Python uses a garbage collector to reclaim memory. Objects don't die just because they fall out of scope, they will be around until the next GC cycle.
You can force the garbage collector with import gc gc.collect() but that is a rather expensive operation so you don't want to do call it all the time. On Wednesday, February 29, 2012 6:30:47 AM UTC-8, Nathann Cohen wrote: > > Hello everybody !!! > > There has been a bug report [1, 2] on "ask Sage" about a memory leak with > CPLEX. I checked, and it is True. But I do not think I know how to patch > that. > > Here is the thing : the dominating_set function (among many others) uses > Linear Programming, and so creates a LP object when it is called. The LP > object *should* disappear by itself when the method returns its result, but > I observed a STRANGE behaviour... > > sage: graphs.PetersenGraph().dominating_set() > IBM ILOG License Manager: "IBM ILOG Optimization Suite for Academic > Initiative" is accessing CPLEX 12 with option(s): "e m b q ". > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: # At this moment I just *do nothing* for a few seconds..... > sage: graphs.PetersenGraph().dominating_set() > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: graphs.PetersenGraph().dominating_set() > [1, 4, 5] > sage: exit > Exiting Sage (CPU time 0m0.27s, Wall time 0m13.47s). > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > __dealloc__ called ! > > Well. With this kind of behaviour, no wonder a loops ends up eating a lot > of memory, but then I do not know what to do anymore... Should I call "del" > explicitely at the end of each function ? Thank you for your help O_o;;; > > Nathann > > [1] http://ask.sagemath.org/question/1170/memory-blowup-with-milp > [2] http://ask.sagemath.org/question/1191/memory-blowup-2 -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
