Pickling Segmentation Fault/ Inconsistent behaviour

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1

Hi everyone,

to restart a simulation I’m using data pickled in a previous run. To ensure that the meshes are the same, I take a copy of the mesh from a pickled GridFunction. Using this copy a create new FESpace and a new GridFunction into which I copy the data from the pickled GridFunction.

When I try to pickle this new grid function I sometimes get a segmentation fault. Attached is a MWE (run once with ‘restart=False’ and then with ‘True’).

Can anyone help me to avoid these segmentation faults?

Best wishes,
Henry

PS: This inconsistency is both on mac an linux, self build on commits gee9a66d1 and gac4d9b1f (NGSolve 2006).

Attachment: test_pickle_seg_fault.py

2

Update:

The issue seems to stem from the fact that I delete the unpickled GridFunction. I thought this would not be problematic, since I explicitly copy the meshmesh = Mesh(_gfu_pic.space.mesh.ngmesh.Copy())

Is there a better way to copy the mesh?

Best wishes,
Henry

3

Hi Henry,

Thanks for the report and the update. We are on it and already found the issue (it’s about pointers in the netgen::Mesh, which are not correctly set in the copy). The fix will be on master soon.

Best,
Matthias

4

Hi Matthias,

thank for the quick reply and fix :slight_smile: !

Best wishes,
Henry

5

Fix is online, a new release is in the pipeline.
Best,
Matthias