((primes()\20)||" " | "\n")
every p := primes() do if 100 < p < 150 then writes(p," ") else if p >= 150 then break write()
every (n := 0, p := primes()) do if 7700 < p < 8000 then n +:= 1 else if p >= 8000 then break write(n)
every (i := 1, p := primes()) do if (i+:=1) >= 10000 then break write(p)
end
procedure primes()
local wheel2357, nc
wheel2357 := [2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6, 2, 6, 4, 2,
6, 4, 6, 8, 4, 2, 4, 2, 4, 8, 6, 4, 6, 2, 4, 6,
2, 6, 6, 4, 2, 4, 6, 2, 6, 4, 2, 4, 2, 10, 2, 10]
suspend sieve(Heap(,getCompositeField), ![2,3,5.7] | (nc := 11) | (nc +:= |!wheel2357))
end
procedure sieve(pQueue, candidate)
local nc
if 0 = pQueue.size() then { # 2 is prime
pQueue.add(filter(candidate*candidate, candidate))
return candidate
}
while candidate > (nc := pQueue.get()).composite do {
nc.composite +:= nc.prime
pQueue.add(nc)
}
pQueue.add(filter(nc.composite+nc.prime, nc.prime))
if candidate < nc.composite then { # new prime found!
pQueue.add(filter(candidate*candidate, candidate))
return candidate
}
end
# Provide a function for comparing filters in the priority queue...
procedure getCompositeField(x); return x.composite; end

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@ -0,0 +1,8 @@
p:i.20
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71
(#~ >:&100)i.&.(p:inv) 150
101 103 107 109 113 127 131 137 139 149
#(#~ >:&7700)i.&.(p:inv) 8000
30
p:10000-1
104729

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@ -0,0 +1,2 @@
4 p: 104729
104743

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@ -0,0 +1,114 @@
import java.util.*;
public class PrimeGenerator {
private int limit_;
private int index_ = 0;
private int increment_;
private int count_ = 0;
private List<Integer> primes_ = new ArrayList<>();
private BitSet sieve_ = new BitSet();
private int sieveLimit_ = 0;
public PrimeGenerator(int initialLimit, int increment) {
limit_ = nextOddNumber(initialLimit);
increment_ = increment;
primes_.add(2);
findPrimes(3);
}
public int nextPrime() {
if (index_ == primes_.size()) {
if (Integer.MAX_VALUE - increment_ < limit_)
return 0;
int start = limit_ + 2;
limit_ = nextOddNumber(limit_ + increment_);
primes_.clear();
findPrimes(start);
}
++count_;
return primes_.get(index_++);
}
public int count() {
return count_;
}
private void findPrimes(int start) {
index_ = 0;
int newLimit = sqrt(limit_);
for (int p = 3; p * p <= newLimit; p += 2) {
if (sieve_.get(p/2 - 1))
continue;
int q = p * Math.max(p, nextOddNumber((sieveLimit_ + p - 1)/p));
for (; q <= newLimit; q += 2*p)
sieve_.set(q/2 - 1, true);
}
sieveLimit_ = newLimit;
int count = (limit_ - start)/2 + 1;
BitSet composite = new BitSet(count);
for (int p = 3; p <= newLimit; p += 2) {
if (sieve_.get(p/2 - 1))
continue;
int q = p * Math.max(p, nextOddNumber((start + p - 1)/p)) - start;
q /= 2;
for (; q >= 0 && q < count; q += p)
composite.set(q, true);
}
for (int p = 0; p < count; ++p) {
if (!composite.get(p))
primes_.add(p * 2 + start);
}
}
private static int sqrt(int n) {
return nextOddNumber((int)Math.sqrt(n));
}
private static int nextOddNumber(int n) {
return 1 + 2 * (n/2);
}
public static void main(String[] args) {
PrimeGenerator pgen = new PrimeGenerator(20, 200000);
System.out.println("First 20 primes:");
for (int i = 0; i < 20; ++i) {
if (i > 0)
System.out.print(", ");
System.out.print(pgen.nextPrime());
}
System.out.println();
System.out.println("Primes between 100 and 150:");
for (int i = 0; ; ) {
int prime = pgen.nextPrime();
if (prime > 150)
break;
if (prime >= 100) {
if (i++ != 0)
System.out.print(", ");
System.out.print(prime);
}
}
System.out.println();
int count = 0;
for (;;) {
int prime = pgen.nextPrime();
if (prime > 8000)
break;
if (prime >= 7700)
++count;
}
System.out.println("Number of primes between 7700 and 8000: " + count);
int n = 10000;
for (;;) {
int prime = pgen.nextPrime();
if (prime == 0) {
System.out.println("Can't generate any more primes.");
break;
}
if (pgen.count() == n) {
System.out.println(n + "th prime: " + prime);
n *= 10;
}
}
}
}

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@ -0,0 +1,41 @@
function primeGenerator(num, showPrimes) {
var i,
arr = [];
function isPrime(num) {
// try primes <= 16
if (num <= 16) return (
num == 2 || num == 3 || num == 5 || num == 7 || num == 11 || num == 13
);
// cull multiples of 2, 3, 5 or 7
if (num % 2 == 0 || num % 3 == 0 || num % 5 == 0 || num % 7 == 0)
return false;
// cull square numbers ending in 1, 3, 7 or 9
for (var i = 10; i * i <= num; i += 10) {
if (num % (i + 1) == 0) return false;
if (num % (i + 3) == 0) return false;
if (num % (i + 7) == 0) return false;
if (num % (i + 9) == 0) return false;
}
return true;
}
if (typeof num == "number") {
for (i = 0; arr.length < num; i++) if (isPrime(i)) arr.push(i);
// first x primes
if (showPrimes) return arr;
// xth prime
else return arr.pop();
}
if (Array.isArray(num)) {
for (i = num[0]; i <= num[1]; i++) if (isPrime(i)) arr.push(i);
// primes between x .. y
if (showPrimes) return arr;
// number of primes between x .. y
else return arr.length;
}
// throw a default error if nothing returned yet
// (surrogate for a quite long and detailed try-catch-block anywhere before)
throw("Invalid arguments for primeGenerator()");
}

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@ -0,0 +1,11 @@
// first 20 primes
console.log(primeGenerator(20, true));
// primes between 100 and 150
console.log(primeGenerator([100, 150], true));
// numbers of primes between 7700 and 8000
console.log(primeGenerator([7700, 8000], false));
// the 10,000th prime
console.log(primeGenerator(10000, false));

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@ -0,0 +1,7 @@
Array [ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 51, 59, 61, 67, 71 ]
Array [ 101, 103, 107, 109, 113, 127, 131, 137, 139, 149 ]
30
104729

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@ -0,0 +1,9 @@
# Recent versions of jq include the following definition:
# until/2 loops until cond is satisfied,
# and emits the value satisfying the condition:
def until(cond; next):
def _until:
if cond then . else (next|_until) end;
_until;
def count(cond): reduce .[] as $x (0; if $x|cond then .+1 else . end);

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@ -0,0 +1,33 @@
# Is the input integer a prime?
# "previous" must be the array of sorted primes greater than 1 up to (.|sqrt)
def is_prime(previous):
. as $in
| (previous|length) as $plength
| [false, 0] # state: [found, ix]
| until( .[0] or .[1] >= $plength;
[ ($in % previous[.[1]]) == 0, .[1] + 1] )
| .[0] | not ;
# extend_primes expects its input to be an array consisting of
# previously found primes, in order, and extends that array:
def extend_primes:
if . == null or length == 0 then [2]
else . as $previous
| if . == [2] then [2,3]
else . + [(2 + .[length-1]) | until( is_prime($previous) ; . + 2)]
end
end;
# If . is an integer > 0 then produce an array of . primes;
# otherwise emit an unbounded stream of primes:
def primes:
. as $n
| if type == "number" and $n > 0 then
null | until( length == $n; extend_primes )
else [2] | recurse(extend_primes) | .[length - 1]
end;
# Primes up to and possibly including n:
def primes_upto(n):
until( .[length-1] > n; extend_primes )
| if .[length-1] > n then .[0:length-1] else . end;

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@ -0,0 +1,9 @@
"First 20 primes:", (20 | primes), "",
"Primes between 100 and 150:",
(primes_upto(150) | map(select( 100 < .))), "",
"The 10,000th prime is \( 10000 | primes | .[length - 1] )", "",
(( primes_upto(8000) | count( . > 7700) | length) as $length
| "There are \($length) primes twixt 7700 and 8000.")

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@ -0,0 +1,10 @@
$ jq -r -c -n -f Extensible_prime_generator.jq
First 20 primes:
[2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71]
Primes between 100 and 150:
[101,103,107,109,113,127,131,137,139,149]
The 10,000th prime is 104729
There are 30 primes twixt 7700 and 8000.

