#!/usr/bin/perl -w
#
# Title : Matrix Multiplier
# Author : Zenon Zabinski
# E-Mail : zdog7@hotmail.com
#
# Versions : 1.00 - Initial product, pun intended
# 1.10 - With several optimizations
#
# Help : When prompted for each matrix, enter each row of the matr
+ix
# followed by an <ENTER> with each element separated by a
# space. After you have no more rows left, press enter with
+out
# typing anything when prompted for the next row. The only
+keys
# you should use are: enter, space, and the numbers. Happy
# matrix multiplying. :-)
#
# Copyright (C) 2000 Zenon Zabinski. No rights reserved.
#
use strict;
my (@firstfactor, @secondfactor, @product);
@firstfactor = getmatrix ("First");
@secondfactor = getmatrix ("Second");
@product = getproduct (\@firstfactor, \@secondfactor);
printmatrix (@product);
# SUBS:
sub getmatrix {
my @matrix;
print "\n". shift() ." matrix:\n";
while (<STDIN>) {
chop;
last if (!$_);
if (/[^0-9 ]/) { die "Not a legal matrix row!\n"; }
push @matrix, [ split / / ];
}
return @matrix;
}
sub checkmatrix {
my $rowlength = $#{$_[0]};
for (@_) {
$rowlength == $#$_ or die "Number of columns was not consistent!\n
+";
}
}
sub printmatrix {
foreach (@_) {
print "[ ";
printf("%-4s", " $_") foreach (@$_);
print " ]\n";
}
}
sub getdimen {
my $rows = @_;
my $cols = $#{$_[0]};
return ($rows - 1, $cols);
}
sub getproduct {
my ($a, $b) = @_;
my @product;
checkmatrix(@$a);
checkmatrix(@$b);
my ($arow, $acol) = getdimen(@$a);
my ($brow, $bcol) = getdimen(@$b);
$acol == $brow or die "The matrices can't be multiplied!\n";
for my $i (0..$arow) {
for my $j (0..$bcol) {
for my $k (0..$acol) {
$product[$i][$j] += $$a[$i][$k] * $$b[$k][$j];
}
}
}
return @product;
}
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