#!/usr/bin/perl
#		ignore commented (#) and empty lines,
#		and compute square difference of columns 2,3,..
#		provided that data in column 1 are the same (otherwise ignore)
#		version 1.0 - by Nicola Manini - Jan 2003


if($#ARGV == 1)
{
    $InputFile1=shift(@ARGV);
    $InputFile2=shift(@ARGV);

    open(I1, $InputFile1);
    open(I2, $InputFile2);

    while ($line1 = <I1>){
	if($line1 !~/^\#/ && $line1 !~/^\s*$/){
#	    print "QUII 1:  ".$line1;
	    $nl1++;
	    while ($line2 = <I2>){
		if($line2 !~/^\#/ && $line2 !~/^\s*$/){
#		    print "QUII 2:  ".$line2;
		    $nl2++;
		    @li1=split(/\s+/,$line1);@li2=split(/\s+/,$line2);
		    if($li1[0]==$li2[0]){
			$nlp++;
			printf "%21.16g",shift(@li1);
			shift(@li2);
			while($#li1>=0 && $#li2>=0){
			    printf " %21.16g",(shift(@li1) - shift(@li2))**2;
			}
			print "\n";
		    }
		    last;	# jump out of the <I2> loop and get next $line1
		}
	    }
	}
    }
    close(I1);close(I2);
#    print "QUAA ".$nl1." ".$nl2."\n";
    if($nl1 != $nl2){print STDERR "squarediff warning: \# lines in ".$InputFile1." and ".$InputFile2. " do not match\n";}
    elsif($nlp == 0 ){print STDERR "squarediff warning: no lines matching\n";}
    elsif($nlp/$nl1<0.01 || $nl1/$nl2<0.01){print STDERR "squarediff warning:  very few lines in output\n";}
}
else
{
    print STDERR "usage: squarediff file1 file2  [file1/2 can be - for stdin]\n";
}