588     IS        Ais[2], Bis[2];  in main()  local
626     PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, n0, idx0, PETSC_OWN_POINTER, &Ais[0]));  in main()
627     PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, n1, idx1, PETSC_OWN_POINTER, &Ais[1]));  in main()
630     PetscCall(MatIncreaseOverlap(A, 2, Ais, 3));  in main()
633     PetscCall(ISSort(Ais[0]));  in main()
634     PetscCall(ISSort(Ais[1]));  in main()
637     PetscCall(ISView(Ais[0], NULL));  in main()
639     PetscCall(ISView(Ais[1], NULL));  in main()
641     PetscCall(MatCreateSubMatrices(A, 2, Ais, Ais, MAT_INITIAL_MATRIX, &Asub));  in main()
642     PetscCall(MatCreateSubMatrices(B, 2, Bis, Ais, MAT_INITIAL_MATRIX, &Bsub));  in main()
647     PetscCall(ISDestroy(&Ais[0]));  in main()
648     PetscCall(ISDestroy(&Ais[1]));  in main()