R stuck when calling a python function with multiprocessing module using reticulate

[doorholez]

I am trying to call a python function with a multiprocessing module, but R always stucks when calling the function.
Here is a simple example to replicate the problem.
python script (test.py):

from multiprocessing import Pool
def f(a):
    print(a)
    return a ** 2
def f2():
    p = Pool(5)
    rtn = p.map(f, [1,2,3,4,5])
    return rtn
if __name__ == "__main__":
    print(f2())

R script (test.R):

test_py = reticulate::import("test1")
print("Processing python program...")
rlt = test_py$f2()
print("Python program finished.")

I can run the python script in python, but R always stucks in the line 'test_py$f2()'
Can you please guide me how to call python function with multiprocessing module in R?
Thanks.

[t-kalinowski]

Hi, thank you for the helpful reprex. Unfortunately I can't reproduce the error, either in the terminal or the RStudio IDE. Can you please share more details about your environment (e.g., sessioninfo::sessioninfo())?

[doorholez]

Oh, I tried it on the linux server and it works. But it still not working and stuck on my Windows PC. I noticed that when I run the script, the CPU usage of Windows Defender comes high. Maybe that's the problem? Here is my Windows PC environment:

- Session info -------------------------------------------------------------
 setting  value
 version  R version 4.2.2 (2022-10-31 ucrt)
 os       Windows 10 x64 (build 19045)
 system   x86_64, mingw32
 ui       RStudio
 language (EN)
 collate  Chinese (Simplified)_China.936
 ctype    Chinese (Simplified)_China.936
 tz       Asia/Taipei
 date     2023-03-16
 rstudio  2021.09.1+372 Ghost Orchid (desktop)
 pandoc   NA

- Packages -----------------------------------------------------------------
 package     * version date (UTC) lib source
 cli           3.6.0   2023-01-09 [1] CRAN (R 4.2.2)
 sessioninfo   1.2.2   2021-12-06 [1] CRAN (R 4.2.2)

 [1] C:/Users/66437/AppData/Local/R/win-library/4.2
 [2] D:/R/R-4.2.2/library

----------------------------------------------------------------------------

And here is the screenshot of task manager. You can see the Window Defender is running automatically.

[doorholez]

Besides,it seems to appear on others Windows PC. I also reproduced it on the Windows 11 OS and I find another guy with the same problem. https://stackoverflow.com/questions/73777013/how-can-i-successfully-call-python-script-in-r-using-reticulate-when-having-m

[t-kalinowski]

I believe this was fixed with #1461.
Please try the development version of reticulate

remotes::install_github("rstudio/reticulate")