in reply to Quantum::Superpositions prob

tommycahir,
I think you were just banking on something that Quantum::Superpositions doesn't promise. The eigenstates function returns a list of states in the superposition, but does not say in order. I peeked under the hood and discovered that it generates a unique list by using a hash and we all know that hash order is not array order. There are ways to still use the module and maintain order - but it requires more work.

Hope this helps - L~R

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Re: Re: Quantum::Superpositions prob
by tommycahir (Acolyte) on Mar 25, 2004 at 15:10 UTC
    how would i go about this, is there much work involved.
    What i really am aiming to do is
    1.to have an array of routers visited and an array of routers to_visit,
    2.then then remove the routers visited from the to_visit array
    3.continue to visit each one of these routers in turn finding out what other routers they connected to and adding them to the to_visit array
    4.repeat from step 2 till no more left in the to_visit array.
[reply]
      tommychahir,
      Of course this can be done without Quantum::Superpositions, but since this sounded like fun: 
      #! /usr/bin/perl
use strict;
use warnings;
use Quantum::Superpositions;

my @array_1 = (1 .. 4);
my @array_2 = qw{1 2 2 3 3 3 4 4 4 4 5 6 7};

my @array_3 = eigenstates( any(@array_2) != all(@array_1) );
my @array_4 = Quantum::Superpositions::eigenstates( any(@array_2) != a
+ll(@array_1) );

print "Ordered:\n";
print "$_\n" for @array_3;
print "Hash:\n";
print "$_\n" for @array_4;

{
    no warnings 'redefine';
    *eigenstates = *main::eigenstates;
    sub eigenstates ($) {
        my @uniq;
        my %seen;
        for ( Quantum::Superpositions::collapse( $_[0] ) ) {
            push @uniq , $_ if ! $seen{$_};
            $seen{$_}++;
        }
        return @uniq;
    }
}

      [download]
      Cheers - L~R
[reply]
[d/l]
      tommycahir,
      Ok, since I have already provided a way to do it using Quantum::Superpositions, I should point out that there certainly are simpler solutions. Since your goal is just to visit all routers, order really should not matter: 
      my @visited   = (1 .. 5);
my %unvisited = map { $_ => undef } 1 .. 9;

while ( %unvisited ) {
    delete @{unvisited}{@visited};
    for ( keys %unvisited ) {
        visit( $_, \%unvisited );    # Adds routers to %unvisited
        push @visited , $_;
    }
}

      [download]
      Now if for some reason order is important to you, you can reverse the array/hash for the stack. 
      my %visited   = map { $_ => undef } (1 .. 4);
my @unvisited = (1 .. 9);

while ( @unvisited ) {
    my $router = shift @unvisited;
    next if exists $visited{$router};
    visit ( $router, \@unvisited );   # Adds routers to @unvisited
    $visited{$router} = undef;
}

      [download]
      I hope these solutions are helpful.

      Cheers - L~R

[reply]
[d/l]
[select]
        L~R
        tanx for all the help i think i have it going now. order is important as i want to see what router is connected to what.
        the code i actually used was very similar to what u just given..
        once again your fountain of knowledge amazes me
        thanking you
        tommy
[reply]

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