[英]Python DEAP and multiprocessing on Windows: AttributeError
我有以下情况:
有一个 main.py
def main():
...
schedule.schedule()
...
if __name__== "__main__":
main()
然后,我还有一个文件 schedule.py
def schedule()
...
toolbox = base.Toolbox()
creator.create("FitnessMin", base.Fitness, weights=(-1.0,))
creator.create("Individual", list, fitness=creator.FitnessMin)
toolbox.register('individual', init_indiv, creator.Individual, bounds=bounds)
toolbox.register("population", tools.initRepeat, list, toolbox.individual)
toolbox.register("evaluate", fitness, data=args)
toolbox.register("mate", tools.cxTwoPoint)
toolbox.register("mutate", tools.mutFlipBit, indpb=0.05)
toolbox.register("select", tools.selTournament, tournsize=3)
# Further parameters
cxpb = 0.7
mutpb = 0.2
# Measure how long it takes to caluclate 1 generation
MAX_HOURS_GA = parameter._MAX_HOURS_GA
POPSIZE_GA = parameter._POPSIZE_GA
pool = multiprocessing.Pool(processes=4)
toolbox.register("map", pool.map)
pop = toolbox.population(n=POPSIZE_GA * len(bounds))
result = algorithms.eaSimple(pop, toolbox, cxpb, mutpb, 1, verbose=False)
现在,执行它会给我以下错误:
Process SpawnPoolWorker-1:
Traceback (most recent call last):
File "C:\Users\...\lib\multiprocessing\process.py", line 297, in _bootstrap
self.run()
File "C:\Users\...\lib\multiprocessing\process.py", line 99, in run
self._target(*self._args, **self._kwargs)
File "C:\Users\...\lib\multiprocessing\pool.py", line 110, in worker
task = get()
File "C:\Users\...\lib\multiprocessing\queues.py", line 354, in get
return _ForkingPickler.loads(res)
AttributeError: Can't get attribute 'Individual' on <module 'deap.creator' from 'C:\\Users...
现在,我确实注意到 DEAP 文档( https://deap.readthedocs.io/en/master/tutorials/basic/part4.html )说
警告 如多处理指南中所述,在 Windows 下,由于进程的初始化方式,必须在 >if __name__ == "__main__" 部分中保护进程池。
但这并没有真正帮助我,因为我当然不想在我的 main 中拥有所有toolbox.register(...)
,甚至可能无法这样做。 只是移动池的创建
pool = multiprocessing.Pool(processes=4)
toolbox.register("map", pool.map)
对主要没有帮助。
似乎还有其他人有类似的问题,甚至最近( https://github.com/rsteca/sklearn-deap/issues/59 )。 对于他们中的大多数人来说,似乎存在某种解决方法,但它们似乎都不适合我的情况,或者至少我不知道如何让它们工作。 我也尝试过按照注册函数和初始化池的顺序移动,但没有运气。 我也尝试过使用 SCOOP,但结果相似。
有任何想法吗?
解决方法是在全局scope中创建“FitnessMin”和“Individual”,即在main.py中:
import ...
creator.create("FitnessMin", base.Fitness, weights=(-1.0,))
creator.create("Individual", list, fitness=creator.FitnessMin)
def main():
...
schedule.schedule()
...
if __name__== "__main__":
main()
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