use strict;

#-- Define in/out files
my $inf = "test.txt" ;

#-- variables and handles 
my $line; my $a; my $b; my @result;

@row = ((0) x 361);
@column = ((0) x 361);
my @Matrix = ( @row, @column);

#--Open the input and output files
open (IN,  "$inf") || die "Can't read $inf";

while ($line = <IN>)
{
 @result   = split(/\s+/, $line);
 $a = $result[0]; 
 $a = int($phi);
 $b = $result[1];
 $b = int($psi);

@Matrix[$row[($a+180)]][$column[($b+180)]] += 1;
   
}
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Actually, your code has a number of problems.
• that isn't how you initialize a 2-dimensional array. your initialization of @matrix will make a 722 element 1d array. You would need something like: @matrix=map {[(0) x 361]} (0..361);
• From what I can see you want:  $Matrix[$a+180][$b+180] += 1;

I would suggest giving Modern Perl or Learning Perl and Programming Perl a good read to get down some of the fundamentals.

Update: Also you set $a and $b to values, then immediately set them to int($phi) and int($psi) which are undefined. If you were running with strict and warnings the compiler would have shown you that.



-pete
"Worry is like a rocking chair. It gives you something to do, but it doesn't get you anywhere."

Many thanks for your advice :) I will try my best

@Matrix[$row($a+180)][$column($b+180)] += 1;

should be something like

$Matrix[$row($a+180)][$column($b+180)] += 1;

He definitely wants $row[$a+180] rather than $row($a+180) in the matrix operation, but I really think he wants just $a+180, since he never fills @row and @column with anything other than 0.


-pete
"Worry is like a rocking chair. It gives you something to do, but it doesn't get you anywhere."

Yes ofcourse, sorry I missed that :s Many thanks for your help :)