Source code for toasty.par_util

# -*- mode: python; coding: utf-8 -*-
# Copyright 2020 the AAS WorldWide Telescope project
# Licensed under the MIT License.

"""Utilities for parallel processing

from __future__ import absolute_import, division, print_function

__all__ = '''

import multiprocessing as mp
import os
import sys


[docs] def resolve_parallelism(parallel): """Decide what level of parallelism to use. Parameters ---------- parallel : integer or None The user's specification Returns ------- A positive integer giving the parallelization level. """ if parallel is None: if mp.get_start_method() == 'fork': parallel = os.cpu_count() if SHOW_INFORMATIONAL_MESSAGES and parallel > 1: print(f'info: parallelizing processing over {parallel} CPUs') else: parallel = 1 if parallel > 1 and mp.get_start_method() != 'fork': print('''warning: parallel processing was requested but is not possible because this operating system is not using `fork`-based multiprocessing On macOS a bug prevents forking:''', file=sys.stderr) parallel = 1 if parallel > 1: return parallel return 1