September Morn Update

Task/Arithmetic-Rational/Haskell/arithmetic-rational.hs

@@ -1,10 +1,18 @@
-import Data.Ratio
+import Data.Ratio ((%))
 
--- simply prints all the perfect numbers
-main = mapM_ print [candidate
-                   | candidate <- [2 .. 2^19],
-                     getSum candidate == 1]
-  where getSum candidate = 1 % candidate +
-                           sum [1 % factor + 1 % (candidate `div` factor)
-                               | factor <- [2 .. floor(sqrt(fromIntegral(candidate)))],
-                                 candidate `mod` factor == 0]
+-- Prints the first N perfect numbers.
+main = do
+  let n = 4
+  mapM_ print $
+    take
+      n
+      [ candidate
+      | candidate <- [2 .. 2 ^ 19]
+      , getSum candidate == 1 ]
+  where
+    getSum candidate =
+      1 % candidate +
+      sum
+        [ 1 % factor + 1 % (candidate `div` factor)
+        | factor <- [2 .. floor (sqrt (fromIntegral candidate))]
+        , candidate `mod` factor == 0 ]

Task/Arithmetic-Rational/Perl-6/arithmetic-rational-1.pl6

@@ -1,4 +1,4 @@
-for 2..2**19 -> $candidate {
+(2..2**19).hyper.map: -> $candidate {
     my $sum = 1 / $candidate;
     for 2 .. ceiling(sqrt($candidate)) -> $factor {
         if $candidate %% $factor {

Task/Arithmetic-Rational/Phix/arithmetic-rational-2.phix

@@ -0,0 +1,28 @@
+include builtins/mpfr.e
+function is_perfect(integer num)
+mpq tot = mpq_init(),
+    fth = mpq_init()
+sequence f = factors(num,1)
+    for i=1 to length(f) do
+        mpq_set_si(fth,1,f[i])
+        mpq_add(tot,tot,fth)
+    end for
+    return mpq_cmp_si(tot,2,1)=0
+end function
+
+procedure get_perfect_numbers()
+atom t0 = time()
+    for i=2 to power(2,19) do
+        if is_perfect(i) then
+            printf(1,"perfect: %d\n",i)
+        end if
+    end for
+    printf(1,"elapsed: %3.2f seconds\n",time()-t0)
+
+    integer pn5 = power(2,12)*(power(2,13)-1) -- 5th perfect number
+    if is_perfect(pn5) then
+        printf(1,"perfect: %d\n",pn5)
+    end if
+end procedure
+
+get_perfect_numbers()