[petsc-users] MatSetSizes: C vs python

[Stefano Zampini]

The right call in petsc4py is


P.setSizes(((nrowsLoc,PETSc.DECIDE),(ncolsLoc,PETSc.DECIDE)),1)


https://petsc.org/main/petsc4py/reference/petsc4py.PETSc.Mat.html#petsc4py.PETSc.Mat.setSizes

Il giorno mar 6 giu 2023 alle ore 13:05 Blaise Bourdin <bourdin at mcmaster.ca>
ha scritto:

> Hi,
>
> Does anybody understand why MatSetSizes seem to behave differently in C
> and python?
>
> I would expect the attached examples to be strictly equivalent but the
> python version fails in parallel. It may be that the python interface is
> different, but I don’t see any mention of this in the python docs.
>
> Regards,
> Blaise
>
>
> SiBookPro:test (master)$ mpirun -np 2 python3 testL2G2.py  nrowsLoc: 10
> ncolsLoc: 20
> Traceback (most recent call last):
>   File "/Users/blaise/Development/ccG_CR/test/testL2G2.py", line 20, in
> <module>
> nrowsLoc: 11 ncolsLoc: 21
> Traceback (most recent call last):
>   File "/Users/blaise/Development/ccG_CR/test/testL2G2.py", line 20, in
> <module>
>     sys.exit(main())
>     sys.exit(main())
>              ^^^^^^
>   File "/Users/blaise/Development/ccG_CR/test/testL2G2.py", line 12, in
> main
>              ^^^^^^
>   File "/Users/blaise/Development/ccG_CR/test/testL2G2.py", line 12, in
> main
>     P.setSizes([nrowsLoc,ncolsLoc],1)
>     P.setSizes([nrowsLoc,ncolsLoc],1)
>   File "petsc4py/PETSc/Mat.pyx", line 323, in petsc4py.PETSc.Mat.setSizes
> petsc4py.PETSc.Error: error code 62
> [1] MatSetSizes() at /opt/HPC/petsc-release/src/mat/utils/gcreate.c:161
> [1] Invalid argument
> [1] Int value must be same on all processes, argument # 4
>   File "petsc4py/PETSc/Mat.pyx", line 323, in petsc4py.PETSc.Mat.setSizes
> petsc4py.PETSc.Error: error code 62
> [0] MatSetSizes() at /opt/HPC/petsc-release/src/mat/utils/gcreate.c:161
> [0] Invalid argument
> [0] Int value must be same on all processes, argument # 4
>
>
>
>
> —
> Canada Research Chair in Mathematical and Computational Aspects of Solid
> Mechanics (Tier 1)
> Professor, Department of Mathematics & Statistics
> Hamilton Hall room 409A, McMaster University
> 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
> https://www.math.mcmaster.ca/bourdin | +1 (905) 525 9140 ext. 27243
>
>

-- 
Stefano
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