print PLP_FILE   "$aa_pos\t".$split_query_for_PLP[$s]."\t".$hash_plp_lbl_barrel_region_only{$s}."\n";

##</code><code>##

for (my $s = $start_of_barrel_region; $s <= (($start_of_barrel_region + $length_of_barrel_region)); $s++)
{
    my $aa_pos = $s + 1;
    warn "\$aa_pos is undefined when \$s is $s"               unless defined $aa_pos;
    warn "\$split_query_for_PLP[$s] is undefined"             unless defined $split_query_for_PLP[$s];
    warn "\$hash_plp_lbl_barrel_region_only{$s} is undefined" unless defined $hash_plp_lbl_barrel_region_only{$s};
    print PLP_FILE "$aa_pos\t".$split_query_for_PLP[$s] . "\t" . $hash_plp_lbl_barrel_region_only{$s} . "\n";    
}