339     Mat B2, T3, T4;  in main()  local
347 …all(MatDenseGetSubMatrix(B2, PETSC_DECIDE, PETSC_DECIDE, PetscMin(1, K - 1), PetscMin(2, K), &T3));  in main()
349     PetscCall(MatAXPY(T3, -1.0, T, SAME_NONZERO_PATTERN));  in main()
350     PetscCall(MatNorm(T3, NORM_FROBENIUS, &err));  in main()
353       PetscCall(MatView(T3, NULL));  in main()
357     PetscCall(MatDenseRestoreSubMatrix(B2, &T3));  in main()
368 … PetscCall(MatDenseGetSubMatrix(B2, N - 2, PETSC_DECIDE, PetscMin(1, K - 1), PetscMin(2, K), &T3));  in main()
370       PetscCall(MatAXPY(T3, -1.0, T, SAME_NONZERO_PATTERN));  in main()
371       PetscCall(MatNorm(T3, NORM_FROBENIUS, &err));  in main()
374         PetscCall(MatView(T3, NULL));  in main()
378       PetscCall(MatDenseRestoreSubMatrix(B2, &T3));  in main()
388       PetscCall(MatDenseGetSubMatrix(B2, PETSC_DECIDE, 2, PetscMin(1, K - 1), PetscMin(2, K), &T3));  in main()
390       PetscCall(MatAXPY(T3, -1.0, T, SAME_NONZERO_PATTERN));  in main()
391       PetscCall(MatNorm(T3, NORM_FROBENIUS, &err));  in main()
394         PetscCall(MatView(T3, NULL));  in main()
398       PetscCall(MatDenseRestoreSubMatrix(B2, &T3));  in main()