Pierre, When we do MatProductCreate: C = A*B; //C owns A and B, thus B->refct =2 MatProductCreateWithMats: B = A*C; //If I let B own A and C, then C->refct=2 Then MatDestroy(&B) and MatDestroy(&C) only reduce their refct from 2 to 1, thus memory leak. My solution is adding { matreference; /* do not add refct when using MatProductCreateWithMat() to void recursive references */ } Mat_Product This flg prevents MatProductCreateWithMats() to increase reference counts, i.e., B does not own A and C to avoid reverse ownership. I am not sure this is a reasonable solution. Let me know if you have better solution. See ex109.c and ex195.c for tests. Hong ________________________________ From: Pierre Jolivet <pierre.joli...@enseeiht.fr> Sent: Saturday, April 25, 2020 11:45 AM To: Zhang, Hong <hzh...@mcs.anl.gov> Cc: Jose E. Roman <jro...@dsic.upv.es>; Stefano Zampini <stefano.zamp...@gmail.com>; petsc-dev <petsc-dev@mcs.anl.gov>; Smith, Barry F. <bsm...@mcs.anl.gov> Subject: Re: [petsc-dev] MATOP_MAT_MULT
Hong, José didn’t report this, though he may have run into the same issue, I did. I’ll try the branch and get back at you on GitLab MR. Thanks, Pierre On 25 Apr 2020, at 6:17 PM, Zhang, Hong <hzh...@mcs.anl.gov<mailto:hzh...@mcs.anl.gov>> wrote: Jose, >> I also now just tested some previously PETSC_VERSION_LT(3,13,0) running code >> with C=A*B, Dense=Nest*Dense, all previously allocated prior to a call to >> MatMatMult and scall = MAT_REUSE_MATRIX. >> Sadly, it’s now broken. It is my fault for not having a test for this in >> https://gitlab.com/petsc/petsc/-/merge_requests/2069, sorry about that. >> [0]PETSC ERROR: Call MatProductSymbolic() first >> [0]PETSC ERROR: #1 MatProductNumeric() line 730 in >> /ccc/work/cont003/rndm/rndm/petsc/src/mat/interface/matproduct.c >> [0]PETSC ERROR: #2 MatMatMult() line 9335 in >> /ccc/work/cont003/rndm/rndm/petsc/src/mat/interface/matrix.c >> >> Here is a reproducer (that will work OK with 3.12.4). >> diff --git a/src/mat/tests/ex195.c b/src/mat/tests/ex195.c >> index c72662bc3c..811de669c5 100644 >> --- a/src/mat/tests/ex195.c >> +++ b/src/mat/tests/ex195.c >> @@ -73,2 +73,3 @@ int main(int argc,char **args) >> ierr = MatMatMult(nest,B,MAT_REUSE_MATRIX,PETSC_DEFAULT,&C);CHKERRQ(ierr); >> + ierr = MatMatMult(nest,C,MAT_REUSE_MATRIX,PETSC_DEFAULT,&B);CHKERRQ(ierr); >> ierr = MatMatMultEqual(nest,B,C,10,&equal);CHKERRQ(ierr); >> >> $ make -f gmakefile test searchin=mat_tests-ex195 >> >> I believe this is very close to the topic at hand and issue #608, so maybe >> you could fix this as well in the same upcoming MR? Just let me know, I can >> have a crack it otherwise. This is a bug. I fixed it in the branch hzhang/fix-matproduct-reuse/maint. Can you test it? Hong