588     IS        Ais[2], Bis[2];  in main()  local
628     PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, n0, idx0, PETSC_COPY_VALUES, &Bis[0]));  in main()
629     PetscCall(ISCreateGeneral(PETSC_COMM_WORLD, n1, idx1, PETSC_COPY_VALUES, &Bis[1]));  in main()
631     PetscCall(MatIncreaseOverlap(B, 2, Bis, 3));  in main()
635     PetscCall(ISSort(Bis[0]));  in main()
636     PetscCall(ISSort(Bis[1]));  in main()
638     PetscCall(ISView(Bis[0], NULL));  in main()
640     PetscCall(ISView(Bis[1], NULL));  in main()
642     PetscCall(MatCreateSubMatrices(B, 2, Bis, Ais, MAT_INITIAL_MATRIX, &Bsub));  in main()
649     PetscCall(ISDestroy(&Bis[0]));  in main()
650     PetscCall(ISDestroy(&Bis[1]));  in main()