Actual source code: dupl.c
2: #include <petsc/private/viewerimpl.h>
4: /*@C
5: PetscViewerGetSubViewer - Creates a new `PetscViewer` (same type as the old)
6: that lives on a subcommunicator
8: Collective
10: Input Parameter:
11: . viewer - the `PetscViewer` to be reproduced
13: Output Parameter:
14: . outviewer - new `PetscViewer`
16: Level: advanced
18: Notes:
19: The output of the subviewers is synchronized against the original viewer. For example, if a
20: viewer on two MPI ranks is decomposed into two subviewers, the output from the first viewer is
21: all printed before the output from the second viewer. You must call `PetscViewerFlush()` after
22: the call to `PetscViewerRestoreSubViewer()`.
24: Call `PetscViewerRestoreSubViewer()` to destroy this `PetscViewer`, NOT `PetscViewerDestroy()`
26: This is most commonly used to view a sequential object that is part of a
27: parallel object. For example `PCView()` on a `PCBJACOBI` could use this to obtain a
28: `PetscViewer` that is used with the sequential `KSP` on one block of the preconditioner.
30: Between the calls to `PetscViewerGetSubViewer()` and `PetscViewerRestoreSubViewer()` the original
31: viewer should not be used
33: `PETSCVIEWERDRAW` and `PETSCVIEWERBINARY` only support returning a singleton viewer on rank 0,
34: all other ranks will return a NULL viewer
36: Developer Notes:
37: There is currently incomplete error checking that the user does not use the original viewer between the
38: the calls to `PetscViewerGetSubViewer()` and `PetscViewerRestoreSubViewer()`. If the user does there
39: could be errors in the viewing that go undetected or crash the code.
41: It would be nice if the call to `PetscViewerFlush()` was not required and was handled by
42: `PetscViewerRestoreSubViewer()`
44: .seealso: [](sec_viewers), `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerRestoreSubViewer()`
45: @*/
46: PetscErrorCode PetscViewerGetSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer)
47: {
50: PetscUseTypeMethod(viewer, getsubviewer, comm, outviewer);
51: return 0;
52: }
54: /*@C
55: PetscViewerRestoreSubViewer - Restores a new `PetscViewer` obtained with `PetscViewerGetSubViewer()`.
57: Collective
59: Input Parameters:
60: + viewer - the `PetscViewer` that was reproduced
61: - outviewer - the subviewer to be returned `PetscViewer`
63: Level: advanced
65: .seealso: [](sec_viewers), `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerGetSubViewer()`
66: @*/
67: PetscErrorCode PetscViewerRestoreSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer)
68: {
71: PetscUseTypeMethod(viewer, restoresubviewer, comm, outviewer);
72: return 0;
73: }