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@ -0,0 +1,21 @@
using Primes
sum = 2
currentprime = 2
for i in 2:100000
currentprime = nextprime(currentprime + 1)
sum += currentprime
end
println("The sum of the first 100,000 primes is $sum")
curprime = 1
arr = zeros(Int, 20)
for i in 1:20
curprime = nextprime(curprime + 1)
arr[i] = curprime
end
println("The first 20 primes are ", arr)
println("the primes between 100 and 150 are ", primes(100,150))
println("The number of primes between 7,700 and 8,000 is ", length(primes(7700, 8000)))
println("The 10,000th prime is ", prime(10000))

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@ -0,0 +1,19 @@
using Primes: isprime
PrimesGen() = Iterators.filter(isprime, Iterators.countfrom(Int64(2)))
print("Sum of first 100,000 primes: ")
println(Iterators.sum(Iterators.take(PrimesGen(), 100000)))
print("First 20 primes: ( ")
foreach((p->print(p," ")), Iterators.take(PrimesGen(), 20))
println(")")
print("Primes between 100 and 150: ( ")
for p in Iterators.filter((p->p>=100), PrimesGen()) p > 150 && break; print(p, " ") end
println(")")
let cnt = 0
for p in PrimesGen()
p > 8000 && break; if p > 7700 cnt += 1 end
end; println("Number of primes between 7700 and 8000: ", cnt)
end
println("The 10,000th prime: ", Iterators.first(Iterators.drop(PrimesGen(), 9999)))
println()

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@ -0,0 +1,6 @@
using Printf: @printf
@time let sm = 0
for p in Iterators.filter(isprime, Iterators.countfrom(UInt64(2)))
p > 2000000 && break
sm += p
end; @printf("%d\n", sm) end

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@ -0,0 +1,16 @@
using Printf: @printf
print("Sum of first 100,000 primes: ")
println(Iterators.sum(Iterators.take(PrimesPaged(), 100000)))
print("First 20 primes: ( ")
foreach((p->@printf("%d ", p)), Iterators.take(PrimesPaged(), 20))
println(")")
print("Primes between 100 and 150: ( ")
for p in Iterators.filter((p->p>=100), PrimesPaged()) p > 150 && break; @printf("%d ", p)) end
println(")")
let cnt = 0
for p in PrimesPaged()
p > 8000 && break; if p > 7700 cnt += 1 end
end; println("Number of primes between 7700 and 8000: ", cnt)
end
@printf("The 10,000th prime: %d\n", Iterators.first(Iterators.drop(PrimesPaged(), 9999)))

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@ -0,0 +1,6 @@
using Printf: @printf
@time let sm = 0
for p in PrimesPaged()
p > 2000000 && break
sm += p
end; @printf("%d\n", sm) end

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@ -0,0 +1,30 @@
fun isPrime(n: Int) : Boolean {
if (n < 2) return false
if (n % 2 == 0) return n == 2
if (n % 3 == 0) return n == 3
var d : Int = 5
while (d * d <= n) {
if (n % d == 0) return false
d += 2
if (n % d == 0) return false
d += 4
}
return true
}
fun generatePrimes() = sequence {
yield(2)
var p = 3
while (p <= Int.MAX_VALUE) {
if (isPrime(p)) yield(p)
p += 2
}
}
fun main(args: Array<String>) {
val primes = generatePrimes().take(10000) // generate first 10,000 primes
println("First 20 primes : ${primes.take(20).toList()}")
println("Primes between 100 and 150 : ${primes.filter { it in 100..150 }.toList()}")
println("Number of primes between 7700 and 8000 = ${primes.filter { it in 7700..8000 }.count()}")
println("10,000th prime = ${primes.last()}")
}

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fun primesHM(): Sequence<Int> = sequence {
yield(2)
fun oddprms(): Sequence<Int> = sequence {
yield(3); yield(5) // need at least 2 for initialization
val hm = HashMap<Int,Int>()
hm.put(9, 6)
val bps = oddprms().iterator(); bps.next(); bps.next() // skip past 5
yieldAll(generateSequence(SieveState(7, 5, 25)) {
ss ->
var n = ss.n; var q = ss.q
n += 2
while ( n >= q || hm.containsKey(n)) {
if (n >= q) {
val inc = ss.bp shl 1
hm.put(n + inc, inc)
val bp = bps.next(); ss.bp = bp; q = bp * bp
}
else {
val inc = hm.remove(n)!!
var next = n + inc
while (hm.containsKey(next)) {
next += inc
}
hm.put(next, inc)
}
n += 2
}
ss.n = n; ss.q = q
ss
}.map { it.n })
}
yieldAll(oddprms())
}

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primesPaged().takeWhile { it <= 1_000_000_000 }.count()

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-- parent script "sieve"
property _sieve
----------------------------------------
-- @constructor
----------------------------------------
on new (me)
me._sieve = []
me._primeSieve(100) -- arbitrary initial size of sieve
return me
end
----------------------------------------
-- Returns sorted list of first n primes p with p >= a (default: a=1)
----------------------------------------
on getNPrimes (me, n, a)
if voidP(a) then a = 1
i = a
res = []
repeat while TRUE
if i>me._sieve.count then me._primeSieve(2*i)
if me._sieve[i] then res.add(i)
if res.count=n then return res
i = i +1
end repeat
end
----------------------------------------
-- Returns sorted list of primes p with a <= p <= b
----------------------------------------
on getPrimesInRange (me, a, b)
if me._sieve.count<b then me._primeSieve(b)
primes = []
repeat with i = a to b
if me._sieve[i] then primes.add(i)
end repeat
return primes
end
----------------------------------------
-- Returns nth prime
----------------------------------------
on getNthPrime (me, n)
if me._sieve.count<2*n then me._primeSieve(2*n)
i = 0
found = 0
repeat while TRUE
i = i +1
if i>me._sieve.count then me._primeSieve(2*i)
if me._sieve[i] then found=found+1
if found=n then return i
end repeat
end
----------------------------------------
-- Sieve of Eratosthenes
----------------------------------------
on _primeSieve (me, limit)
if me._sieve.count>=limit then
return
else if me._sieve.count>0 then
return me._complementSieve(limit)
end if
me._sieve = [0]
repeat with i = 2 to limit
me._sieve[i] = 1
end repeat
c = sqrt(limit)
repeat with i = 2 to c
if (me._sieve[i]=0) then next repeat
j = i*i
repeat while (j<=limit)
me._sieve[j] = 0
j = j + i
end repeat
end repeat
end
----------------------------------------
-- Expands existing sieve to new limit
----------------------------------------
on _complementSieve (me, n)
n1 = me._sieve.count
repeat with i = n1+1 to n
me._sieve[i] = 1
end repeat
c1 = sqrt(n1)
repeat with i = 2 to c1
if (me._sieve[i]=0) then next repeat
j = n1 - (n1 mod i)
repeat while (j<=n)
me._sieve[j] = 0
j = j + i
end repeat
end repeat
c = sqrt(n)
repeat with i = c1+1 to c
if (me._sieve[i]=0) then next repeat
j = i*i
repeat while (j<=n)
me._sieve[j] = 0
j = j + i
end repeat
end repeat
end

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sieve = script("sieve").new()
put "First twenty primes: " & sieve.getNPrimes(20)
put "Primes between 100 and 150: "& sieve.getPrimesInRange(100, 150)
put "Number of primes between 7,700 and 8,000: " & sieve.getPrimesInRange(7700, 8000).count
put "The 10,000th prime: " & sieve.getNthPrime(10000)

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local primegen = {
count_limit = 2,
value_limit = 3,
primelist = { 2, 3 },
nextgenvalue = 5,
nextgendelta = 2,
tbd = function(n)
if n < 2 then return false end
if n % 2 == 0 then return n==2 end
if n % 3 == 0 then return n==3 end
local limit = math.sqrt(n)
for f = 5, limit, 6 do
if n % f == 0 or n % (f+2) == 0 then return false end
end
return true
end,
needmore = function(self)
return (self.count_limit ~= nil and #self.primelist < self.count_limit)
or (self.value_limit ~= nil and self.nextgenvalue < self.value_limit)
end,
generate = function(self, count_limit, value_limit)
self.count_limit = count_limit
self.value_limit = value_limit
while self:needmore() do
if (self.tbd(self.nextgenvalue)) then
self.primelist[#self.primelist+1] = self.nextgenvalue
end
self.nextgenvalue = self.nextgenvalue + self.nextgendelta
self.nextgendelta = 6 - self.nextgendelta
end
end,
filter = function(self, f)
local list = {}
for k,v in ipairs(self.primelist) do
if (f(v)) then list[#list+1] = v end
end
return list
end,
}
primegen:generate(20, nil)
print("First 20 primes: " .. table.concat(primegen.primelist, ", "))
primegen:generate(nil, 150)
print("Primes between 100 and 150: " .. table.concat(primegen:filter(function(v) return v>=100 and v<=150 end), ", "))
primegen:generate(nil, 8000)
print("Number of primes between 7700 and 8000: " .. #primegen:filter(function(v) return v>=7700 and v<=8000 end))
primegen:generate(10000, nil)
print("The 10,000th prime: " .. primegen.primelist[#primegen.primelist])
primegen:generate(100000, nil)
print("The 100,000th prime: " .. primegen.primelist[#primegen.primelist])

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Module CheckPrimes {
\\ Inventories are lists, Known and Known1 are pointers to Inventories
Inventory Known=1:=2@,2:=3@,3:=5@
Inventory Known1=2@, 3@, 5@
\\ In a lambda all closures are copies
\\ but Known and Know1 are copies of pointers
\\ so are closures like by reference
PrimeNth=lambda Known, Known1 (n as long) -> {
if n<1 then Error "Only >=1"
if exist(known, n) then =eval(known) : exit
if n>5 then {
i=len(known1)
x=eval(known1, i-1)+2
} else x=5 : i=2
{
if i=n then =known(n) : exit
ok=false
if frac(x) then 1000
if frac(x/2) else 1000
if frac(x/3) else 1000
x1=sqrt(x) : d=5@
Repeat
if frac(x/d ) else exit
d += 2: if d>x1 then ok=true : exit
if frac(x/d) else exit
d += 4: if d<= x1 else ok=true: exit
Always
1000 If ok then i++:Append Known, i:=x : if not exist(Known1, x) then Append Known1, x
x+=2 : Loop }
}
\\ IsPrime has same closure, Known1
IsPrime=lambda Known1 (x as decimal) -> {
if exist(Known1, x) then =true : exit
if Eval(Known1, len(Known1)-1)>x then exit
if frac(x/2) else exit
if frac(x/3) else exit
x1=sqrt(x):d = 5@
{if frac(x/d ) else exit
d += 2: if d>x1 then =true : exit
if frac(x/d) else exit
d += 4: if d<= x1 else =true: exit
loop
}
}
\\ fill Known1, PrimeNth is a closure here
IsPrime2=lambda Known1, PrimeNth (x as decimal) -> {
if exist(Known1, x) then =true : exit
i=len(Known1)
if Eval(Known1, i-1)>x then exit
{
z=PrimeNth(i)
if z<x then loop else.if z=x then =true :exit
i++
}
}
Print "First twenty primes"
n=PrimeNth(20)
For i=1 to 20 : Print Known(i),: Next i
Print
Print "Primes between 100 and 150:"
c=0
For i=100 to 150
If IsPrime2(i) Then print i, : c++
Next i
Print
Print "Count:", c
Print "Primes between 7700 and 8000:"
c=0
For i=7700 to 8000
If IsPrime(i) Then print i, : c++
Next i
Print
Print "Count:", c
Print "200th Prime:"
Print PrimeNth(200)
Print "List from 190th to 199th Prime:"
For i=190 to 199 : Print Known(i), : Next i
Print
Print "Wait"
Refresh ' because refresh happen on next Print, which take time
' using set fast! we get no respond from GUI/M2000 Console
' also Esc, Break and Ctrl+C not work
' we have to use Refresh each 500 primes to have one Refresh
Set fast !
for i=500 to 10000 step 50: m=PrimeNth(i): Print "."; :Refresh:Next i
Print
Print "10000th Prime:", PrimeNth(10000)
' reset speed to fast (there are three levels: slow/fast/fast!)
set fast
Print
Rem 1 : Print Known
Rem 2: Print Known1
}
CheckPrimes

