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The default-spawn-method differs by operating system, but usually multiple options are available: https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
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edit approved Jun 28, 2023 at 21:24
julaine
edit approved Jun 28, 2023 at 21:24
julaine
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Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly when the process-creation method is set to 'spawn' which is the default on ms-windows and macOS but also available on linux. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process, and the __name__ mechanism ensures that.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process, and the __name__ mechanism ensures that.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly when the process-creation method is set to 'spawn' which is the default on ms-windows and macOS but also available on linux. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process, and the __name__ mechanism ensures that.

added 43 characters in body
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Roland Smith
Roland Smith
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Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process, and the __name__ mechanism ensures that.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process, and the __name__ mechanism ensures that.

deleted 54 characters in body
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Roland Smith
Roland Smith
  • 43.8k
  • 3
  • 69
  • 98

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 INTERVAL = list(range(10))  def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break istart =+= random.choicerandrange(INTERVAL) start = start +0, i10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 INTERVAL = list(range(10))  def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break i = random.choice(INTERVAL) start = start + i print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process.

Use an Event to govern if the processes should keep running.

Basically, it replaces succ with something that works over all processes.

import multiprocessing import random FIND = 50 MAX_COUNT = 1000 def find(process, initial, return_dict, run): while run.is_set(): start = initial while start <= MAX_COUNT: if FIND == start: return_dict[process] = f"Found: {process}, start: {initial}" run.clear() # Stop running. break start += random.randrange(0, 10) print(start) if __name__ == "__main__": processes = [] manager = multiprocessing.Manager() return_code = manager.dict() run = manager.Event() run.set() # We should keep running. for i in range(5): process = multiprocessing.Process( target=find, args=(f"computer_{i}", i, return_code, run) ) processes.append(process) process.start() for process in processes: process.join() print(return_code.values())

Note that using __name__ is mandatory for multiprocessing to work properly on ms-windows and macOS. On those systems, the main module is imported into newly created Python processes. This needs to happen without side effects such as starting a process.

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Roland Smith
Roland Smith
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  • 69
  • 98