15c6c1daeSBarry Smith 2af0996ceSBarry Smith #include <petsc/private/viewerimpl.h> /*I "petscviewer.h" I*/ 35c6c1daeSBarry Smith 4b3fa1ec5SBarry Smith /*@C 5*811af0c4SBarry Smith PetscViewerGetSubViewer - Creates a new `PetscViewer` (same type as the old) 63f08860eSBarry Smith that lives on a subcommunicator 75c6c1daeSBarry Smith 8*811af0c4SBarry Smith Collective on viewer 95c6c1daeSBarry Smith 105c6c1daeSBarry Smith Input Parameter: 11*811af0c4SBarry Smith . viewer - the `PetscViewer` to be reproduced 125c6c1daeSBarry Smith 135c6c1daeSBarry Smith Output Parameter: 14*811af0c4SBarry Smith . outviewer - new `PetscViewer` 155c6c1daeSBarry Smith 165c6c1daeSBarry Smith Level: advanced 175c6c1daeSBarry Smith 1895452b02SPatrick Sanan Notes: 19a62913d3SBarry Smith The output of the subviewers is synchronized against the original viewer. For example, if a 20a62913d3SBarry Smith viewer on two MPI ranks is decomposed into two subviewers, the output from the first viewer is 21*811af0c4SBarry Smith all printed before the output from the second viewer. You must call `PetscViewerFlush()` after 22*811af0c4SBarry Smith the call to `PetscViewerRestoreSubViewer()`. 23a62913d3SBarry Smith 24*811af0c4SBarry Smith Call `PetscViewerRestoreSubViewer()` to destroy this `PetscViewer`, NOT `PetscViewerDestroy()` 255c6c1daeSBarry Smith 265c6c1daeSBarry Smith This is most commonly used to view a sequential object that is part of a 27*811af0c4SBarry Smith parallel object. For example `PCView()` on a `PCBJACOBI` could use this to obtain a 28*811af0c4SBarry Smith `PetscViewer` that is used with the sequential `KSP` on one block of the preconditioner. 295c6c1daeSBarry Smith 30*811af0c4SBarry Smith Between the calls to `PetscViewerGetSubViewer()` and `PetscViewerRestoreSubViewer()` the original 31e5afcf28SBarry Smith viewer should not be used 32e5afcf28SBarry Smith 33*811af0c4SBarry Smith `PETSCVIEWERDRAW` and `PETSCVIEWERBINARY` only support returning a singleton viewer on rank 0, 34e5afcf28SBarry Smith all other ranks will return a NULL viewer 35e5afcf28SBarry Smith 36e5afcf28SBarry Smith Developer Notes: 37e5afcf28SBarry Smith There is currently incomplete error checking that the user does not use the original viewer between the 38*811af0c4SBarry Smith the calls to `PetscViewerGetSubViewer()` and `PetscViewerRestoreSubViewer()`. If the user does there 39e5afcf28SBarry Smith could be errors in the viewing that go undetected or crash the code. 40e5afcf28SBarry Smith 41*811af0c4SBarry Smith It would be nice if the call to `PetscViewerFlush()` was not required and was handled by 42*811af0c4SBarry Smith `PetscViewerRestoreSubViewer()` 43a62913d3SBarry Smith 44db781477SPatrick Sanan .seealso: `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerRestoreSubViewer()` 455c6c1daeSBarry Smith @*/ 469371c9d4SSatish Balay PetscErrorCode PetscViewerGetSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer) { 475c6c1daeSBarry Smith PetscFunctionBegin; 485c6c1daeSBarry Smith PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 1); 49064a246eSJacob Faibussowitsch PetscValidPointer(outviewer, 3); 50dbbe0bcdSBarry Smith PetscUseTypeMethod(viewer, getsubviewer, comm, outviewer); 515c6c1daeSBarry Smith PetscFunctionReturn(0); 525c6c1daeSBarry Smith } 535c6c1daeSBarry Smith 54b3fa1ec5SBarry Smith /*@C 55*811af0c4SBarry Smith PetscViewerRestoreSubViewer - Restores a new `PetscViewer` obtained with `PetscViewerGetSubViewer()`. 565c6c1daeSBarry Smith 57*811af0c4SBarry Smith Collective on viewer 585c6c1daeSBarry Smith 595c6c1daeSBarry Smith Input Parameters: 60*811af0c4SBarry Smith + viewer - the `PetscViewer` that was reproduced 61*811af0c4SBarry Smith - outviewer - the subviewer to be returned `PetscViewer` 625c6c1daeSBarry Smith 635c6c1daeSBarry Smith Level: advanced 645c6c1daeSBarry Smith 65db781477SPatrick Sanan .seealso: `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerGetSubViewer()` 665c6c1daeSBarry Smith @*/ 679371c9d4SSatish Balay PetscErrorCode PetscViewerRestoreSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer) { 685c6c1daeSBarry Smith PetscFunctionBegin; 695c6c1daeSBarry Smith PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 1); 70ffc4695bSBarry Smith 71dbbe0bcdSBarry Smith PetscUseTypeMethod(viewer, restoresubviewer, comm, outviewer); 725c6c1daeSBarry Smith PetscFunctionReturn(0); 735c6c1daeSBarry Smith } 74