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lib/AI/PSO.pm  view on Meta::CPAN

#       for users to implement their own cache since they are passed the same array of values.
#
sub compute_fitness(@) {
    my (@values) = @_;
    my $return_fitness = 0;

#    no strict 'refs';
#    if(defined(&{"main::$user_fitness_function"})) {
#        $return_fitness = &$user_fitness_function(@values);
#    } else {
#        warn "error running user_fitness_function\n";
#        exit 1;
#    }
#    use strict 'refs';

    $return_fitness = $user_fitness_function->call(@values);

    return $return_fitness;
}

lib/AI/PSO.pm  view on Meta::CPAN

#
# get_index_of_neighbor
#
# - returns the index of Nth neighbor of the index for particle P
# ==> A neighbor is one of the next K particles following P where K is the neighborhood size.
#    So, particle 1 has neighbors 2, 3, 4, 5 if K = 4.  particle 4 has neighbors 5, 6, 7, 8
#    ...
# 
sub get_index_of_neighbor($$) {
    my ($particleIndex, $neighborNum) = @_;
    # TODO: insert error checking code / defensive programming
    return ($particleIndex + $neighborNum) % $numParticles;
}


#
# get_index_of_best_fit_neighbor
# - returns the index of the neighbor with the best fitness (when given a particle index)...
# 
sub get_index_of_best_fit_neighbor($) {
    my ($particleIndex) = @_;
    my $bestNeighborFitness   = 0;
    my $bestNeighborIndex     = 0;
    my $particleNeighborIndex = 0;
    for(my $neighbor = 0; $neighbor < $numNeighbors; $neighbor++) {
        $particleNeighborIndex = &get_index_of_neighbor($particleIndex, $neighbor);
        if(&compute_fitness(@{$particles[$particleNeighborIndex]{bestPos}}) > $bestNeighborFitness) { 
            $bestNeighborFitness = &compute_fitness(@{$particles[$particleNeighborIndex]{bestPos}});
            $bestNeighborIndex = $particleNeighborIndex;
        }
    }
    # TODO: insert error checking code / defensive programming
    return $particleNeighborIndex;
}

#
# clamp_velocity
# - restricts the change in velocity to be within a certain range (prevents large jumps in problem hyperspace)
#
sub clamp_velocity($) {
    my ($dx) = @_;
    if($dx < $deltaMin) {