This piece of code may do something similar what you need. 
use strict;
use warnings;
use diagnostics;

sub distance {
    my ($aa, $bb) = @_;
    return sqrt(($aa->[0] - $bb->[0])**2 +
                ($aa->[1] - $bb->[1])**2 +
                ($aa->[2] - $bb->[2])**2);
}

my $source = "./CONTCAR";

open(IN, '<', $source) or die "Couldn't open $source: $!\n";

my @data = map [ split ], grep /\S/, <IN>;

foreach my $d1 (@data) {
    foreach my $d2 (@data) {
        printf "($d1->[0],$d1->[1],$d1->[2]) <-> ($d2->[0],$d2->[1],$d
+2->[2]) = %f\n", distance($d1, $d2);
    }
}

close IN;

print "Done.\n";

[download]

In reply to Re^3: Subroutine not correct (I think) by pme
in thread Subroutine not correct (I think) by jcklasseter

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.