Merge pull request #6247 from steve-g-lynn/new-branch

faster gmp library in ch-2.pl

1 files changed, 16 insertions, 11 deletions

diff --git a/challenge-168/steve-g-lynn/perl/ch-2.pl b/challenge-168/steve-g-lynn/perl/ch-2.pl
index 0548ac1ebc..0e7ee4acf0 100755
--- a/challenge-168/steve-g-lynn/perl/ch-2.pl
+++ b/challenge-168/steve-g-lynn/perl/ch-2.pl
@@ -1,19 +1,14 @@
 #!/usr/bin/perl
 
 #time (bash) output:
-#real	0m0.026s
-#user	0m0.019s
-#sys	0m0.007s
+#real	0m0.177s
+#user	0m0.170s
+#sys	0m0.006s
 
-# but this fast time degrades sharply with larger problems
-#
-# real is 0m45.199s if home_prime(48) also printed
-# real is 5m5.662s if home_prime of 48 and 65 also printed
-# real is 8m50.059s if home_prime of 48, 65 and 96 also printed
-#
-# probably some slowdown in factor(.) for factors of very large primes 
 
-use Math::Prime::Util qw(is_prime factor);
+use bigint;
+
+use Math::Prime::Util::GMP qw(is_prime factor); # very fast!
 
 print &home_prime(10),"\n";
 #773
@@ -24,6 +19,16 @@ print &home_prime(16),"\n";
 print &home_prime(20),"\n";
 #3318308475676071413
 
+print &home_prime(48),"\n";
+#6161791591356884791277
+
+print &home_prime(65),"\n";
+#1381321118321175157763339900357651
+
+print &home_prime(96),"\n";
+#172929671097972226356946608292031596899264419
+
+
 sub home_prime {
 	my ($n)=@_;
 	is_prime($n) && return $n;