Thanks Barry We were confused because the online manual says:
PETSc objects are always automatically initialized when declared so you do not need to (and should not) do type(tXXX) x = PETSC_NULL_XXX XXX x = PETSC_NULL_XXX Randy > On Jul 4, 2025, at 6:56 PM, Barry Smith <bsm...@petsc.dev> wrote: > > > You need to pass PETSC_NULL_MAT in those locations, you cannot just pass a > Mat that has never been created (that is a different kind of NULL matrix :-). > I have added clearer error checking in > https://urldefense.us/v3/__https://gitlab.com/petsc/petsc/-/merge_requests/8526__;!!G_uCfscf7eWS!Y7C44Hdmd964boi6gEmciviR7GGeHph-RSlxAgB7oCuxJsPbYDW5gZpHgn5KIJMryLOmkFvMiYX3aDDpI5f6G0AQrg$ > > > Barry > > >> On Jul 4, 2025, at 10:32 AM, Randall Mackie <rlmackie...@gmail.com> wrote: >> >> In the process of upgrading our code to version 3.23, we have run into >> another issue, this time with nest matrices. >> >> In previous versions (well to at least 3.21) it was perfectly fine to pass >> in null matrix blocks to create a nest matrix. There are situations where we >> have, for example, only diagonal blocks. That should be allowed and was and >> worked fine. >> >> In petsc 3.23, that no longer is true, or perhaps we do not know what is the >> proper way to pass in a null matrix. >> >> The attached example reproduces this with the following error: >> >> [0]PETSC ERROR: Configure options: --force --with-clean=1 >> --with-scalar-type=complex --with-debugging=1 --with-fortran=1 >> --download-mpich=1 --with-cxx=0 >> [0]PETSC ERROR: #1 PetscObjectReference() at >> /home/rmackie/PETSc/petsc/src/sys/objects/inherit.c:620 >> [0]PETSC ERROR: #2 MatNestSetSubMats_Nest() at >> /home/rmackie/PETSc/petsc/src/mat/impls/nest/matnest.c:1407 >> [0]PETSC ERROR: #3 MatNestSetSubMats() at >> /home/rmackie/PETSc/petsc/src/mat/impls/nest/matnest.c:1518 >> [0]PETSC ERROR: #4 MatCreateNest() at >> /home/rmackie/PETSc/petsc/src/mat/impls/nest/matnest.c:1800 >> [0]PETSC ERROR: #5 matnest_bug_reproducer.F90:48 >> >> >> Thanks for helping with this, and thanks for all the work on the Fortran >> interfaces - I’ve been playing around with your new branch and am excited by >> all the work! >> >> Randy >> <matnest_bug_reproducer.F90> >
