@nucleotides=('A','T','G','C');
foreach(1..1000)
	{
	$seq1.=$nucleotides[int(rand(3))];
	}
foreach(1..1000)
	{
	$seq2.=$nucleotides[int(rand(3))];
	}

##</code><code>##

my @nucleotides = qw( A T G C );
foreach ( 1 .. 1_000 )
	{
	$seq1 .= $nucleotides[ rand @nucleotides ];
	$seq2 .= $nucleotides[ rand @nucleotides ];
	}

##</code><code>##

@seq1=split('',$seq1);
foreach(1..$window_size)
	{
	shift@seq1;
	}
@seq2=split('',$seq2);
foreach(1..$window_size)
	{
	shift@seq2;
	}

##</code><code>##

my @seq1 = split //, $seq1;
splice @seq1, 0, $window_size;
my @seq2 = split //, $seq2;
splice @seq2, 0, $window_size;

##</code><code>##

open(OUT,">ID_matrix.txt");

##</code><code>##

open OUT, '>', 'ID_matrix.txt' or die "Cannot open 'ID_matrix.txt' because: $!";