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PrimeNth=lambda Known, Known1 (n as long) -> {
if n<1 then Error "Only >=1"
if exist(known, n) then =eval(known) : exit
if n>5 then {
i=len(known1)
x=eval(known1, i-1)+2
} else x=5 : i=2
{
if i=n then =known(n) : exit
if frac(x) then 999
if frac(x/2) else 999
if frac(x/3) else 999
x1=sqrt(x) : d=5@
{if frac(x/d ) else 999
d += 2: if d>x1 then 1000
if frac(x/d) else 999
d += 4: if d<= x1 else 1000
loop
}
999 x++ : Restart
1000 i++:Append Known, i:=x : if not exist(Known1, x) then Append Known1, x
x++ : Loop }
}

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Prime[Range[20]]
{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71}
Select[Range[100,150], PrimeQ]
{101, 103, 107, 109, 113, 127, 131, 137, 139, 149}
PrimePi[8000] - PrimePi[7700]
30
Prime[10000]
104729

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import tables
type PrimeType = int
proc primesHashTable(): iterator(): PrimeType {.closure.} =
iterator output(): PrimeType {.closure.} =
# some initial values to avoid race and reduce initializations...
yield 2.PrimeType; yield 3.PrimeType; yield 5.PrimeType; yield 7.PrimeType
var h = initTable[PrimeType,PrimeType]()
var n = 9.PrimeType
let bps = primesHashTable()
var bp = bps() # advance past 2
bp = bps(); var q = bp * bp # to initialize with 3
while true:
if n >= q:
let inc = bp + bp
h[n + inc] = inc
bp = bps(); q = bp * bp
elif h.hasKey(n):
var inc: PrimeType
discard h.take(n, inc)
var nxt = n + inc
while h.hasKey(nxt): nxt += inc # ensure no duplicates
h[nxt] = inc
else: yield n
n += 2.PrimeType
output
var num = 0
stdout.write "The first 20 primes are: "
var iter = primesHashTable()
for p in iter():
if num >= 20: break else: stdout.write(p, " "); num += 1
echo ""
stdout.write "The primes between 100 and 150 are: "
iter = primesHashTable()
for p in iter():
if p >= 150: break
if p >= 100: stdout.write(p, " ")
echo ""
num = 0
iter = primesHashTable()
for p in iter():
if p > 8000: break
if p >= 7700: num += 1
echo "The number of primes between 7700 and 8000 is: ", num
num = 1
iter = primesHashTable()
for p in iter():
if num >= 10000:
echo "The 10,000th prime is: ", p
break
num += 1
var sum = 0
iter = primesHashTable()
for p in iter():
if p >= 2_000_000:
echo "The sum of the primes to two million is: ", sum
break
sum += p

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for p in primesPaged():

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@ -0,0 +1 @@
for p in iter():

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module IntMap = Map.Make(Int)
let rec steps =
4 :: 2 :: 4 :: 6 :: 2 :: 6 :: 4 :: 2 :: 4 :: 6 :: 6 :: 2 ::
6 :: 4 :: 2 :: 6 :: 4 :: 6 :: 8 :: 4 :: 2 :: 4 :: 2 :: 4 ::
8 :: 6 :: 4 :: 6 :: 2 :: 4 :: 6 :: 2 :: 6 :: 6 :: 4 :: 2 ::
4 :: 6 :: 2 :: 6 :: 4 :: 2 :: 4 :: 2 :: 10 :: 2 :: 10 :: 2 :: steps
let not_in_wheel =
let scan i =
let rec loop n w = n < 223 && (i = n mod 210
|| match w with [] -> assert false | d :: w' -> loop (n + d) w')
in not (loop 13 steps)
in Array.init 210 scan
let seq_primes =
let rec calc ms m p2 =
if not_in_wheel.(m mod 210) || IntMap.mem m ms
then calc ms (m + p2) p2
else IntMap.add m p2 ms
in
let rec next c p pp ps whl ms () =
match whl with
| [] -> assert false
| d :: w -> match IntMap.min_binding_opt ms with
| Some (m, p2) when c = m ->
next (c + d) p pp ps w (calc (IntMap.remove m ms) (m + p2) p2) ()
| _ when c < pp -> Seq.Cons (c, next (c + d) p pp ps w ms)
| _ -> match ps () with
| Seq.Cons (p', ps') -> let p2' = p + p in
next (c + d) p' (p' * p') ps' w (calc ms (pp + p2') p2') ()
| _ -> assert false
in
let rec ps () = next 13 11 121 ps steps IntMap.empty () in
Seq.cons 2 (Seq.cons 3 (Seq.cons 5 (Seq.cons 7 (Seq.cons 11 ps))))

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@ -0,0 +1,9 @@
let seq_show sq =
print_newline (Seq.iter (Printf.printf " %u") sq)
let () =
seq_primes |> Seq.take 20 |> seq_show;
seq_primes |> Seq.drop_while ((>) 100) |> Seq.take_while ((>) 150) |> seq_show;
seq_primes |> Seq.drop_while ((>) 7700) |> Seq.take_while ((>) 8000)
|> Seq.length |> Printf.printf " %u primes\n";
seq_primes |> Seq.drop 9999 |> Seq.take 1 |> seq_show

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@ -0,0 +1,10 @@
void
showprimes(GEN lower, GEN upper)
{
forprime_t T;
if (!forprime_init(&T, a,b)) return;
while(forprime_next(&T))
{
pari_printf("%Ps\n", T.pp);
}
}

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primes(20)
primes([100,150])
#primes([7700,8000]) /* or */
s=0; forprime(p=7700,8000,s++); s
prime(10000)

