13   Mat          A, A11, A12, A21, A22;  in main()  local
77   PetscCall(MatCreate(PETSC_COMM_SELF, &A21));  in main()
78   PetscCall(MatSetSizes(A21, size2, size1, size2, size1));  in main()
79   PetscCall(MatSetType(A21, MATSEQDENSE));  in main()
80   PetscCall(MatSeqDenseSetPreallocation(A21, b + size1));  in main()
81   PetscCall(MatDenseSetLDA(A21, size));  in main()
82   PetscCall(MatAssemblyBegin(A21, MAT_FINAL_ASSEMBLY));  in main()
83   PetscCall(MatAssemblyEnd(A21, MAT_FINAL_ASSEMBLY));  in main()
106   PetscCall(MatMultAdd(A21, X1, Z2, Z2));  in main()
136   PetscCall(MatMultAdd(A21, X1, Z2, Z2));  in main()
146   PetscCall(MatMultTransposeAdd(A21, X2, Z1, Z1));  in main()
160   PetscCall(MatDestroy(&A21));  in main()