Alejandro : Fixed https://bitbucket.org/petsc/petsc/commits/0043d7fe17a5a8a1e4768ab560023392b3862352 It will merged to petsc-release after our nightly tests.
Your detailed report is very helpful, thanks! Hong Hi, > > After updating petsc from version 3.6.2 to 3.7, I had the following > problem: > > The result that I get from doing something like > MatMult(schurComplement,v1,v2); differs between the petsc versions that I > mentioned. I traced back the problem to the function > MatGetSubMatrices_SeqSBAIJ(). What I did in order to temporarily solve my > problem was to use in petsc 3.7 the code of MatGetSubMatrices_SeqSBAIJ() > corresponding to petsc 3.6.2. > > How I solved the problem is not a real solution, but it allows me to keep > working. My question is: is it a bug or do you think that there could be > something wrong with my code from which I use petsc? > > I think it should be a bug. If I run the ksp example 59 which uses FETI-DP > (whose implementation also uses something like > MatMult(schurComplement,v1,v2)) with petsc 3.7, I get the following > unexpected answer > > mpiexec -n 4 ./ex59 -npx 2 -npy 2 -nex 60 -ney 60 -ksp_max_it 3 > ------------------FETI-DP stats------------------------------- > Number of degrees of freedom : 355 > Number of iterations : 3 > Eigenvalues preconditioned operator : 1.49e+00 8.86e+00 > Error betweeen exact and computed solution : 1.91e+00 > -------------------------------------------------------------- > > If I run the same problem with petsc 3.7 but with > MatGetSubMatrices_SeqSBAIJ() corresponding to petsc 3.6.2, I get the > expected answer > > mpiexec -n 4 ./ex59 -npx 2 -npy 2 -nex 60 -ney 60 -ksp_max_it 3 > ------------------FETI-DP stats------------------------------- > Number of degrees of freedom : 355 > Number of iterations : 3 > Eigenvalues preconditioned operator : 1.08e+00 2.08e+00 > Error betweeen exact and computed solution : 3.60e-02 > -------------------------------------------------------------- > > > Thanks, > Alejandro >