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unit primsieve;
{$IFDEF FPC}
{$MODE objFPC}{$Optimization ON,ALL}
{$IFEND}
{segmented sieve of Erathostenes using only odd numbers}
{using presieved sieve of small primes, to reduce the most time consuming}
interface
procedure InitPrime;
procedure NextSieve;
function SieveStart:Uint64;
function SieveSize :LongInt;
function Nextprime: Uint64;
function StartCount :Uint64;
function TotalCount :Uint64;
function PosOfPrime: Uint64;
implementation
uses
sysutils;
const
smlPrimes :array [0..10] of Byte = (2,3,5,7,11,13,17,19,23,29,31);
maxPreSievePrimeNum = 7;
maxPreSievePrime = 17;//smlPrimes[maxPreSievePrimeNum];
cSieveSize = 16384 * 4; //<= High(Word)+1 // Level I Data Cache
type
tSievePrim = record
svdeltaPrime:word;//diff between actual and new prime
svSivOfs:word; //Offset in sieve
svSivNum:LongWord;//1 shl (1+16+32) = 5.6e14
end;
tpSievePrim = ^tSievePrim;
var
//sieved with primes 3..maxPreSievePrime.here about 255255 Byte
{$ALIGN 32}
preSieve :array[0..3*5*7*11*13*17-1] of Byte;//must be > cSieveSize
{$ALIGN 32}
Sieve :array[0..cSieveSize-1] of Byte;
{$ALIGN 32}
//prime = FoundPrimesOffset + 2*FoundPrimes[0..FoundPrimesCnt]
FoundPrimes : array[0..cSieveSize] of word;
{$ALIGN 32}
sievePrimes : array[0..78498] of tSievePrim;// 1e6^2 ->1e12
// sievePrimes : array[0..664579] of tSievePrim;// maximum 1e14
FoundPrimesOffset : Uint64;
FoundPrimesCnt,
FoundPrimesIdx,
FoundPrimesTotal,
SieveNum,
SieveMaxIdx,
preSieveOffset,
LastInsertedSievePrime :NativeUInt;
procedure CopyPreSieveInSieve; forward;
procedure CollectPrimes; forward;
procedure sieveOneSieve; forward;
procedure Init0Sieve; forward;
procedure SieveOneBlock; forward;
//****************************************
procedure preSieveInit;
var
i,pr,j,umf : NativeInt;
Begin
fillchar(preSieve[0],SizeOf(preSieve),#1);
i := 1;
pr := 3;// starts with pr = 3
umf := 1;
repeat
IF preSieve[i] =1 then
Begin
pr := 2*i+1;
j := i;
repeat
preSieve[j] := 0;
inc(j,pr);
until j> High(preSieve);
umf := umf*pr;
end;
inc(i);
until (pr = maxPreSievePrime)OR(umf>High(preSieve)) ;
preSieveOffset := 0;
end;
function InsertSievePrimes(PrimPos:NativeInt):NativeInt;
var
delta :NativeInt;
i,pr,loLmt : NativeUInt;
begin
i := 0;
//ignore first primes already sieved with
if SieveNum = 0 then
i := maxPreSievePrimeNum;
pr :=0;
loLmt := Uint64(SieveNum)*(2*cSieveSize);
delta := loLmt-LastInsertedSievePrime;
with sievePrimes[PrimPos] do
Begin
pr := FoundPrimes[i]*2+1;
svdeltaPrime := pr+delta;
delta := pr;
end;
inc(PrimPos);
for i := i+1 to FoundPrimesCnt-1 do
Begin
IF PrimPos > High(sievePrimes) then
BREAK;
with sievePrimes[PrimPos] do
Begin
pr := FoundPrimes[i]*2+1;
svdeltaPrime := (pr-delta);
delta := pr;
end;
inc(PrimPos);
end;
LastInsertedSievePrime := loLmt+pr;
result := PrimPos;
end;
procedure CalcSievePrimOfs(lmt:NativeUint);
//lmt High(sievePrimes)
var
i,pr : NativeUInt;
sq : Uint64;
begin
pr := 0;
i := 0;
repeat
with sievePrimes[i] do
Begin
pr := pr+svdeltaPrime;
IF sqr(pr) < (cSieveSize*2) then
Begin
svSivNum := 0;
svSivOfs := (pr*pr-1) DIV 2;
end
else
Begin
SieveMaxIdx := i;
pr := pr-svdeltaPrime;
BREAK;
end;
end;
inc(i);
until i > lmt;
for i := i to lmt do
begin
with sievePrimes[i] do
Begin
pr := pr+svdeltaPrime;
sq := sqr(pr);
svSivNum := sq DIV (2*cSieveSize);
svSivOfs := ( (sq - Uint64(svSivNum)*(2*cSieveSize))-1)DIV 2;
end;
end;
end;
procedure sievePrimesInit;
var
i,j,pr,PrimPos:NativeInt;
Begin
LastInsertedSievePrime := 0;
preSieveOffset := 0;
SieveNum :=0;
CopyPreSieveInSieve;
//normal sieving of first block sieve
i := 1; // start with 3
repeat
while Sieve[i] = 0 do
inc(i);
pr := 2*i+1;
inc(i);
j := ((pr*pr)-1) DIV 2;
if j > High(Sieve) then
BREAK;
repeat
Sieve[j] := 0;
inc(j,pr);
until j > High(Sieve);
until false;
CollectPrimes;
PrimPos := InsertSievePrimes(0);
//correct for SieveNum = 0
CalcSievePrimOfs(PrimPos);
Init0Sieve;
sieveOneBlock;
//now start collect with SieveNum = 1
IF PrimPos < High(sievePrimes) then
repeat
sieveOneBlock;
CollectPrimes;
dec(SieveNum);
PrimPos := InsertSievePrimes(PrimPos);
inc(SieveNum);
until PrimPos > High(sievePrimes);
Init0Sieve;
end;
procedure Init0Sieve;
begin
FoundPrimesTotal :=0;
preSieveOffset := 0;
SieveNum :=0;
CalcSievePrimOfs(High(sievePrimes));
end;
procedure CopyPreSieveInSieve;
var
lmt : NativeInt;
Begin
lmt := preSieveOffset+cSieveSize;
lmt := lmt-(High(preSieve)+1);
IF lmt<= 0 then
begin
Move(preSieve[preSieveOffset],Sieve[0],cSieveSize);
if lmt <> 0 then
inc(preSieveOffset,cSieveSize)
else
preSieveOffset := 0;
end
else
begin
Move(preSieve[preSieveOffset],Sieve[0],cSieveSize-lmt);
Move(preSieve[0],Sieve[cSieveSize-lmt],lmt);
preSieveOffset := lmt
end;
end;
procedure sieveOneSieve;
var
sp:tpSievePrim;
pSieve :pByte;
i,j,pr,sn,dSievNum :NativeUint;
Begin
pr := 0;
sn := sieveNum;
sp := @sievePrimes[0];
pSieve := @Sieve[0];
For i := SieveMaxIdx downto 0 do
with sp^ do
begin
pr := pr+svdeltaPrime;
IF svSivNum = sn then
Begin
j := svSivOfs;
repeat
pSieve[j] := 0;
inc(j,pr);
until j > High(Sieve);
dSievNum := j DIV cSieveSize;
svSivOfs := j-dSievNum*cSieveSize;
svSivNum := sn+dSievNum;
// svSivNum := svSivNum+dSievNum;
end;
inc(sp);
end;
i := SieveMaxIdx+1;
repeat
if i > High(SievePrimes) then
BREAK;
with sp^ do
begin
if svSivNum > sn then
Begin
SieveMaxIdx := I-1;
Break;
end;
pr := pr+svdeltaPrime;
j := svSivOfs;
repeat
Sieve[j] := 0;
inc(j,pr);
until j > High(Sieve);
dSievNum := j DIV cSieveSize;
svSivOfs := j-dSievNum*cSieveSize;
svSivNum := sn+dSievNum;
end;
inc(i);
inc(sp);
until false;
end;
procedure CollectPrimes;
//extract primes to FoundPrimes
var
pSieve : pbyte;
pFound : pWord;
i,idx : NativeUint;
Begin
FoundPrimesOffset := SieveNum*(2*cSieveSize);
FoundPrimesIdx := 0;
pFound :=@FoundPrimes[0];
i := 0;
idx := 0;
IF SieveNum = 0 then
//include small primes used to pre-sieve
Begin
repeat
pFound[idx]:= (smlPrimes[idx]-1) DIV 2;
inc(idx);
until smlPrimes[idx]>maxPreSievePrime;
i := (smlPrimes[idx] -1) DIV 2;
end;
//grabbing the primes without if then -> reduces time extremly
//primes are born to let branch-prediction fail.
pSieve:= @Sieve[Low(Sieve)];
repeat
//store every value until a prime aka 1 is found
pFound[idx]:= i;
inc(idx,pSieve[i]);
inc(i);
until i>High(Sieve);
FoundPrimesCnt:= idx;
inc(FoundPrimesTotal,Idx);
end;
procedure SieveOneBlock;inline;
begin
CopyPreSieveInSieve;
sieveOneSieve;
CollectPrimes;
inc(SieveNum);
end;
procedure NextSieve;inline;
Begin
SieveOneBlock;
end;
function Nextprime:Uint64;
Begin
result := FoundPrimes[FoundPrimesIdx]*2+1+FoundPrimesOffset;
if (FoundPrimesIdx=0) AND (sievenum = 1) then
inc(result);
inc(FoundPrimesIdx);
If FoundPrimesIdx>= FoundPrimesCnt then
SieveOneBlock;
end;
function PosOfPrime: Uint64;inline;
Begin
result := FoundPrimesTotal-FoundPrimesCnt+FoundPrimesIdx;
end;
function StartCount : Uint64 ;inline;
begin
result := FoundPrimesTotal-FoundPrimesCnt;
end;
function TotalCount :Uint64;inline;
begin
result := FoundPrimesTotal;
end;
function SieveSize :LongInt;inline;
Begin
result := 2*cSieveSize;
end;
function SieveStart:Uint64;inline;
Begin
result := (SieveNum-1)*2*cSieveSize;
end;
procedure InitPrime;inline;
Begin
Init0Sieve;
SieveOneBlock;
end;
begin
preSieveInit;
sievePrimesInit;
InitPrime;
end.

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@ -0,0 +1,41 @@
program test;
{$IFDEF FPC}
{$MODE objFPC}{$Optimization ON,ALL}
{$IFEND}
uses
primsieve;
var
cnt,p,lmt : Uint64;
Begin
lmt := 1000*1000*1000;
p := 0;
while TotalCount < lmt do
Begin
NextSieve;
inc(p);
If p AND (4096-1) = 0 then
write(p:8,TotalCount:15,#13);
end;
cnt := StartCount;
repeat
p := NextPrime;
inc(cnt);
until cnt >= lmt;
writeln(cnt:14,p:14);
end.
{
10^n primecount
# 1 4
# 2 25
# 3 168
# 4 1229
# 5 9592
# 6 78498
# 7 664579
# 8 5761455
# 9 50847534
# 10 455052511
# 11 4118054813
# 12 37607912018
}

