I have put a patch for this problem as sage-trac ticket 403: http://sagemath.org:9002/sage_trac/ticket/403
I just used the subprocess module instead of popen3, and it seems to have fixed the problem. Similar code appears in three other places, but since I am not familiar with those modules I did not try to fix them. Problems with popen3 seem to occur only if the process takes quite a while to complete - about 10-15 minutes for the issue with polymake. There might also be some similar issues with popen2, which is more heavily used. Eventually these should probably all be changed to use subprocess instead. Search Source Code: popen3 1. geometry/lattice_polytope.py 2. geometry/polytope.py 3. interfaces/ecm.py 4. misc/hg.py -Marshall On Jul 9, 10:35 pm, Hamptonio <[EMAIL PROTECTED]> wrote: > Recently I was doing some middleweight polytope calculations - meaning > stuff that takes about 15 minutes to compute on a nice machine - and > the convex_hull call to polymake began to hang at a certain point. > The faster your machine, the bigger a polytope you need to reproduce > this, but its a pretty robust bug. > > The problem seems to lie in some sort of deadlock with the popen3 call > in the cmd method of the Polytope class in polytope.py. I can "fix" > this by simply deleting the error-checking code and moving the > stdin.close() command - i.e. at the end of the cmd definition I have > > stdin, stdout, stderr = os.popen3(c) > #stdin.close() > #err = stderr.read() > #if len(err) > 0: > # raise RuntimeError, err > ans = stdout.read() > if len(ans) == 0: > raise ValueError, "%s\nError executing polymake command > %s"%( > err,cmd) > stdin.close() > self.__data = open(F).read() > return ans > > and it seems to work fine on my bigger polytopes. In searching the > source, I noticed that there are similar constructions elsewhere, and > so this may be a pervasive problem. > > I have become confused trying to understand the finer points of popen, > popen2, popen3, popen4, and popen2.Popen3, subprocess, > os.system, ....python seems to have a bewildering array of such > functions. I would be interested in any opinions. Doug Hellman seems > to have some clearly written thoughts up at > > http://blog.doughellmann.com/2007/07/pymotw-subprocess.html > > on subprocess. > > If I can get a little help and insight on this I will try to write a > patch. > > -Marshall --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
