one argument process

Notice that args should be itrable. like index. But we can use a little trick to tackle none iterable ones.

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def func(resolver):
    return resolver.getFormatedVocaloidDataInDict()

We put a “,” after none iterable args.

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results = [pool.apply_async(func, args=(resolverX,)) for resolverX in [resolver for i in range(num_cores)]]

template

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# import datetime
import multiprocessing as mp

# # initialise the pool
num_cores = int(mp.cpu_count())
# print("本地计算机有: " + str(num_cores) + " 核心")
pool = mp.Pool(num_cores)

# # preparation processes
processes = [pool.apply_async(func0, args=(arg0,)) for arg0 in argList]
processes.append(pool.apply_async(func1, args=(argX,)))

# start_t = datetime.datetime.now()
results = [p.get() for p in processes]
# end_t = datetime.datetime.now()

# elapsed_sec = (end_t - start_t).total_seconds()
# print("多进程计算 共消耗: " + "{:.2f}".format(elapsed_sec) + " 秒")
  1. func0 and func1 can be lambda func.
  2. prepare processes not starting any processes, so cost are really small.
  3. if func has return we use .get(), or .start() is enough

example

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import math
import datetime
import multiprocessing as mp


def func(name, resolver):
    return{name: resolver.getFormatedVocaloidDataInDict()}


if __name__ == '__main__':

    start_t = datetime.datetime.now()

    num_cores = int(mp.cpu_count())
    print("本地计算机有: " + str(num_cores) + " 核心")

    pool = mp.Pool(num_cores)

    results = [pool.apply_async(func, args=(name,resolverX)) for name, resolverX in [(i, resolver) for i in range(num_cores)]]
    
    results = [p.get() for p in results]

    end_t = datetime.datetime.now()
    elapsed_sec = (end_t - start_t).total_seconds()
    print("多进程计算 共消耗: " + "{:.2f}".format(elapsed_sec) + " 秒")

questions

jupyter notebook not support multiprocessing package -> try multiprocess instead of multiprocessing https://stackoverflow.com/questions/48846085/python-multiprocessing-within-jupyter-notebook

progress bar -> https://www.jianshu.com/p/1d6e0d07eb4a

gpu acceleration -> https://www.cnblogs.com/noluye/p/11517489.html