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@ -0,0 +1,655 @@
program emirp;
{$IFDEF FPC}
{$MODE DELPHI}
{$OPTIMIZATION ON,REGVAR,PEEPHOLE,CSE,ASMCSE}
{$CODEALIGN proc=8}
// {$R+,V+,O+}
{$ELSE}
{$APPLICATION CONSOLE}
{$ENDIF}
uses
sysutils;
type
tSievenum = NativeUint;
const
cBitSize = SizeOf(tSievenum)*8;
cAndMask = cBitSize-1;
InitPrim :array [0..9] of byte = (2,3,5,7,11,13,17,19,23,29);
(*
{MAXANZAHL = 2*3*5*7*11*13*17*19;*PRIM}
MAXANZAHL :array [0..8] of Longint =(2,6,30,210,2310,30030,
510510,9699690,223092870);
{WIFEMAXLAENGE = 1*2*4*6*10*12*16*18; *(PRIM-1)}
WIFEMAXLAENGE :array [0..8] of longint =(1,2,8,48,480,5760,
92160,1658880,36495360);
*)
//Don't sieve with primes that are multiples of 2..InitPrim[BIS]
BIS = 5;
MaxMulFac = 22; {array [0..9] of byte= (2,4,6,10,14,22,26,34,40,50);}
cMaxZahl = 30030;
cRepFldLen = 5760;
MaxUpperLimit = 100*1000*1000*1000-1;
MAXIMUM = ((MaxUpperLimit-1) DIV cMaxZahl+1)*cMaxZahl;
MAXSUCHE = (((MAXIMUM-1) div cMaxZahl+1)*cRepFldLen-1)
DIV cBitSize;
type
tRpFldIdx = 0..cRepFldLen-1;
pNativeUint = ^ NativeUint;
(* numberField as Bit array *)
tsearchFld = array of tSievenum;
tSegment = record
dOfs,
dSegment :tSievenum;
end;
tpSegment = ^tSegment;
tMulFeld = array [0..MaxMulFac shr 1 -1] of tSegment;
tnumberField= array [0..cMaxZahl-1] of word; //word-> 0..cRepFldLen-1
tRevIdx = array [tRpFldIdx] of word;//word-> 0..cMaxZahl-1
tDiffFeld = array [tRpFldIdx] of byte;
tNewPosFeld = array [tRpFldIdx] of Uint64;
tRecPrime = record
rpPrime,
rpsvPos : Uint64;
rpOfs,
rpSeg :LongWord;
end;
var
BitSet,
BitClr : Array [0..cAndMask] Of NativeUint;
deltaNewPos : tNewPosFeld;
MulFeld : tMulFeld;
searchFld : tsearchFld;
number : tnumberField;
DiffFld : tDiffFeld;
RevIdx : tRevIdx;
actSquare : Uint64;
NewStartPos,
MaxPos : Uint64;
const
//K1 = $0101010101010101;
K55 = $5555555555555555;
K33 = $3333333333333333;
KF1 = $0F0F0F0F0F0F0F0F;
KF2 = $00FF00FF00FF00FF;
KF4 = $0000FFFF0000FFFF;
KF8 = $00000000FFFFFFFF;
function popcnt(n:Uint64):integer;overload;inline;
var
c,b,k : NativeUint;
begin
b := n;
k := NativeUint(K55);c := (b shr 1) AND k; b := (b AND k)+C;
k := NativeUint(K33);c := ((b shr 2) AND k);b := (b AND k)+C;
k := NativeUint(KF1);c := ((b shr 4) AND k);b := (b AND k)+c;
k := NativeUint(KF2);c := ((b shr 8) AND k);b := (b AND k)+c;
k := NativeUint(KF4);c := ((b shr 16) AND k);b := (b AND k)+c;
k := NativeUint(KF8);c := (b shr 32)+(b AND k);
result := c;
end;
function popcnt(n:LongWord):integer;overload;
var
c,k : LongWord;
begin
result := n;
IF result = 0 then
EXIT;
k := LongWord(K55);c := (result shr 1) AND k; result := (result AND k)+C;
k := LongWord(K33);c := ((result shr 2) AND k);result := (result AND k)+C;
k := LongWord(KF1);c := ((result shr 4) AND k);result := (result AND k)+c;
k := LongWord(KF2);c := ((result shr 8) AND k);result := (result AND k)+c;
k := LongWord(KF4);
result := (result shr 16) AND k +(result AND k);
end;
procedure Init;
{simple sieve of erathosthenes only eliminating small primes}
var
pr,i,j,Ofs : NativeUint;
Begin
//Init Bitmasks
j := 1;
For i := 0 to cAndMask do
Begin
BitSet[i] := J;
BitClr[i] := NativeUint(NOT(J));
j:= j+j;
end;
//building number wheel excluding multiples of small primes
Fillchar(number,SizeOf(number),#0);
For i := 0 to BIS do
Begin
pr := InitPrim[i];
j := (High(number) div pr)*pr;
repeat
number[j] := 1;
dec(j,pr);
until j <= 0;
end;
// build reverse Index and save distances
i := 1;
j := 0;
RevIdx[0]:= 1;
repeat
Ofs :=0;
repeat
inc(i);
inc(ofs);
until number[i] = 0;
DiffFld[j] := ofs;
inc(j);
RevIdx[j] := i;
until i = High(number);
DiffFld[j] := 2;
//calculate a bitnumber-index into cRepFldLen
Fillchar(number,SizeOf(number),#0);
Ofs := 1;
for i := 0 to cRepFldLen-2 do
begin
inc(Ofs,DiffFld[i]);
number[ofs] := i+1;
end;
//direct index into Mulfeld 2->0 ,4-> 1 ...
For i := 0 to cRepFldLen-1 do
Begin
j := (DiffFld[i] shr 1) -1;
DiffFld[i] := j;
end;
end;
function CalcPos(m: Uint64): Uint64;
{search right position of m}
var
i,res : NativeUint;
Begin
res := m div cMaxZahl;
i := m-res* Uint64(cMaxzahl);//m mod cMaxZahl
while (number[i]= 0) and (i <>1) do
begin
iF i = 0 THEN
begin
Dec(res,cRepFldLen);
i := cMaxzahl;
end;
dec(i);
end; {while}
CalcPos := res *Uint64(cRepFldLen) +number[i];
end;
procedure CalcSqrOfs(out Segment,Ofs :Uint64);
Begin
Segment := actSquare div cMaxZahl;
Ofs := actSquare-Segment*cMaxZahl; //ofs Mod cMaxZahl
Segment := Segment*cRepFldLen;
end;
procedure MulTab(sievePr:Nativeint);
var
k,Segment,Segment0,Rest,Rest0: NativeUint;
Begin
{multiplication-table of differences}
{2* sievePr,4* ,6* ...MaxMulFac*sievePr }
sievePr := sievePr+sievePr;
Segment0 := sievePr div cMaxzahl;
Rest0 := sievePr-Segment0*cMaxzahl;
Segment0 := Segment0 * cRepFldLen;
Segment := Segment0;
Rest := Rest0;
with MulFeld[0] do
begin
dOfs := Rest0;
dSegment:= Segment0;
end;
for k := 1 to MaxMulFac shr 1-1 do
begin
Segment := Segment+Segment0;
Rest := Rest+Rest0;
IF Rest >= cMaxzahl then
Begin
Rest:= Rest-cMaxzahl;
Segment := Segment+cRepFldLen;
end;
with MulFeld[k] do
begin
dOfs := Rest;
dSegment:= Segment;
end;
end;
end;
procedure CalcDeltaNewPos(sievePr,MulPos:NativeUint);
var
Ofs,Segment,prevPos,actPos : Uint64;
i: NativeInt;
Begin
MulTab(sievePr);
//start at sqr sievePrime
CalcSqrOfs(Segment,Ofs);
NewStartPos := Segment+number[Ofs];
prevPos := NewStartPos;
deltaNewPos[0]:= prevPos;
For i := 0 to cRepFldLen-2 do
begin
inc(mulpos);
IF mulpos >= cRepFldLen then
mulpos := 0;
With MulFeld[DiffFld[mulpos]] do
begin
Ofs:= Ofs+dOfs;
Segment := Segment+dSegment;
end;
If Ofs >= cMaxZahl then
begin
Ofs := Ofs-cMaxZahl;
Segment := Segment+cRepFldLen;
end;
actPos := Segment+number[Ofs];
deltaNewPos[i]:= actPos - prevPos;
IF actPos> maxPos then
BREAK;
prevPos := actPos;
end;
deltaNewPos[cRepFldLen-1] := NewStartPos+cRepFldLen*sievePr-prevPos;
end;
procedure SieveByOnePrime(var sf:tsearchFld;sievePr:NativeUint);
var
pNewPos : ^Uint64;
pSiev0,
pSiev : ^tSievenum;// dynamic arrays are slow
Ofs : Int64;
Position : UINt64;
i: NativeInt;
Begin
pSiev0 := @sf[0];
Ofs := MaxPos-sievePr *cRepFldLen;
Position := NewStartPos;
{unmark multiples of sieve prime}
repeat
IF Position < Ofs then
Begin
pNewPos:= @deltaNewPos[0];
For i := Low(deltaNewPos) to High(deltaNewPos) do
Begin
pSiev := pSiev0;
inc(pSiev,Position DIV cBitSize);
//pSiev^ == @sf[Position DIV cBitSize]
pSiev^ := pSiev^ AND BitCLR[Position AND cAndMask];
inc(Position,pNewPos^);
inc(pNewPos);
end
end
else
Begin
pNewPos:= @deltaNewPos[0];
For i := Low(deltaNewPos) to High(deltaNewPos) do
Begin
IF Position >= MaxPos then
Break;
pSiev := pSiev0;
inc(pSiev,Position DIV cBitSize);
pSiev^ := pSiev^ AND BitCLR[Position AND cAndMask];
inc(Position,pNewPos^);
inc(pNewPos);
end
end;
until Position >= MaxPos;
end;
procedure SieveAll;
var
i,
sievePr,
PrimPos,
srPrPos : NativeUint;
Begin
Init;
MaxPos := CalcPos(MaxUpperLimit);
{start of prime sieving}
i := (MaxPos-1) DIV cBitSize+1;
setlength(searchFld,i);
IF Length(searchFld) <> i then
Begin
writeln('Not enough memory');
Halt(-227);
end;
For i := High(searchFld) downto 0 do
searchFld[i] := NativeUint(-1);
{the first prime}
srPrPos := 0;
PrimPos := 0;
sievePr := 1;
actSquare := sievePr;
repeat
{next prime}
inc(srPrPos);
i := 2*(DiffFld[PrimPos]+1);
//binom (a+b)^2; a^2 already known
actSquare := actSquare+(2*sievePr+i)*i;
inc(sievePr,i);
IF actSquare > MaxUpperLimit THEN
BREAK;
{if sievePr == prime then sieve with sievePr}
if BitSet[srPrPos AND cAndMask] AND
searchFld[srPrPos DIV cBitSize] <> 0then
Begin
write(sievePr:8,#8#8#8#8#8#8#8#8);
CalcDeltaNewPos(sievePr,PrimPos);
SieveByOnePrime(searchFld,sievePr);
end;
inc(PrimPos);
if PrimPos = cRepFldLen then
dec(PrimPos,PrimPos);// := 0;
until false;
end;
function InitRecPrime(pr: UInt64):tRecPrime;
var
svPos,sg : NativeUint;
Begin
svPos := CalcPos(pr);
sg := svPos DIV cRepFldLen;
with result do
Begin
rpsvPos := svPos;
rpSeg := sg;
rpOfs := svPos - sg*cRepFldLen;
rpPrime := RevIdx[rpOfs]+ sg*cMaxZahl;
end;
end;
function InitPrimeSvPos(svPos: Uint64):tRecPrime;
var
sg : LongWord;
Begin
sg := svPos DIV cRepFldLen;
with result do
Begin
rpsvPos := svPos;
rpSeg := sg;
rpOfs := svPos - sg*cRepFldLen;
rpPrime := RevIdx[rpOfs]+ sg*cMaxZahl;
end;
end;
function NextPrime(var pr: tRecPrime):Boolean;
var
ofs : LongWord;
svPos : Uint64;
Begin
with pr do
Begin
svPos := rpsvPos;
Ofs := rpOfs;
repeat
inc(svPos);
if svPos > MaxPos then
Begin
result := false;
EXIT;
end;
inc(Ofs);
IF Ofs >= cRepFldLen then
Begin
ofs := 0;
inc(rpSeg);
end;
until BitSet[svPos AND cAndMask] AND
searchFld[svPos DIV cBitSize] <> 0;
rpPrime := rpSeg*Uint64(cMaxZahl)+RevIdx[Ofs];
rpSvPos := svPos;
rpOfs := Ofs;
end;
result := true;
end;
function GetNthPrime(n: Uint64):tRecPrime;
var
i : longWord;
cnt: Uint64;
Begin
IF n > MaxPos then
EXIT;
i := 0;
cnt := Bis;
For i := 0 to n DIV cBitSize do
inc(cnt,PopCnt(NativeUint(searchFld[i])));
i := n DIV cBitSize+1;
while cnt < n do
Begin
inc(cnt,PopCnt(NativeUint(searchFld[i])));
inc(i);
end;
dec(i);
dec(cnt,PopCnt(NativeUint(searchFld[i])));
result := InitPrimeSvPos(i*Uint64(cBitSize)-1);
while cnt < n do
IF NextPrime(Result) then
inc(cnt)
else
Break;
end;
procedure ShowPrimes(loLmt,HiLmt: NativeInt);
var
p1 :tRecPrime;
Begin
IF HiLmt < loLmt then
exit;
p1 := InitRecPrime(loLmt);
while p1.rpPrime < LoLmt do
IF Not(NextPrime(p1)) Then
EXIT;
repeat
write(p1.rpPrime,' ');
IF Not(NextPrime(p1)) Then
Break;
until p1.rpPrime > HiLmt;
writeln;
end;
function CountPrimes(loLmt,HiLmt: NativeInt):LongWord;
var
p1 :tRecPrime;
Begin
result := 0;
IF HiLmt < loLmt then
exit;
p1 := InitRecPrime(loLmt);
while p1.rpPrime < LoLmt do
IF Not(NextPrime(p1)) Then
EXIT;
repeat
inc(result);
IF Not(NextPrime(p1)) Then
Break;
until p1.rpPrime > HiLmt;
end;
procedure WriteCntSmallPrimes(n: NativeInt);
var
i, p,prPos,svPos : nativeUint;
Begin
dec(n);
IF n < 0 then
EXIT;
write('First ',n+1,' primes ');
IF n < Bis then
Begin
For i := 0 to n do
write(InitPrim[i]:3);
end
else
Begin
For i := 0 to BIS do
write(InitPrim[i],' ');
dec(n,Bis);
svPos := 0;
PrPos := 0;
p := 1;
while n> 0 do
Begin
{next prime}
inc(svPos);
inc(p,2*(DiffFld[prPos]+1));
if BitSet[svPos AND cAndMask] AND searchFld[svPos DIV cBitSize] <>0 then
Begin
write(p,' ');
dec(n);
end;
inc(prPos);
if prPos = cRepFldLen then
dec(prPos,prPos);// := 0;
end;
end;
writeln;
end;
function RvsNumL(var n: Uint64):Uint64;
//reverse and last digit, most of the time n > base therefor repeat
const
base = 10;
var
q, c: Int64;
Begin
result := n;
q := 0;
repeat
c:= result div Base;
q := result+ (q-c)*Base;
result := c;
until result < Base;
n := q*Base+result;
end;
function IsEmirp(n:Uint64):boolean;
var
lastDgt:NativeUint;
ofs: NativeUint;
seg : Uint64;
Begin
seg := n;
lastDgt:= RvsNumL(n);
result:= false;
IF (seg = n) OR (n> MaxUpperLimit) then
EXIT;
IF lastDgt in [1,3,7,9] then
Begin
seg := n div cMaxZahl;
ofs := n-seg* cMaxzahl;//m mod cMaxZahl
IF (Number[ofs] <> 0) OR (ofs=1) then
begin
seg := seg *cRepFldLen+number[ofs];
result := BitSet[seg AND cAndMask] AND searchFld[seg DIV cBitSize] <> 0;
end
end;
end;
function GetEmirps(loLmt,HiLmt: Uint64):NativeInt;
var
p1 :tRecPrime;
Begin
result := 0;
IF HiLmt < loLmt then
exit;
IF loLmt > MaxUpperLimit then
Exit;
IF HiLmt > MaxUpperLimit then
HiLmt := MaxUpperLimit;
p1 := InitRecPrime(loLmt);
while p1.rpPrime < LoLmt do
IF Not(NextPrime(p1)) Then
EXIT;
repeat
if isEmirp(p1.rpPrime) then
inc(result);
iF not(NextPrime(p1)) then
BREAK;
until p1.rpPrime > HiLmt;
end;
var
T1,T0: TDateTime;
Anzahl :Uint64;
i,j,dgtCnt,totalCnt : Uint64;
n : LongInt;
Begin
T0 := now;
SieveAll;
T1 := now;
writeln(' ');
Writeln('time for sieving ',FormatDateTime('NN:SS.ZZZ',T1-T0));
Anzahl := BIS;
For n := MaxPos DIV cBitSize-1 downto 0 do
inc(Anzahl,PopCnt(NativeUint(searchFld[n])));
n := MaxPos AND cAndMask;
IF n >0 then
Begin
dec(n);
repeat
IF BitSet[n] AND searchFld[MaxPos DIV cBitSize] <> 0 then
inc(Anzahl);
dec(n);
until n< 0;
end;
Writeln('there are ',Anzahl,' primes til ',MaxUpperLimit);
WriteCntSmallPrimes(20);
write('primes between 100 and 150: ');
ShowPrimes(100,150);
write('count of primes between 7700 and 8000 ');
Writeln(CountPrimes(7700,8000));
i := 100;
repeat
Writeln('the ',i, ' th prime ',GetNthPrime(i).rpPrime);
i := i * 10;
until i*25 > MaxUpperLimit;
writeln;
writeln('Count Emirps');
writeln(' Emirp Total');
writeln('Decimals Count Count');
totalCnt := 0;
j := 10;
i := 2;
dgtCnt := 2; // 13 is not present so 13<->31 isnt found
repeat
write(i:8);
inc(dgtCnt,GetEmirps( j, j+j-1));//10..00->19..99
inc(dgtCnt,GetEmirps(3*j,3*j+j-1));//30..00->39..99
inc(dgtCnt,GetEmirps(7*j,7*j+j-1));//70..00->79..99
inc(dgtCnt,GetEmirps(9*j,9*j+j-1));//90..00->99..99
inc(TotalCnt,dgtCnt);
writeln(dgtCnt:12,TotalCnt:14);
j:=j*10;
inc(i);
dgtCnt := 0;
until j >= MaxUpperLimit;
end.

