On Tue, Mar 4, 2014 at 3:43 PM, Xiangdong <[email protected]> wrote:
> If I use VecView and write the vector into vtk file, is this done in > parallel or serial? Does each processor send the data to processor 0 and > let it write to the disk? > > Is it possible to let each processor write its own portion and merge them > together later? > I urge you strongly to avoid premature optimization and worrying. If you want to discuss details that is fine, but I do not think the fears expressed above are grounded in reality. Network bandwidth is at least as good as memory bandwidth, so sending to proc 0 is not a problem below 10,000 procs or so. You might think serializing the disk writes would be, but its very likely your machine is doing that anyway by having a small number (usually 1) of I/O nodes. For high core counts we can use MPI I/O which you can turn on with a command line argument. Matt > Thank you. > > Xiangdong > > > On Tue, Mar 4, 2014 at 2:06 PM, Matthew Knepley <[email protected]> wrote: > >> On Tue, Mar 4, 2014 at 12:58 PM, Xiangdong <[email protected]> wrote: >> >>> Thanks, Matt. >>> >>> Given that the FILE_MODE_APPEND is not supported for VTK format, is it >>> possible to write two vectors into the same VTK data file? >>> >> >> Yes, just call VecView() twice. >> >> Matt >> >> >>> Thank you. >>> >>> Xiangdong >>> >>> >>> On Tue, Mar 4, 2014 at 1:52 PM, Matthew Knepley <[email protected]>wrote: >>> >>>> On Tue, Mar 4, 2014 at 12:31 PM, Xiangdong <[email protected]> wrote: >>>> >>>>> What is the difference between PetscViewerSetType and >>>>> PetscViewerSetFormat? It seems that the first one take argument like >>>>> PETSCVIEWERVTK, while the second one takes PETSC_VIEWER_VTK_VTS. >>>>> >>>> >>>> A viewer type is the object type, just like other PETSc object, e.g. >>>> KSP. The format is a particular version >>>> of that output. For example, ASCII viewer is a type, whereas Matlab is >>>> a format. >>>> >>>> >>>>> By the way, how can I find a full list of formats? Clearly, >>>>> PETSC_VIEWER_VTK_VTS is not listed in online documentation for >>>>> PetscViewerSetFormat >>>>> >>>>> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Viewer/PetscViewerSetFormat.html >>>>> >>>> >>>> It is listed in the complete list: >>>> >>>> >>>> http://www.mcs.anl.gov/petsc/petsc-dev/docs/manualpages/Viewer/PetscViewerFormat.html >>>> >>>> Matt >>>> >>>> >>>>> Thank you. >>>>> >>>>> Xiangdong >>>>> >>>>> >>>>> On Tue, Mar 4, 2014 at 1:02 PM, Matthew Knepley <[email protected]>wrote: >>>>> >>>>>> On Tue, Mar 4, 2014 at 11:44 AM, Xiangdong <[email protected]>wrote: >>>>>> >>>>>>> Hello everyone, >>>>>>> >>>>>>> When I use PetsViewerVTKOpen to output vec in vtk format, is it in >>>>>>> ASCII format or binary format? Are there any options to choose between >>>>>>> them? >>>>>>> >>>>>> >>>>>> It is determined by the format, e.g. PETSC_VIEWER_VTK_VTU. >>>>>> >>>>>> Matt >>>>>> >>>>>> >>>>>>> Thank you. >>>>>>> >>>>>>> Xiangdong >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> What most experimenters take for granted before they begin their >>>>>> experiments is infinitely more interesting than any results to which >>>>>> their >>>>>> experiments lead. >>>>>> -- Norbert Wiener >>>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> What most experimenters take for granted before they begin their >>>> experiments is infinitely more interesting than any results to which their >>>> experiments lead. >>>> -- Norbert Wiener >>>> >>> >>> >> >> >> -- >> What most experimenters take for granted before they begin their >> experiments is infinitely more interesting than any results to which their >> experiments lead. >> -- Norbert Wiener >> > > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener
