AI-PSO
view release on metacpan or search on metacpan
examples/NeuralNet/pso_ann.pl view on Meta::CPAN
my $numInputs = 3;
my $numHidden = 2;
my $xferFunc = "Logistic";
my $annConfig = "pso.ann";
my $annInputs = "pso.dat";
my $expectedValue = 3.5; # this is the value that we want to train the ANN to produce (just like the example in t/PTO.t)
sub test_fitness_function(@) {
my (@arr) = (@_);
&writeAnnConfig($annConfig, $numInputs, $numHidden, $xferFunc, @arr);
my $netValue = &runANN($annConfig, $annInputs);
print "network value = $netValue\n";
# the closer the network value gets to our desired value
# then we want to set the fitness closer to 1.
#
# This is a special case of the sigmoid, and looks an awful lot
# like the hyperbolic tangent ;)
examples/NeuralNet/pso_ann.pl view on Meta::CPAN
pso_set_params(\%test_params);
pso_register_fitness_function('test_fitness_function');
pso_optimize();
#my @solution = pso_get_solution_array();
##### io #########
sub writeAnnConfig() {
my ($configFile, $inputs, $hidden, $func, @weights) = (@_);
open(ANN, ">$configFile");
print ANN "$inputs $hidden\n";
print ANN "$func\n";
foreach my $weight (@weights) {
print ANN "$weight ";
}
print ANN "\n";
close(ANN);
}
sub runANN($$) {
my ($configFile, $dataFile) = @_;
my $networkValue = `ann_compute $configFile $dataFile`;
chomp($networkValue);
return $networkValue;
}
lib/AI/PSO.pm view on Meta::CPAN
my @solution = ();
#---------- END GLOBAL DATA STRUCTURES --------
#---------- BEGIN EXPORTED SUBROUTINES ----------
#
# pso_set_params
# - sets the global module parameters from the hash passed in
#
sub pso_set_params(%) {
my (%params) = %{$_[0]};
my $retval = 0;
#no strict 'refs';
#foreach my $key (keys(%params)) {
# $$key = $params{$key};
#}
#use strict 'refs';
$numParticles = defined($params{numParticles}) ? $params{numParticles} : 'null';
lib/AI/PSO.pm view on Meta::CPAN
$retval = 1 if($param_string =~ m/null/);
return $retval;
}
#
# pso_register_fitness_function
# - sets the user-defined callback fitness function
#
sub pso_register_fitness_function($) {
my ($func) = @_;
$user_fitness_function = new Callback(\&{"main::$func"});
return 0;
}
#
# pso_optimize
# - runs the particle swarm optimization algorithm
#
sub pso_optimize() {
&init();
return &swarm();
}
#
# pso_get_solution_array
# - returns the array of parameters corresponding to the best solution so far
sub pso_get_solution_array() {
return @solution;
}
#---------- END EXPORTED SUBROUTINES ----------
#--------- BEGIN INTERNAL SUBROUTINES -----------
#
# init
# - initializes global variables
# - initializes particle data structures
#
sub init() {
if($psoRandomRange =~ m/null/) {
$useModifiedAlgorithm = 1;
} else {
$useModifiedAlgorithm = 0;
}
&initialize_particles();
}
#
# initialize_particles
# - sets up internal data structures
# - initializes particle positions and velocities with an element of randomness
#
sub initialize_particles() {
for(my $p = 0; $p < $numParticles; $p++) {
$particles[$p] = {}; # each particle is a hash of arrays with the array sizes being the dimensionality of the problem space
$particles[$p]{nextPos} = []; # nextPos is the array of positions to move to on the next positional update
$particles[$p]{bestPos} = []; # bestPos is the position of that has yielded the best fitness for this particle (it gets updated when a better fitness is found)
$particles[$p]{currPos} = []; # currPos is the current position of this particle in the problem space
$particles[$p]{velocity} = []; # velocity ... come on ...
for(my $d = 0; $d < $dimensions; $d++) {
$particles[$p]{nextPos}[$d] = &random($deltaMin, $deltaMax);
$particles[$p]{currPos}[$d] = &random($deltaMin, $deltaMax);
lib/AI/PSO.pm view on Meta::CPAN
#
# initialize_neighbors
# NOTE: I made this a separate subroutine so that different topologies of neighbors can be created and used instead of this.