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@ -0,0 +1,9 @@
use Math::Prime::Util qw(nth_prime prime_count primes);
# Direct solutions.
# primes([start],end) returns an array reference with all primes in the range
# prime_count([start],end) uses sieving or LMO to return fast prime counts
# nth_prime(n) does just that. It runs quite fast for native size inputs.
say "First 20: ", join(" ", @{primes(nth_prime(20))});
say "Between 100 and 150: ", join(" ", @{primes(100,150)});
say prime_count(7700,8000), " primes between 7700 and 8000";
say "${_}th prime: ", nth_prime($_) for map { 10**$_ } 1..8;

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@ -0,0 +1,12 @@
use Math::Prime::Util "prime_iterator_object";
my $it = prime_iterator_object;
say "First 20: ", join(" ", map { $it->iterate() } 1..20);
$it->seek_to_value(100);
print "Between 100 and 150:";
print " ", $it->iterate() while $it->value() <= 150;
print "\n";
$it->seek_to_value(7700);
my $c = 0;
$c++ while $it->iterate() <= 8000;
say "$c primes between 7700 and 8000";
say "${_}th prime: ", $it->ith($_) for map { 10**$_ } 1..8;

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@ -0,0 +1,13 @@
use Math::Prime::Util qw/forprimes/;
use Math::Prime::Util::PrimeArray;
tie my @primes, 'Math::Prime::Util::PrimeArray';
say "First 20: @primes[0..19]"; # Slice from the tied array
print "Between 100 and 150: "; forprimes { print " $_"; } 100,150; print "\n";
# Count with forprimes
my $c = 0;
forprimes { $c++ } 7700,8000;
print "$c primes between 7700 and 8000\n";
# The tied array tries to do the right thing -- sieve a window if it sees
# forward or backward iteration, and nth_prime if it looks like random access.
say "${_}th prime: ", $primes[$_-1] for map { 10**$_ } 1..8;

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@ -0,0 +1,5 @@
use bigint;
use Math::Prime::Util qw/forprimes prime_get_config/;
warn "No GMP, expect slow results\n" unless prime_get_config->{gmp};
my $n = 10**200;
forprimes { say $_-$n } $n,$n+1000;

