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####
# SimulatedAnnealing.pm:  A Perl module that exports a single public
# function, anneal(), for optimizing a list of numbers according to a
# specified cost function.
#
####
#
# Copyright 2010 by Benjamin Fitch.
#
# This library is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.
####
package AI::SimulatedAnnealing;

use 5.010001;
use strict;
use warnings;
use utf8;

use English "-no_match_vars";
use Hash::Util ("lock_keys");
use List::Util ("first", "max", "min", "sum");
use POSIX ("ceil", "floor");
use Scalar::Util ("looks_like_number");

use Exporter;

# Version:
our $VERSION = '1.02';

# Specify default exports:
our @ISA = ("Exporter");
our @EXPORT = (
  "anneal",
  );

# Constants:
my $POUND     = "#";
my $SQ        = "'";
my $DQ        = "\"";
my $SEMICOLON = ";";
my $CR        = "\r";
my $LF        = "\n";
my $SPACE     = " ";
my $EMPTY     = "";
my $TRUE      = 1;
my $FALSE     = 0;

my $TEMPERATURE_MULTIPLIER = 0.95;

# The anneal() function takes a reference to an array of number
# specifications (which are references to hashes containing "LowerBound",
# "UpperBound", and "Precision" fields), a reference to a cost function
# (which takes a list of numbers matching the specifications and returns a
# number representing a cost to be minimized), and a positive integer
# specifying the number of randomization cycles to perform at each
# temperature during the annealing process.
#
# The function returns a reference to an array containing the
# optimized list of numbers.
sub anneal {
    my $number_specs = validate_number_specs($_[0]);
    my $cost_function = $_[1];
    my $cycles_per_temperature = $_[2];

    my $current_temperature;
    my $lowest_cost;

    my @integral_lower_bounds;
    my @integral_upper_bounds;
    my @optimized_list;

    $current_temperature = 1;

    for my $number_spec (@{ $number_specs }) {
        push @integral_lower_bounds, int($number_spec->{"LowerBound"}
          * (10 ** $number_spec->{"Precision"}));
        push @integral_upper_bounds, int($number_spec->{"UpperBound"}