Hi

I would like to notify some points to you, from your code.

 unless (open(INPUT, "$inputfile"))
    {
    print "ERROR: Can't open file for reading : $!\n";

    }
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If there is any error in opening the file Just you are printing the error message and continuing the code with
while ( <INPUT> ).

How can you do that ?
Is that mandatory in your code? Just think it off on that.

# splitting on tab character

    my @data = split("\t", $_);

    # assigning varables

    my $did1 = $data[0];
    my $did2 = $data[1];
    my $score1 = $data[2];
    my $score2 = $data[3];
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The above code can be written as

my ( $did1,$did2,$score1,$score2 ) = (split("\t", $_))[0..3];
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