Merge pull request #6308 from choroba/ech170

Solve 170: Primorial Numbers & Kronecker Product by E. Choroba

2 files changed, 90 insertions, 0 deletions

diff --git a/challenge-170/e-choroba/perl/ch-1.pl b/challenge-170/e-choroba/perl/ch-1.pl
new file mode 100755
index 0000000000..771d49feb6
--- /dev/null
+++ b/challenge-170/e-choroba/perl/ch-1.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use experimental 'signatures';
+
+use Math::Prime::Util qw{ pn_primorial };
+
+sub primorial_number ($n) {
+    pn_primorial($n)
+}
+
+use Test::More tests => 5;
+
+is primorial_number(0), 1;
+is primorial_number(1), 2;
+is primorial_number(2), 6;
+is primorial_number(3), 30;
+is primorial_number(4), 210;
diff --git a/challenge-170/e-choroba/perl/ch-2.pl b/challenge-170/e-choroba/perl/ch-2.pl
new file mode 100755
index 0000000000..6d466028d7
--- /dev/null
+++ b/challenge-170/e-choroba/perl/ch-2.pl
@@ -0,0 +1,72 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+
+use PDL;
+use PDL::NiceSlice;
+sub kronecker_product {
+    my ($x, $y) = @_;
+    my ($x0, $x1) = $x->dims;
+    my ($y0, $y1) = $y->dims;
+
+    return (
+        $y * $x->dummy(0, $y0)->dummy(1, $y1)
+    )->xchg(1, 2)->reshape($x0 * $y0, $x1 * $y1)
+}
+
+sub kron_rosetta {
+	my $A = shift;
+	my $B = shift;
+	my ($r0, $c0) = $A->dims;
+	my ($r1, $c1) = $B->dims;
+	my $kron = zeroes($r0 * $r1, $c0 * $c1);
+	for(my $i = 0; $i < $r0; ++$i){
+		for(my $j = 0; $j < $c0; ++$j){
+			$kron(
+				($i * $r1) : (($i + 1) * $r1 - 1),
+				($j * $c1) : (($j + 1) * $c1 - 1)
+			) .= $A($i,$j) * $B;
+		}
+	}
+	return $kron;
+}
+
+use Test::More tests => 4;
+
+my $A = pdl([1, 2], [3, 4]);
+my $B = pdl([5, 6], [7, 8]);
+my $AB = pdl([ 5,  6, 10, 12],
+             [ 7,  8, 14, 16],
+             [15, 18, 20, 24],
+             [21, 24, 28, 32]);
+
+is_deeply kronecker_product($A, $B), $AB;
+is_deeply kron_rosetta($A, $B), $AB;
+
+my $X = pdl([1, -4, 7], [-2, 3, 3]);
+my $Y = pdl([8, -9, -6,  5],
+            [1, -3, -4,  7],
+            [2,  8, -8, -3],
+            [1,  2, -5, -1]);
+my $XY =pdl([8, -9, -6, 5, -32, 36, 24, -20, 56, -63, -42, 35],
+            [1, -3, -4, 7, -4, 12, 16, -28, 7, -21, -28, 49],
+            [2, 8, -8, -3, -8, -32, 32, 12, 14, 56, -56, -21],
+            [1, 2, -5, -1, -4, -8, 20, 4, 7, 14, -35, -7],
+            [-16, 18, 12, -10, 24, -27, -18, 15, 24, -27, -18, 15],
+            [-2, 6, 8, -14, 3, -9, -12, 21, 3, -9, -12, 21],
+            [-4, -16, 16, 6, 6, 24, -24, -9, 6, 24, -24, -9],
+            [-2, -4, 10, 2, 3, 6, -15, -3, 3, 6, -15, -3]);
+
+is_deeply kronecker_product($X, $Y), $XY;
+is_deeply kron_rosetta($X, $Y), $XY;
+
+use Benchmark qw{ cmpthese };
+cmpthese(-3, {
+    choroba => sub { kronecker_product($X, $Y) },
+    rosetta => sub { kron_rosetta($X, $Y) }
+});
+
+__END__
+           Rate rosetta choroba
+rosetta  9509/s      --    -63%
+choroba 25377/s    167%      --