Multiple errors on Windows 10

[bobturneruk]

Running:

python test_trace.py

results in numerous errors e.g.

RuntimeError
The above exception was the direct cause of the following exception:

: Traceback (most recent call last):

        An attempt has been made to start a new process before the
        current process has finished its bootstrapping phase.

        This probably means that you are not using fork to start your
        child processes and you have forgotten to use the proper idiom
        in the main module:

            if __name__ == '__main__':
                freeze_support()
                ...

        The "freeze_support()" line can be omitted if the program
        is not going to be frozen to produce an executable.  File "<string>", line 1, in <module>


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 116, in spawn_main
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 125, in _main
    exitcode = _main(fd, parent_sentinel)
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 125, in _main
    prepare(preparation_data)
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 236, in prepare
    prepare(preparation_data)
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 236, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 287, in _fixup_main_from_path
        _fixup_main_from_path(data['init_main_from_path'])main_content = runpy.run_path(main_path,

  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\multiprocess\spawn.py", line 287, in _fixup_main_from_path
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 265, in run_path
        main_content = runpy.run_path(main_path,return _run_module_code(code, init_globals, run_name,

  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 265, in run_path
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 97, in _run_module_code
        _run_code(code, mod_globals, init_globals,return _run_module_code(code, init_globals, run_name,

  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 87, in _run_code
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 97, in _run_module_code
        exec(code, run_globals)_run_code(code, mod_globals, init_globals,

  File "C:\Users\bobturner\Documents\causcumber\scenarios\basic-end2end\test_trace.py", line 156, in <module>
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\runpy.py", line 87, in _run_code
        exec(code, run_globals)run_covasim("Baseline", base_params.copy(), [])

  File "C:\Users\bobturner\Documents\causcumber\scenarios\basic-end2end\test_trace.py", line 156, in <module>
  File "C:\Users\bobturner\Documents\causcumber\scenarios\basic-end2end\test_trace.py", line 84, in run_covasim
        run_covasim("Baseline", base_params.copy(), [])intervention_sim.run(n_runs=n_runs, verbose=0)

  File "C:\Users\bobturner\Documents\causcumber\scenarios\basic-end2end\test_trace.py", line 84, in run_covasim
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 167, in run
    intervention_sim.run(n_runs=n_runs, verbose=0)
self.sims = multi_run(sims, **kwargs)  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 167, in run

  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 1468, in multi_run
    self.sims = multi_run(sims, **kwargs)
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 1468, in multi_run
    raise E
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 1449, in multi_run
        raise Esims = sc.parallelize(single_run, iterkwargs=iterkwargs, kwargs=kwargs, **par_args) # Run in parallel

  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\covasim\run.py", line 1449, in multi_run
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\sciris\sc_parallel.py", line 285, in parallelize
    raise RuntimeError(errormsg) from E
RuntimeError:
 Uh oh! It appears you are trying to run with multiprocessing on Windows outside
 of the __main__ block; please see https://docs.python.org/3/library/multiprocessing.html
 for more information. The correct syntax to use is e.g.

 import sciris as sc

 def my_func(x):
     return

 if __name__ == '__main__':
     sc.parallelize(my_func)

sims = sc.parallelize(single_run, iterkwargs=iterkwargs, kwargs=kwargs, **par_args) # Run in parallel
  File "C:\Users\bobturner\.conda\envs\causcumber\lib\site-packages\sciris\sc_parallel.py", line 285, in parallelize
    raise RuntimeError(errormsg) from E
RuntimeError:
 Uh oh! It appears you are trying to run with multiprocessing on Windows outside
 of the __main__ block; please see https://docs.python.org/3/library/multiprocessing.html
 for more information. The correct syntax to use is e.g.

 import sciris as sc

 def my_func(x):
     return

 if __name__ == '__main__':
     sc.parallelize(my_func)

[bobturneruk]

This may be a covasim issue.

[jmafoster1]

Yeah I think it is a covasim issue. What are you using to run the program? I find I get that kind of issue on Spyder sometimes but never if I run it from the terminal.

[bobturneruk]

Terminal. Python 3.8, Windows 10. I typically don't use Spyder - VSCode is my IDE of choice. I'm adaptable, though!

[bobturneruk]

I'll investigate further,

[jmafoster1]

That's really weird, then. The issues do look to be Windows specific, so I'm afraid I can't help you. I've not used Windows for years. Maybe see if you can run the basic covasim tutorials on your machine, and then create an issue over there if it's still not working?

[bobturneruk]

Yes. I'm fine with whatever OS, but I'll try and pin this down.

[AndrewC19]

This is a Covasim issue. Multiprocessing on Windows is strange so we need to run covasim from within a main block. We should do this everywhere to ensure compatability with Windows.

The issue is explained here.

I'll open a PR with a fix.