Philip Smith wrote: > Hi > > I use Activestate Python (2.4.3) in a Windows 32 bit environment. > > I have a problem with a large programme that uses a lot of memory > (numerous large arrays which are dynamically extended). I keep getting > unpredictable crashes (on a machine with 1/2 GB memory) whereas on my > laptop (1 GB memory) it seems OK.
I'm way out of my expertise here but I'll give it a try... Is your program pure Python or are you using C extensions (other than the ones in the standard library)? If it is pure Python I think this would be considered a Python bug and would interest the Python developers. > The portion of the code which crashes varies a bit but curiously is > NEVER a part where any memory allocation is happening. Can you post any code? If you can make a short test program that shows the problem that will dramatically increase your chances of getting useful help. > I have to say I have noticed (the programme is basically a > batch-factoring programme for integers) that no matter how I tune gc I > can't get it to reliably free memory in between factoring each integer. I don't think Python will ever release memory back to the OS. This has changed in Python 2.5, you might be interested in trying the alpha release: http://docs.python.org/dev/whatsnew/section-other.html http://www.python.org/download/releases/2.5/ > > Because this is a development programme (and for performance reasons) I > use global variables some of which refer to the large arrays. > > My questions are: > > 1) Does the mere fact that a function cites a variable as global > create a reference which prevents it being collected by gc? You mean a 'global' statement without actually using the named variable? I don't know if this creates a reference, but if so, the reference should go out of scope when the function exits. > 5) Does anyone have ANY suggestions please? These links might be interesting: http://tinyurl.com/pszzh http://evanjones.ca/python-memory.html http://pysizer.8325.org/ Asking on comp.lang.python will give you access to many more people familiar with Python internals than you will find on this list. > > I'm keen to solve this because I would like to make my programme > generally available - in every other respect its near complete and > massively outperforms the only other comparable pure python module > (nzmath) which does the same job. > > Thanks in anticipation. > > Phil > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
