python

subprocess wildcard usage

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import os import subprocess proc = subprocess.Popen(['ls','*.bc'], stdout=subprocess.PIPE, stderr=subprocess.PIPE) out,err = proc.communicate() print out This script should print all the files with .bc suffix however it returns an empty list. If I do ls *.bc manually in the command line it works. Doing [‘ls’,’test.bc’] inside the script works as well but for some reason the … Read more

Python multiprocessing safely writing to a file

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I am trying to solve a big numerical problem which involves lots of subproblems, and I’m using Python’s multiprocessing module (specifically Pool.map) to split up different independent subproblems onto different cores. Each subproblem involves computing lots of sub-subproblems, and I’m trying to effectively memoize these results by storing them to a file if they have not been computed by any process yet, otherwise skip the computation and just read the results from the file.