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@ -0,0 +1,64 @@
(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span> <span style="color: #7060A8;">free_console</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">primes</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,</span><span style="color: #000000;">7</span><span style="color: #0000FF;">}</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">sieved</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">10</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">add_block</span><span style="color: #0000FF;">()</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">N</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">min</span><span style="color: #0000FF;">((</span><span style="color: #000000;">sieved</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">sieved</span><span style="color: #0000FF;">,</span><span style="color: #000000;">400000</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">sieve</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">N</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- sieve[i] is really i+sieved</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">2</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span> <span style="color: #000080;font-style:italic;">-- (evens filtered on output)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">primes</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">],</span> <span style="color: #000000;">p2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">*</span><span style="color: #000000;">p</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">p2</span><span style="color: #0000FF;">></span><span style="color: #000000;">sieved</span><span style="color: #0000FF;">+</span><span style="color: #000000;">N</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">p2</span><span style="color: #0000FF;"><</span><span style="color: #000000;">sieved</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">p2</span> <span style="color: #0000FF;">+=</span> <span style="color: #7060A8;">ceil</span><span style="color: #0000FF;">((</span><span style="color: #000000;">sieved</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">p2</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">p</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">p</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">p2</span> <span style="color: #0000FF;">-=</span> <span style="color: #000000;">sieved</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">and_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">p2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #000000;">p2</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">p</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000080;font-style:italic;">-- if sieve[p2] then -- dang!</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #000000;">p2</span> <span style="color: #008080;">to</span> <span style="color: #000000;">N</span> <span style="color: #008080;">by</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">*</span><span style="color: #000000;">2</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">sieve</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000080;font-style:italic;">-- end if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">N</span> <span style="color: #008080;">by</span> <span style="color: #000000;">2</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">sieve</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">primes</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">sieved</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000000;">sieved</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">N</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">is_prime2</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">while</span> <span style="color: #000000;">sieved</span><span style="color: #0000FF;"><</span><span style="color: #000000;">n</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">add_block</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #008080;">return</span> <span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">)></span><span style="color: #000000;">0</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">t0</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">time</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">while</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">)<</span><span style="color: #000000;">20</span> <span style="color: #008080;">do</span> <span style="color: #000000;">add_block</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first 20 primes are: "</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">?</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..</span><span style="color: #000000;">20</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">while</span> <span style="color: #000000;">sieved</span><span style="color: #0000FF;"><</span><span style="color: #000000;">150</span> <span style="color: #008080;">do</span> <span style="color: #000000;">add_block</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">=</span><span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">binary_search</span><span style="color: #0000FF;">(</span><span style="color: #000000;">100</span><span style="color: #0000FF;">,</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">))</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">p</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">primes</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">p</span><span style="color: #0000FF;">></span><span style="color: #000000;">150</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">s</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">p</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The primes between 100 and 150 are: "</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">?</span><span style="color: #000000;">s</span>
<span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">7700</span> <span style="color: #008080;">to</span> <span style="color: #000000;">8000</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">is_prime2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">&=</span><span style="color: #000000;">i</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %d primes between 7700 and 8000.\n"</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">))</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()=</span><span style="color: #004600;">JS</span><span style="color: #0000FF;">?</span><span style="color: #000000;">7</span><span style="color: #0000FF;">:</span><span style="color: #000000;">8</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">power</span><span style="color: #0000FF;">(</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">while</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">)<</span><span style="color: #000000;">k</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">add_block</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The %,dth prime is : %d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #000000;">primes</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">{}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">wait_key</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<!--

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@ -0,0 +1,15 @@
(phixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">t0</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">time</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The first 20 primes are: %v\n"</span><span style="color: #0000FF;">,{</span><span style="color: #7060A8;">get_primes</span><span style="color: #0000FF;">(-</span><span style="color: #000000;">20</span><span style="color: #0000FF;">)})</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">get_primes_le</span><span style="color: #0000FF;">(</span><span style="color: #000000;">150</span><span style="color: #0000FF;">)[</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">get_primes_le</span><span style="color: #0000FF;">(</span><span style="color: #000000;">100</span><span style="color: #0000FF;">))+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..$]</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The primes between 100 and 150 are: %v\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">s</span><span style="color: #0000FF;">})</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">n7700to8000</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">get_primes_le</span><span style="color: #0000FF;">(</span><span style="color: #000000;">8000</span><span style="color: #0000FF;">))-</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">get_primes_le</span><span style="color: #0000FF;">(</span><span style="color: #000000;">7700</span><span style="color: #0000FF;">))</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"There are %d primes between 7700 and 8000.\n"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n7700to8000</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()=</span><span style="color: #004600;">JS</span><span style="color: #0000FF;">?</span><span style="color: #000000;">7</span><span style="color: #0000FF;">:</span><span style="color: #000000;">8</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">power</span><span style="color: #0000FF;">(</span><span style="color: #000000;">10</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The %,dth prime is : %d\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #7060A8;">get_prime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">)})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">{}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">wait_key</span><span style="color: #0000FF;">()</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<!--

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(de prime? (N Lst)
(let S (sqrt N)
(for D Lst
(T (> D S) T)
(T (=0 (% N D)) NIL) ) ) )
(de primeseq (A B)
(let (I 1 R)
(nth
(make
(link 2)
(while (> A (inc 'I 2))
(and (prime? I (made)) (link I)) )
(setq R (length (made)))
(while (> B I)
(and (prime? I (made)) (link I))
(inc 'I 2) ) )
(inc R) ) ) )
(de take (N)
(let I 1
(make
(link 2)
(do (dec N)
(until (prime? (inc 'I 2) (made)))
(link I) ) ) ) )
(prin "First 20 primes: ")
(println (take 20))
(prin "Primes between 100 and 150: ")
(println (primeseq 100 150))
(prinl
"Number of primes between 7700 and 8000: "
(length (primeseq 7700 8000)) )
(for N (10 100 1000 10000 100000 1000000)
(prinl
N
"th prime: "
(last (take N)) ) )

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(load "plcommon/pairing-heap.l") # Pairing heap from RC task "Priority Queue"
(setq *WHEEL-2357*
(10 2 4 2 4 6 2 6
4 2 4 6 6 2 6 4
2 6 4 6 8 4 2 4
2 4 8 6 4 6 2 4
6 2 6 6 4 2 4 6
2 6 4 2 4 2 10 2 .))
(de "prime?" (N Primes)
(let S (sqrt N)
(for P Primes
(T (> P S) T)
(T (=0 (% N P)) NIL))))
(de "adjust-heap" (N H)
(while (= (caar H) N)
(let (
Wheel (cadar H)
P (cddar H)
)
(setq H
(heap-insert
(cons
(+ N (* P (car Wheel)))
(cdr Wheel)
P)
(heap-rest H)))))
H)
(de primes (Run?)
(if (not Run?)
(co 'primegen) # stop
(co 'primegen
(yield 2)
(yield 3)
(yield 5)
(yield 7)
(let (
P 11
Q 121
Wp (cdr *WHEEL-2357*)
N P
Wn (cdr *WHEEL-2357*)
H (heap-insert (cons Q Wp P) NIL)
)
(make
(link P)
(loop
(cond
((= N (caar H))
(setq H ("adjust-heap" N H))
(inc 'N (pop 'Wn)))
((< N Q)
(yield N)
(inc 'N (pop 'Wn)))
(T
(loop
(inc 'P (pop 'Wp))
(T ("prime?" P (made))))
(link P)
(setq
Q (* P P)
H (heap-insert (cons Q Wp P) H))))))))))

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@ -0,0 +1,28 @@
(prin "The first 20 primes: ")
(do 20 (printsp (primes T)))
(prinl)
(prin "between 100 and 150: ")
(while (< (setq P (primes T)) 150)
(when (> P 100)
(printsp P)))
(prinl)
(setq Count 0)
(while (< (setq P (primes T)) 8000)
(when (> P 7700)
(inc 'Count)))
(prinl "There are " Count " primes between 7700 and 8000.")
(de nthprime (N)
(primes NIL)
(do (dec N)
(primes T))
(primes T))
(de comma_fmt (N) (format N 0 "." ","))
(prinl "nth prime:")
(for N (10 100 1000 10000 100000 1000000)
(prinl (align 9 (comma_fmt N)) " " (align 12 (comma_fmt (nthprime N)))))
(bye)

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EnableExplicit
DisableDebugger
Define StartTime.i=ElapsedMilliseconds()
Procedure.b IsPrime(n.i)
Define i.i=5
If n<2 : ProcedureReturn #False : EndIf
If n%2=0 : ProcedureReturn Bool(n=2) : EndIf
If n%3=0 : ProcedureReturn Bool(n=3) : EndIf
While i*i<=n
If n%i=0 : ProcedureReturn #False : EndIf
i+2
If n%i=0 : ProcedureReturn #False : EndIf
i+4
Wend
ProcedureReturn #True
EndProcedure
If OpenConsole("Extensible prime generator")
Define c.i=0, n.i=2
Print("First twenty: ")
While c<20
If IsPrime(n)
Print(Str(n)+" ")
c+1
EndIf
n+1
Wend
Print(~"\nBetween 100 and 150: ")
For n=100 To 150
If IsPrime(n)
Print(Str(n)+" ")
EndIf
Next
Print(~"\nNumber beween 7'700 and 8'000: ")
c=0
For n=7700 To 8000
c+IsPrime(n)
Next
Print(Str(c))
Print(~"\n10'000th prime: ")
c=0 : n=1
While c<10000
n+1
c+IsPrime(n)
Wend
Print(Str(n))
EndIf
Print(~"\nRuntime milliseconds: "+
Str(ElapsedMilliseconds()-StartTime))
Input()

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@ -0,0 +1 @@
islice(count(7), 0, None, 2)

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from __future__ import print_function
from prime_decomposition import primes
from itertools import islice
def p_range(lower_inclusive, upper_exclusive):
'Primes in the range'
for p in primes():
if p >= upper_exclusive: break
if p >= lower_inclusive: yield p
if __name__ == '__main__':
print('The first twenty primes:\n ', list(islice(primes(),20)))
print('The primes between 100 and 150:\n ', list(p_range(100, 150)))
print('The ''number'' of primes between 7,700 and 8,000:\n ', len(list(p_range(7700, 8000))))
print('The 10,000th prime:\n ', next(islice(primes(),10000-1, 10000)))

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def wsieve(): # ideone.com/mqO25A
wh11 = [ 2,4,2,4,6,2,6,4,2,4,6,6, 2,6,4,2,6,4,6,8,4,2,4,2,
4,8,6,4,6,2,4,6,2,6,6,4, 2,4,6,2,6,4,2,4,2,10,2,10 ]
cs = accumulate(chain([11], cycle(wh11)))
yield next(cs) # cf. ideone.com/WFv4f
ps = wsieve() # codereview.stackexchange.com/q/92365/9064
p = next(ps) # 11 stackoverflow.com/q/30553925/849891
psq = p*p # 121
D = dict(zip( accumulate(chain([0], wh11)), count(0) )) # start from
mults = {}
for c in cs:
if c in mults:
wheel = mults.pop(c)
elif c < psq:
yield c
continue
else: # c==psq: map (p*) (roll wh from p) = roll (wh*p) from (p*p)
x = [p*d for d in wh11]
i = D[(p-11) % 210]
wheel = accumulate(chain([psq+x[i]], cycle(x[i+1:] + x[:i+1])))
p = next(ps)
psq = p*p
for m in wheel:
if not m in mults:
break
mults[m] = wheel
def primes():
yield from (2, 3, 5, 7)
yield from wsieve()
print( list( islice( primes(), 0, 20)))
print( list( takewhile( lambda x: x<150,
dropwhile( lambda x: x<100, primes()))))
print( len( list( takewhile( lambda x: x<8000,
dropwhile( lambda x: x<7700, primes())))))
print( next( islice( primes(), 10000-1, 10000)))

