If I run the following code:
import gc
while True:
P = Polyhedron([[1,0,0,0], [0,1,0,0], [0,0,1,0], [0,0,0,1]])
faces = P.faces(3)
del P, faces
print "memory usage: " + str(get_memory_usage()) + ", gc: " + str(gc.collect())
the memory usage keeps increasing. Do you know what is the cause and how to avoid this problem?
This has been reported previously on sage-devel:
https://sage-devel.narkive.com/O7zoOj...
It is related to the creation of the whole(!) face lattice, even if it is not necessary. This is a problem caused by UniqueRepresentation of posets, see the trac ticket https://trac.sagemath.org/ticket/14356
Meanwhile, from the Sage version 8.9, CombinatorialPolyhedron are available, and one can do the following:
sage: import gc
sage: while True:
....: P = Polyhedron([[1,0,0,0], [0,1,0,0], [0,0,1,0], [0,0,0,1]])
....: CP = CombinatorialPolyhedron(P)
....: faces = list(CP.face_iter(2))
....: del P, CP, faces
....: print("memory usage: " + str(get_memory_usage()) + ", gc: " + str(gc.collect()))
....:
memory usage: 11593.33203125, gc: 269
memory usage: 11593.33203125, gc: 49
memory usage: 11593.33203125, gc: 49
memory usage: 11593.33203125, gc: 49
memory usage: 11593.33203125, gc: 49
memory usage: 11593.33203125, gc: 49
memory usage: 11593.33203125, gc: 49
The current plan is that the method .faces() from Polyhedron will be replaced by the above function which is much faster and does not have a memory leak.
(Note: in the above, I could not put 3 as dimension simply because the iterator requires to be a proper dimension).
Asked: 2019-07-22 16:15:08 +0100
Seen: 730 times
Last updated: Aug 27 '19
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This memory leak in Polyhedron is fixed in this ticket.