Hi all. This isn't a very well known module, nor well documented (In my google-ing experience). Any ideas would be appreciated. This is my script: 
#!/usr/bin/perl
use strict;
use warnings;
use Math::Vector::Real;
use constant DEG_PER_RAD => 45 / atan2(1, 1);

my ( $source, $out ) = qw/ IN OUT /;

open my $in_fh,  '<', $source or die qq{Unable to open "$source" for i
+nput: $!\n};
open my $out_fh, '>', $out    or die qq{Unable to open "$out" for outp
+ut: $!\n};
#select $out_fh;

my @data;

push @data, V(split) while <$in_fh>;

for my $i ( 0 .. $#data-1 ) {
    for my $j ( $i+1 .. $#data ) {
        my $val1 = $data[$i];
        my $val2 = $data[$j];
        my $comp1 = $val1->[0];
        my $comp2 = $val2->[0];
        my $vect1 = $val1->[3..5];
        my $vect2 = $val2->[3..5];
        my $norm = $val1->[0..2];
        my $nvect1 = $vect1 - $norm ;
        my $nvect2 = $vect1 - $norm ;
                if( $comp1 != $comp2 ){
                         next;}else{
                    my $degrees = atan2($nvect1, $nvect2) * DEG_PER_RA
+D;
                    print "$degrees\n";
                }
       }
}

[download]
In essence, the script reads the input and assigns each line to a vector via the Math::Vector::Real module. My input file is like so: 
 
2 2 2 5 -2 1
2 2 2 2 7 4
5 2 2 2 7 4

[download]
Which are location coordinates. The first 3 numbers on each line correspond to a point, and the other 3 in the line correspond to a nearby point. The first set will often be identical from line to line. The second set will never repeat between consecutive lines like the first. I'm trying to find the angle between the second set of coordinates between two separate rows, after normalizing them with respect to the first set of coordinates. The script works (via print testing) up until  my $vect1 = $val1->[3..5];. When I print test here, I get:  2 (And a whole host of other errors that stem from this) I cannot find out how to split the values of a vector off into a new vector like I'm trying to. Does anyone have any ideas? Thanks.

In reply to Vector manipulation by jcklasseter

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