A convenient method I use to save an arbitrary structure of data to a textfile is to use our famous Data::Dumper core module to capture the variable's content in a string.
When I need it again I just use an eval to convert the string back into my matrix or other datastructure.

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

my @data = (0,1,2,3 );
print "BEFORE: ",join(',',@data),"\n";
my $saved_data = Dumper(\@data);
# ...here you would write saved data to textfile
my $VAR1; eval $saved_data;
my @data2 = @{$VAR1};
print "AFTER: ",join(',',@data2),"\n";
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Output would be:

BEFORE: 0,1,2,3
AFTER: 0,1,2,3
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