multiprocessing_mapreduce.py 文件源码

def __init__(self, map_func, reduce_func, num_workers=None):
        """
        map_func

          Function to map inputs to intermediate data. Takes as
          argument one input value and returns a tuple with the
          key and a value to be reduced.

        reduce_func

          Function to reduce partitioned version of intermediate
          data to final output. Takes as argument a key as
          produced by map_func and a sequence of the values
          associated with that key.

        num_workers

          The number of workers to create in the pool. Defaults
          to the number of CPUs available on the current host.
        """
        self.map_func = map_func
        self.reduce_func = reduce_func
        self.pool = multiprocessing.Pool(num_workers)