examples/ga/onemax_mp.py

#!/usr/bin/env python2.7
#    This file is part of DEAP.
#
#    DEAP is free software: you can redistribute it and/or modify
#    it under the terms of the GNU Lesser General Public License as
#    published by the Free Software Foundation, either version 3 of
#    the License, or (at your option) any later version.
#
#    DEAP is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#    GNU Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with DEAP. If not, see <http://www.gnu.org/licenses/>.

import array
import multiprocessing
import random
import sys

if sys.version_info < (2, 7):
    print("mpga_onemax example requires Python >= 2.7.")
    exit(1)

import numpy

from deap import algorithms
from deap import base
from deap import creator
from deap import tools

def evalOneMax(individual):
    return sum(individual),

def main(seed):
    random.seed(seed)

    creator.create("FitnessMax", base.Fitness, weights=(1.0,))
    creator.create("Individual", array.array, typecode='b', fitness=creator.FitnessMax)

    toolbox = base.Toolbox()

    # Attribute generator
    toolbox.register("attr_bool", random.randint, 0, 1)

    # Structure initializers
    toolbox.register("individual", tools.initRepeat, creator.Individual, toolbox.attr_bool, 100)
    toolbox.register("population", tools.initRepeat, list, toolbox.individual)

    toolbox.register("evaluate", evalOneMax)
    toolbox.register("mate", tools.cxTwoPoint)
    toolbox.register("mutate", tools.mutFlipBit, indpb=0.05)
    toolbox.register("select", tools.selTournament, tournsize=3)

    # Process Pool of 4 workers
    pool = multiprocessing.Pool(processes=4)
    toolbox.register("map", pool.map)

    pop = toolbox.population(n=300)
    hof = tools.HallOfFame(1)
    stats = tools.Statistics(lambda ind: ind.fitness.values)
    stats.register("avg", numpy.mean)
    stats.register("std", numpy.std)
    stats.register("min", numpy.min)
    stats.register("max", numpy.max)

    algorithms.eaSimple(pop, toolbox, cxpb=0.5, mutpb=0.2, ngen=40,
                        stats=stats, halloffame=hof)

    pool.close()

if __name__ == "__main__":
    main(64)