Deap: 粒子群优化算法

Source Code

#!usr/bin/env python
#-*- coding:utf-8 _*-
"""
@author:fonttian 
@file: Particle Swarm Optimization Basics.py 
@time: 2017/10/15 
"""
# ----------------------Modules----------------------
import operator
import random

import numpy

from deap import base
from deap import benchmarks
from deap import creator
from deap import tools

# ----------------------Representation----------------------
# 最大化粒子
# smin,smax 速度极限
creator.create("FitnessMax", base.Fitness, weights=(1.0,))
creator.create("Particle", list, fitness=creator.FitnessMax, speed=list,
    smin=None, smax=None, best=None)

# ----------------------Operators----------------------
# 初始化一个随机的位置,一个随机的速度
def generate(size, pmin, pmax, smin, smax):
    part = creator.Particle(random.uniform(pmin, pmax) for _ in range(size))
    part.speed = [random.uniform(smin, smax) for _ in range(size)]
    part.smin = smin
    part.smax = smax
    return part

# 首先计算速度,然后限制速度,最后计算粒子位置
def updateParticle(part, best, phi1, phi2):
    u1 = (random.uniform(0, phi1) for _ in range(len(part)))
    u2 = (random.uniform(0, phi2) for _ in range(len(part)))
    v_u1 = map(operator.mul, u1, map(operator.sub, part.best, part))
    v_u2 = map(operator.mul, u2, map(operator.sub, best, part))
    part.speed = list(map(operator.add, part.speed, map(operator.add, v_u1, v_u2)))
    for i, speed in enumerate(part.speed):
        if speed < part.smin:
            part.speed[i] = part.smin
        elif speed > part.smax:
            part.speed[i] = part.smax
    part[:] = list(map(operator.add, part, part.speed))

# The operators are registered in the toolbox with their parameters.
# The particle value at the beginning are in the range [-100, 100] (pmin and pmax),
# and the speed is limited in the range [-50, 50] through all the evolution.

# The evaluation function h1() is from [Knoek2003].
# The function is already defined in the benchmarks module, so we can register it directly.

# def evaluate(individual):
#     return sum(individual),

# size 种群大小
# pmin,pmax 初始值范围
# smin,smax 速度范围
toolbox = base.Toolbox()
toolbox.register("particle", generate, size=2, pmin=-6, pmax=6, smin=-3, smax=3)
toolbox.register("population", tools.initRepeat, list, toolbox.particle)
toolbox.register("update", updateParticle, phi1=2.0, phi2=2.0)
toolbox.register("evaluate", benchmarks.h1)
# toolbox.register("evaluate", evaluate)

# ----------------------Algorithm----------------------

def main():
    pop = toolbox.population(n=5)
    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)

    logbook = tools.Logbook()
    logbook.header = ["gen", "evals"] + stats.fields

    GEN = 1000
    best = None

    for g in range(GEN):
        for part in pop:
            print(part)
            part.fitness.values = toolbox.evaluate(part)
            if not part.best or part.best.fitness < part.fitness:
                part.best = creator.Particle(part)
                part.best.fitness.values = part.fitness.values
            if not best or best.fitness < part.fitness:
                best = creator.Particle(part)
                best.fitness.values = part.fitness.values
        for part in pop:
            toolbox.update(part, best)

        # Gather all the fitnesses in one list and print the stats
        logbook.record(gen=g, evals=len(pop), **stats.compile(pop))
        print(logbook.stream)

    return pop, logbook, best

if __name__ == "__main__":
    pop, logbook, best = main()
    print("最终族群 :",pop) # 没什么用
    # print("统计数据 :",logbook)
    print("最佳种群 :",best)
    print("最佳种群的适应度 :",benchmarks.h1(best))
    # print("最佳个体的适应度 :",evaluate(best))

Output(默认执行时会输出统计数据)