Hi, I tried to run your first piece of code to better visualize the data, but even that part does not work properly and probably never ends. These nested loops don't work: 
for(my $i=1; $i<=$x; ++$i){
        for(my $j=0; $j<$y; ++$j){
                for(my $k=0; $k<$y; ++$j){                       
                        $distance_mat -> [$i][$j][$k] = rand 1;
                }   
        }   
}

[download]
because the third line increments $j and tests max value on $k, so that will probably never ends. A minimum correction on the first part would be: 
use strict;
use warnings;
use Data::Dumper;

my $x = 4;
my $y = 5;
my $distance_mat;
####################
for(my $i=1; $i<=$x; ++$i){
        for(my $j=0; $j<$y; ++$j){
                for(my $k=0; $k<$y; ++$k){                       
                        $distance_mat -> [$i][$j][$k] = rand 1;
                }   
        }   
}
##############Start and end nodes have zero cost
for(my $i=0; $i<scalar(@{$distance_mat->[1]}); ++$i){
        $distance_mat -> [0][0][$i] = 0;
}
for(my $i=0; $i<scalar(@{$distance_mat->[-1]}); ++$i){
        $distance_mat -> [-1][0][$i] = 0;
}

print Dumper $distance_mat;

[download]
which will print out: 
$VAR1 = [
          [
            [
              0,
              0,
              0,
              0,
              0
            ]
          ],
          [
            [
              '0.212283829766424',
              '0.693160487196536',
              '0.721569572380883',
              '0.0147371758675447',
              '0.508071977540641'
            ],
            [
              '0.607456981189884',
              '0.413801502805963',
              '0.962572895729942',
              '0.938935399978082',
              '0.717291943322152'
            ],
            [
              '0.306279826459825',
              '0.89992134970587',
              '0.690479726793445',
              '0.733121785882545',
              '0.487829205187605'
            ],
            [
              '0.711943004833408',
              '0.254652102915149',
              '0.267465127747556',
              '0.302759025077147',
              '0.32486696921206'
            ],
            [
              '0.489091147270205',
              '0.0735180399392874',
              '0.235300433159548',
              '0.746479779929494',
              '0.905501634741288'
            ]
          ],
          [
            [
              '0.688008245370213',
              '0.113680627990203',
              '0.99717709784958',
              '0.510060769658413',
              '0.767946103966395'
            ],
            [
              '0.947138589977666',
              '0.369698435985974',
              '0.651511387205236',
              '0.211410103277188',
              '0.21735370417333'
            ],
            [
              '0.734569009367142',
              '0.598363562918809',
              '0.431561123751734',
              '0.712531952111899',
              '0.293976071886583'
            ],
            [
              '0.517267742541694',
              '0.55231451959105',
              '0.45234384270081',
              '0.147473762126175',
              '0.290022437346682'
            ],
            [
              '0.470738612969299',
              '0.0427293275962448',
              '0.777329578040955',
              '0.144845576196932',
              '0.608144103958836'
            ]
          ],
          [
            [
              '0.012097916474044',
              '0.488911202200264',
              '0.424603577528178',
              '0.187457713190881',
              '0.608602384605799'
            ],
            [
              '0.492303567493103',
              '0.334913914644719',
              '0.232936661637211',
              '0.929022161683616',
              '0.616006850324688'
            ],
            [
              '0.150798208707261',
              '0.409304914407997',
              '0.553553019401473',
              '0.173385566856545',
              '0.882371508058217'
            ],
            [
              '0.786329035626949',
              '0.480783348396823',
              '0.719431190274186',
              '0.656542212578945',
              '0.632677581767197'
            ],
            [
              '0.699789445283013',
              '0.941904765904233',
              '0.239623890103449',
              '0.176224763809842',
              '0.261173130161335'
            ]
          ],
          [
            [
              0,
              0,
              0,
              0,
              0
            ],
            [
              '0.373621309619981',
              '0.411533490541188',
              '0.623695973015582',
              '0.00773593933377725',
              '0.00893442880364503'
            ],
            [
              '0.837186783303693',
              '0.584918955098058',
              '0.0295591991893147',
              '0.422034731454435',
              '0.260471634650969'
            ],
            [
              '0.82811137679651',
              '0.49858938564811',
              '0.153148378721244',
              '0.500505552716803',
              '0.679154015831099'
            ],
            [
              '0.0258503603085316',
              '0.399454916212452',
              '0.470265378306834',
              '0.498481414135323',
              '0.832463141199078'
            ]
          ]
        ];

[download]
Notice how Data::Dumper makes it possible to visualize your data structure. Looking at the above structure, it would seem (but I cannot be sure) that you would probably want to use the post increment operators, rather than the pre increment operator. Or, better, use the 
for my $i (0..$max_val)

[download]
syntax. Please fix this part of your code so that we can understand what you are trying to do and agree on your input, then only can we think really on the rest of your program. And, at this point, you probably want to open a new thread (referring to this one) with the input part properly fixed, son that we can then focus on the rest.

In reply to Re: Viterbi application by Laurent_R
in thread Viterbi application by azheid

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