# NOTE: This subroutine is currently not used because we access neighbors by index to the particle array rather than storing their references
#
# - adds a neighbor array to the particle hash data structure
# - sets the neighbor based on the default neighbor hash function
#
sub initialize_neighbors() {
for(my $p = 0; $p < $numParticles; $p++) {
for(my $n = 0; $n < $numNeighbors; $n++) {
$particles[$p]{neighbor}[$n] = $particles[&get_index_of_neighbor($p, $n)];
}
}
}
sub dump_particle($) {
$| = 1;
my ($index) = @_;
print STDERR "[particle $index]\n";
print STDERR "\t[bestPos] ==> " . &compute_fitness(@{$particles[$index]{bestPos}}) . "\n";
foreach my $pos (@{$particles[$index]{bestPos}}) {
print STDERR "\t\t$pos\n";
}
print STDERR "\t[currPos] ==> " . &compute_fitness(@{$particles[$index]{currPos}}) . "\n";
foreach my $pos (@{$particles[$index]{currPos}}) {
print STDERR "\t\t$pos\n";
lib/AI/PSO.pm view on Meta::CPAN
print STDERR "\t[velocity]\n";
foreach my $pos (@{$particles[$index]{velocity}}) {
print STDERR "\t\t$pos\n";
}
}
#
# swarm
# - runs the particle swarm algorithm
#
sub swarm() {
for(my $iter = 0; $iter < $maxIterations; $iter++) {
for(my $p = 0; $p < $numParticles; $p++) {
## update position
for(my $d = 0; $d < $dimensions; $d++) {
$particles[$p]{currPos}[$d] = $particles[$p]{nextPos}[$d];
}
## test _current_ fitness of position
my $fitness = &compute_fitness(@{$particles[$p]{currPos}});
lib/AI/PSO.pm view on Meta::CPAN
}
&save_solution(@{$particles[$bestPartIndex]{bestPos}});
&dump_particle($bestPartIndex);
return 1;
}
#
# save solution
# - simply copies the given array into the global solution array
#
sub save_solution(@) {
@solution = @_;
}
#
# compute_fitness
# - computes the fitness of a particle by using the user-specified fitness function
#
# NOTE: I originally had a 'fitness cache' so that particles that stumbled upon the same
# position wouldn't have to recalculate their fitness (which is often expensive).
# However, this may be undesirable behavior for the user (if you come across the same position
# then you may be settling in on a local maxima so you might want to randomize things and
# keep searching. For this reason, I'm leaving the cache out. It would be trivial
# 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;
# }
lib/AI/PSO.pm view on Meta::CPAN
$return_fitness = $user_fitness_function->call(@values);
return $return_fitness;
}
#
# random
# - returns a random number that is between the first and second arguments using the Math::Random module
#
sub random($$) {
my ($min, $max) = @_;
return random_uniform(1, $min, $max)
}
#
# get_index_of_neighbor
#
# - returns the index of Nth neighbor of the index for particle P
# ==> A neighbor is one of the next K particles following P where K is the neighborhood size.
# So, particle 1 has neighbors 2, 3, 4, 5 if K = 4. particle 4 has neighbors 5, 6, 7, 8
# ...
#
sub get_index_of_neighbor($$) {
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) {
$dx = $deltaMin;
} elsif($dx > $deltaMax) {
$dx = $deltaMax;
}
return $dx;
}
#--------- END INTERNAL SUBROUTINES -----------
themMax => 1.0,
exitFitness => 0.99,
verbose => 1,
);
my %test_params2 = %test_params;
$test_params2{psoRandomRange} = 4.0;
# simple test function to sum the position values up to 3.5
my $testValue = 3.5;
sub test_fitness_function(@) {
my (@arr) = (@_);
my $sum = 0;
my $ret = 0;
foreach my $val (@arr) {
$sum += $val;
}
# sigmoid-like ==> squash the result to [0,1] and get as close to 3.5 as we can
return 2 / (1 + exp(abs($testValue - $sum)));
return $ret;
( run in 0.744 second using v1.01-cache-2.11-cpan-3b35f9de6a3 )