Dear Petsc users/developers,
I'm experiencing a bug when using petsc4py with GPU support. It may be my
mistake in how I set up a AIJCUSPARSE matrix.
For larger matrices, I sometimes encounter a error in assigning matrix values;
the error is thrown in PetscHMapIJVQuerySet().
Here is a minimum snippet that populates a sparse tridiagonal matrix.
```
from petsc4py import PETSc
from scipy.sparse import diags
import numpy as np
n = int(5e5);
nnz = 3 * np.ones(n, dtype=np.int32); nnz[0] = nnz[-1] = 2
A = PETSc.Mat(comm=PETSc.COMM_WORLD)
A.createAIJ(size=[n,n],comm=PETSc.COMM_WORLD,nnz=nnz)
A.setType('aijcusparse')
tmp = diags([-1,2,-1],[-1,0,+1],shape=(n,n)).tocsr()
A.setValuesCSR(tmp.indptr,tmp.indices,tmp.data)
####### this is the line where the error is thrown.
A.assemble()
```
The error trace is below:
```
File "petsc4py/PETSc/Mat.pyx", line 2603, in petsc4py.PETSc.Mat.setValuesCSR
File "petsc4py/PETSc/petscmat.pxi", line 1039, in
petsc4py.PETSc.matsetvalues_csr
File "petsc4py/PETSc/petscmat.pxi", line 1032, in
petsc4py.PETSc.matsetvalues_ijv
petsc4py.PETSc.Error: error code 76
[0] MatSetValues() at
/work/06368/annayesy/ls6/petsc/src/mat/interface/matrix.c:1497
[0] MatSetValues_Seq_Hash() at
/work/06368/annayesy/ls6/petsc/include/../src/mat/impls/aij/seq/seqhashmatsetvalues.h:52
[0] PetscHMapIJVQuerySet() at
/work/06368/annayesy/ls6/petsc/include/petsc/private/hashmapijv.h:10
[0] Error in external library
[0] [khash] Assertion: `ret >= 0' failed.
```
If I run the same script a handful of times, it will run without errors
eventually.
Does anyone have insight on why it is behaving this way? I'm running on a node
with 3x NVIDIA A100 PCIE 40GB.
Thank you!
Anna