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from itertools import count, takewhile, islice
def prime_sieve():
sieved = count(2)
prime = next(sieved)
yield prime
primes = [prime]
for x in sieved:
possible_prime_divs = takewhile(lambda p: p <= x**0.5, primes)
if any(x % prime == 0 for prime in possible_prime_divs):
continue
yield x
primes.append(x)
if __name__ == '__main__':
def leq_150(x): return x <= 150
def leq_8000(x): return x <= 8000
print("Show the first twenty primes.\n =",
list(islice(prime_sieve(), 20)))
print("Show the primes between 100 and 150\n =",
[x for x in takewhile(leq_150, prime_sieve()) if x >= 100])
print("Show the number of primes between 7,700 and 8,000.\n =",
sum(1 for x in takewhile(leq_8000, prime_sieve()) if x >= 7700))
print("Show the 10,000th prime.\n =",
next(islice(prime_sieve(), 10000-1, 10000)))

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/*REXX program calculates and displays primes using an extendible prime number generator*/
parse arg f .; if f=='' then f= 20 /*allow specifying number for 1 ──► F.*/
_i= ' (inclusive) '; _b= 'between '; _tnp= 'the number of primes' _b; _tn= 'the primes'
call primes f; do j=1 for f; $= $ @.j; end /*j*/
say 'the first ' f " primes are: " $
say
call primes -150; do j=100 to 150; if !.j==1 then $= $ j; end /*j*/
say _tn _b '100 to 150' _i "are: " $
say
call primes -8000; do j=7700 to 8000; if !.j==1 then $= $ j; end /*j*/
say _tnp '7,700 and 8,000' _i "is: " words($)
say
call primes 10000
say 'the 10,000th prime is: ' @.10000
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
primes: procedure expose !. @. $ #; parse arg H,,$; Hneg= H<0; H= abs(H)
if symbol('#')=="LIT" then call .primI /*1st time here? Then initialize stuff*/
if Hneg then if H<=@.# then return /*do we have a high enough P already?*/
else nop /*this is used to match the above THEN.*/
else if H<=# then return /*are there enough primes currently ? */
/* [↓] gen more primes within range. */
do j=@.#+2 by 2; parse var j '' -1 _ /*find primes until have H Primes. */
if _==5 then iterate /*is the right─most digit a 5 (five)? */
if j// 3==0 then iterate /*is J divisible by three? (& etc.)*/
if j// 7==0 then iterate; if j//11==0 then iterate; if j//13==0 then iterate
if j//17==0 then iterate; if j//19==0 then iterate; if j//23==0 then iterate
if j//29==0 then iterate; if j//31==0 then iterate; if j//37==0 then iterate
if j//41==0 then iterate; if j//43==0 then iterate; if j//47==0 then iterate
if j//53==0 then iterate; if j//59==0 then iterate; if j//61==0 then iterate
if j//67==0 then iterate; if j//71==0 then iterate; if j//73==0 then iterate
if j//79==0 then iterate; if j//83==0 then iterate; if j//89==0 then iterate
if j//97==0 then iterate; if j//101==0 then iterate; if j//103==0 then iterate
x= j; r= 0; q= 1; do while q<=x; q= q*4; end /*R: the sqrt(J).*/
do while q>1; q=q%4; _=x-r-q; r=r%2; if _>=0 then do;x=_;r=r+q; end; end
do k=@.lowP while @.k<=r /*÷ by the known odd primes (hardcoded)*/
if j//@.k==0 then iterate j /*J ÷ by a prime? Then not prime. ___*/
end /*k*/ /* [↑] divide by odd primes up to √ J */
#= # + 1 /*bump the number of primes found. */
@.#= j; !.j= 1 /*assign to sparse array; prime²; P#.*/
if Hneg then if H<=@.# then leave /*is this a high enough prime? */
else nop /*used to match the above THEN. */
else if H<=# then leave /*have enough primes been generated? */
end /*j*/ /* [↑] keep generating until enough. */
return /*return to invoker with more primes. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
.primI: !.=0; @.=0; /*!.x= a prime or not; @.n= Nth prime.*/
L= 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 101 103
do #=1 for words(L); p= word(L, #); @.#= p; !.p=1; end /*#*/
#= # - 1; @.lowP= #; return /*#: # primes; @.lowP: start of ÷ */

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#lang racket
;; Using the prime functions from:
(require math/number-theory)
(displayln "Show the first twenty primes.")
(next-primes 1 20)
(displayln "Show the primes between 100 and 150.")
;; Note that in each of the in-range filters I "add1" to the stop value, so that (in this case) 150 is
;; considered. I'm pretty sure it's not prime... but technology moves so fast nowadays that things
;; might have changed!
(for/list ((i (sequence-filter prime? (in-range 100 (add1 150))))) i)
(displayln "Show the number of primes between 7,700 and 8,000.")
;; (for/sum (...) 1) counts the values in a sequence
(for/sum ((i (sequence-filter prime? (in-range 7700 (add1 8000))))) 1)
(displayln "Show the 10,000th prime.")
(nth-prime (sub1 10000)) ; (nth-prime 0) => 2
;; If a languages in-built prime generator is extensible or is guaranteed to generate primes up to a
;; system limit, (2^31 or memory overflow for example), then this may be used as long as an
;; explanation of the limits of the prime generator is also given. (Which may include a link
;; to/excerpt from, language documentation).
;;
;; Full details in:
;; [[http://docs.racket-lang.org/math/number-theory.html?q=prime%3F#%28part._primes%29]]
;; When reading the manual, note that "Integer" and "Natural" are unlimited (or bounded by whatever
;; big number representation there is (and the computational complexity of the work being asked).
(define 2^256 (expt 2 256))
2^256
(next-prime 2^256)
;; (Oh, and this is a 64-bit laptop, I left my 256-bit PC in the office.)

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my @primes = lazy gather for 1 .. * { .take if .is-prime }
say "The first twenty primes:\n ", "[{@primes[^20].fmt("%d", ', ')}]";
say "The primes between 100 and 150:\n ", "[{@primes.&between(100, 150).fmt("%d", ', ')}]";
say "The number of primes between 7,700 and 8,000:\n ", +@primes.&between(7700, 8000);
say "The 10,000th prime:\n ", @primes[9999];
sub between (@p, $l, $u) {
gather for @p { .take if $l < $_ < $u; last if $_ >= $u }
}

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Red [Description: "Prime checker/generator/counter"]
context [
poke noprime: make bitset! 3 1 true
top: 2
noprimes: function [n [integer!] /extern top][
either top < n [
n: n + 100
r: 2
while [r * r <= n][
repeat q n / r - 1 [poke noprime q + 1 * r true]
until [not pick noprime r: r + 1]
]
self/top: n
][top]
]
set 'prime? func [
"Check whether number is prime or return required prime"
n [integer!]
/next "Return next closest prime to given number"
/last "Return last closest prime to given number, or number itself if prime"
/Nth "Return Nth prime"
][
noprimes case [
Nth [to integer! n * 12 ]
next [n + 100]
true [n]
]
case [
next [until [not noprime/(n: n + 1)] n]
last [while [noprime/:n][n: n - 1] n]
Nth [
cnt: i: 0
while [cnt < n][
until [not noprime/(i: i + 1)]
cnt: cnt + 1
]
i
]
true [not noprime/:n]
]
]
set 'primes function [
"Return (number of) primes in given range"
n [integer!]
/from "Start considering primes from `start`"
start "Default 1"
/list "First argument is interpreted as number of primes to list"
/count "Count primes from `start`"
][
start: any [start 1]
either list [
noprimes start + (n * 12)
][
set [start n] sort reduce [n start]
noprimes start + n
]
case [
list [
start: start - 1
collect [
loop n [
until [not noprime/(start: start + 1)]
keep start
]
]
]
count [
cnt: 0
repeat i n - start + 1 [
j: i - 1
if not noprime/(j + start) [cnt: cnt + 1]
]
cnt
]
true [
collect [
repeat i n - start + 1 [
j: i - 1
if not noprime/(j: j + start) [keep j]
]
]
]
]
]
]

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@ -0,0 +1,38 @@
see "first twenty primes : "
i = 1
nr = 0
while i <= 20
nr += 1
if isPrime(nr) see " " + nr i += 1 ok
end
see "primes between 100 and 150 : "
for nr = 100 to 150
if isPrime(nr) see " " + nr ok
next
see nl
see "primes between 7,700 and 8,000 : "
i = 0
for nr = 7700 to 8000
if isPrime(nr) i += 1 ok
next
see i + nl
see "The 10,000th prime : "
i = 1
nr = 0
while i <= 10000
nr += 1
if isPrime(nr) i += 1 ok
end
see nr + nl
func isPrime n
if n <= 1 return false ok
if n <= 3 return true ok
if (n & 1) = 0 return false ok
for t = 3 to sqrt(n) step 2
if (n % t) = 0 return false ok
next
return true

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require "prime"
puts Prime.take(20).join(", ")
puts Prime.each(150).drop_while{|pr| pr < 100}.join(", ")
puts Prime.each(8000).drop_while{|pr| pr < 7700}.count
puts Prime.take(10_000).last

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mod pagesieve;
use pagesieve::{count_primes_paged, primes_paged};
fn main() {
println!("First 20 primes:\n {:?}",
primes_paged().take(20).collect::<Vec<_>>());
println!("Primes between 100 and 150:\n {:?}",
primes_paged().skip_while(|&x| x < 100)
.take_while(|&x| x < 150)
.collect::<Vec<_>>());
let diff = count_primes_paged(8000) - count_primes_paged(7700);
println!("There are {} primes between 7,700 and 8,000", diff);
// rust enumerations are zero base, so need to subtract 1!!!
println!("The 10,000th prime is {}", primes_paged().nth(10_000 - 1).unwrap());
}

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