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March 2014 update

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Ingy döt Net 2014-04-02 16:56:35 +00:00
parent 09687c4926
commit a25938f123
1846 changed files with 21876 additions and 5203 deletions
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19
Task/Average-loop-length/D/average-loop-length.d
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@ -1,17 +1,14 @@
import std.stdio, std.random, std.math, std.algorithm, std.range;
real analytical(in int n) pure nothrow {
real total = 0.0;
foreach (immutable k; 1 .. n + 1) {
immutable x = reduce!q{a * b}(1.0L, iota(n - k + 1, n + 1))
* k ^^ 2;
total += x / ((cast(real)n) ^^ (k + 1));
}
return total;
real analytical(in int n) /*pure nothrow*/ {
enum aux = (int k)=> reduce!q{a * b}(1.0L, iota(n - k + 1, n + 1));
return iota(1, n + 1)
.map!(k => (aux(k) * k ^^ 2) / (real(n) ^^ (k + 1)))
.sum;
}
size_t loopLength(size_t maxN)(in int size, ref Xorshift rng) {
__gshared bool[maxN + 1] seen;
__gshared static bool[maxN + 1] seen;
seen[0 .. size + 1] = false;
int current = 1;
size_t steps = 0;
@ -34,8 +31,8 @@ void main() {
long total = 0;
foreach (immutable _; 0 .. nTrials)
total += loopLength!maxN(n, rng);
immutable average = total / cast(real)nTrials;
immutable an = analytical(n);
immutable average = total / real(nTrials);
immutable an = n.analytical;
immutable percentError = abs(an - average) / an * 100;
immutable errorS = format("%2.4f", percentError);
writefln("%3d %9.5f %12.5f (%7s%%)",