open(IN,  " < $infile" );

    my $si=8192;  # the number of entries is known

    my %matrix;

    while(my $c<$si) {

        read(IN, my $bin, 4);
        $data = unpack('N', $bin);		  
		    
        my $d = Unshuffle($c);
		  
        $matrix{$d} += $data;
		    
        $c++;
    }

    close( IN );

    open(OUT, " >$outfile" );

    foreach my $d (sort {$a <=> $b} (keys %matrix)) {
        print (OUT pack('V', $matrix{$d}));
    }

    close( OUT );