15c6c1daeSBarry Smith 2af0996ceSBarry Smith #include <petsc/private/viewerimpl.h> /*I "petscviewer.h" I*/ 35c6c1daeSBarry Smith 4b3fa1ec5SBarry Smith /*@C 5811af0c4SBarry Smith PetscViewerGetSubViewer - Creates a new `PetscViewer` (same type as the old) 63f08860eSBarry Smith that lives on a subcommunicator 75c6c1daeSBarry Smith 8*c3339decSBarry Smith Collective 95c6c1daeSBarry Smith 105c6c1daeSBarry Smith Input Parameter: 11811af0c4SBarry Smith . viewer - the `PetscViewer` to be reproduced 125c6c1daeSBarry Smith 135c6c1daeSBarry Smith Output Parameter: 14811af0c4SBarry 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 21811af0c4SBarry Smith all printed before the output from the second viewer. You must call `PetscViewerFlush()` after 22811af0c4SBarry Smith the call to `PetscViewerRestoreSubViewer()`. 23a62913d3SBarry Smith 24811af0c4SBarry 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 27811af0c4SBarry Smith parallel object. For example `PCView()` on a `PCBJACOBI` could use this to obtain a 28811af0c4SBarry Smith `PetscViewer` that is used with the sequential `KSP` on one block of the preconditioner. 295c6c1daeSBarry Smith 30811af0c4SBarry Smith Between the calls to `PetscViewerGetSubViewer()` and `PetscViewerRestoreSubViewer()` the original 31e5afcf28SBarry Smith viewer should not be used 32e5afcf28SBarry Smith 33811af0c4SBarry 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 38811af0c4SBarry 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 41811af0c4SBarry Smith It would be nice if the call to `PetscViewerFlush()` was not required and was handled by 42811af0c4SBarry Smith `PetscViewerRestoreSubViewer()` 43a62913d3SBarry Smith 44db781477SPatrick Sanan .seealso: `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerRestoreSubViewer()` 455c6c1daeSBarry Smith @*/ 46d71ae5a4SJacob Faibussowitsch PetscErrorCode PetscViewerGetSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer) 47d71ae5a4SJacob Faibussowitsch { 485c6c1daeSBarry Smith PetscFunctionBegin; 495c6c1daeSBarry Smith PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 1); 50064a246eSJacob Faibussowitsch PetscValidPointer(outviewer, 3); 51dbbe0bcdSBarry Smith PetscUseTypeMethod(viewer, getsubviewer, comm, outviewer); 525c6c1daeSBarry Smith PetscFunctionReturn(0); 535c6c1daeSBarry Smith } 545c6c1daeSBarry Smith 55b3fa1ec5SBarry Smith /*@C 56811af0c4SBarry Smith PetscViewerRestoreSubViewer - Restores a new `PetscViewer` obtained with `PetscViewerGetSubViewer()`. 575c6c1daeSBarry Smith 58*c3339decSBarry Smith Collective 595c6c1daeSBarry Smith 605c6c1daeSBarry Smith Input Parameters: 61811af0c4SBarry Smith + viewer - the `PetscViewer` that was reproduced 62811af0c4SBarry Smith - outviewer - the subviewer to be returned `PetscViewer` 635c6c1daeSBarry Smith 645c6c1daeSBarry Smith Level: advanced 655c6c1daeSBarry Smith 66db781477SPatrick Sanan .seealso: `PetscViewerSocketOpen()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewerGetSubViewer()` 675c6c1daeSBarry Smith @*/ 68d71ae5a4SJacob Faibussowitsch PetscErrorCode PetscViewerRestoreSubViewer(PetscViewer viewer, MPI_Comm comm, PetscViewer *outviewer) 69d71ae5a4SJacob Faibussowitsch { 705c6c1daeSBarry Smith PetscFunctionBegin; 715c6c1daeSBarry Smith PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 1); 72ffc4695bSBarry Smith 73dbbe0bcdSBarry Smith PetscUseTypeMethod(viewer, restoresubviewer, comm, outviewer); 745c6c1daeSBarry Smith PetscFunctionReturn(0); 755c6c1daeSBarry Smith } 76