my @distance_mat=[];
...
my @vit_dist=[ [ 0] ];

##</code><code>##

${$vit_dist[$i]}[$j]=min(${$vit_dist[$i-1]}[$j]+${$distance_mat[$i]}[$j];

##</code><code>##

${${$distance_mat[$i]}[$j]}[$k]

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

my $max_index = 1;
my $matrix;

for my $i (0 .. $max_index) {
    for my $j (0 .. $max_index) {
        for my $k (0 .. $max_index) {
            $matrix->[$i][$j][$k] = rand 1;
        }
    }
}

use Data::Dump;
dd $matrix;

##</code><code>##

[
  [
    [0.290579816865833, 0.491432556740136],
    [0.888187692306143, 0.761365009561764],
  ],
  [
    [0.865674078359991, 0.284696276285089],
    [0.0562126863718184, 0.781856824452085],
  ],
]