1: #pragma once 3: #include <petscdm.h> 5: PETSC_EXTERN PetscErrorCode DMCreate_Product(DM); 6: PETSC_EXTERN PetscErrorCode DMProductGetDM(DM, PetscInt, DM *); 7: PETSC_EXTERN PetscErrorCode DMProductSetDimensionIndex(DM, PetscInt, PetscInt); 8: PETSC_EXTERN PetscErrorCode DMProductSetDM(DM, PetscInt, DM);