1 2 #include <petsc/private/viewerimpl.h> /*I "petscviewer.h" I*/ 3 4 /*@C 5 PetscViewerGetSubViewer - Creates a new PetscViewer (same type as the old) 6 that lives on a subcommunicator 7 8 Collective on PetscViewer 9 10 Input Parameter: 11 . viewer - the PetscViewer to be reproduced 12 13 Output Parameter: 14 . outviewer - new PetscViewer 15 16 Level: advanced 17 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(). 23 24 Call PetscViewerRestoreSubViewer() to destroy this PetscViewer, NOT PetscViewerDestroy() 25 26 This is most commonly used to view a sequential object that is part of a 27 parallel object. For example block Jacobi PC view could use this to obtain a 28 PetscViewer that is used with the sequential KSP on one block of the preconditioner. 29 30 Between the calls to PetscViewerGetSubViewer() and PetscViewerRestoreSubViewer() the original 31 viewer should not be used 32 33 PETSCVIEWERDRAW and PETSCVIEWERBINARY only support returning a singleton viewer on rank 0, 34 all other ranks will return a NULL viewer 35 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. 40 41 It would be nice if the call to PetscViewerFlush() was not required and was handled by 42 PetscViewerRestoreSubViewer() 43 44 .seealso: PetscViewerSocketOpen(), PetscViewerASCIIOpen(), PetscViewerDrawOpen(), PetscViewerRestoreSubViewer() 45 @*/ 46 PetscErrorCode PetscViewerGetSubViewer(PetscViewer viewer,MPI_Comm comm,PetscViewer *outviewer) 47 { 48 PetscErrorCode ierr; 49 50 PetscFunctionBegin; 51 PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,1); 52 PetscValidPointer(outviewer,3); 53 if (viewer->ops->getsubviewer) { 54 ierr = (*viewer->ops->getsubviewer)(viewer,comm,outviewer);CHKERRQ(ierr); 55 } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Cannot get SubViewer PetscViewer for type %s",((PetscObject)viewer)->type_name); 56 PetscFunctionReturn(0); 57 } 58 59 /*@C 60 PetscViewerRestoreSubViewer - Restores a new PetscViewer obtained with PetscViewerGetSubViewer(). 61 62 Collective on PetscViewer 63 64 Input Parameters: 65 + viewer - the PetscViewer that was reproduced 66 - outviewer - new PetscViewer 67 68 Level: advanced 69 70 Notes: 71 Call PetscViewerGetSubViewer() to get this PetscViewer, NOT PetscViewerCreate() 72 73 .seealso: PetscViewerSocketOpen(), PetscViewerASCIIOpen(), PetscViewerDrawOpen(), PetscViewerGetSubViewer() 74 @*/ 75 PetscErrorCode PetscViewerRestoreSubViewer(PetscViewer viewer,MPI_Comm comm,PetscViewer *outviewer) 76 { 77 PetscErrorCode ierr; 78 79 PetscFunctionBegin; 80 PetscValidHeaderSpecific(viewer,PETSC_VIEWER_CLASSID,1); 81 82 if (viewer->ops->restoresubviewer) { 83 ierr = (*viewer->ops->restoresubviewer)(viewer,comm,outviewer);CHKERRQ(ierr); 84 } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"Cannot restore SubViewer PetscViewer for type %s",((PetscObject)viewer)->type_name); 85 PetscFunctionReturn(0); 86 } 87