[vtkusers] vtkXMLPUnstructuredGridWriter() howto?

[Sebastien Jourdain]

ParaView will exactly do that, but on the VTK+MPI side, I don't know
exactly what you should do to make it works. I guess it's all about
setting correctly vtkMultiProcessCommunicator... The number of Piece
should normally be equal to the number of processes, and this might be
automatic in some way. Give a look at the test/examples files of
Parallel VTK kit.

Seb

On Fri, Aug 27, 2010 at 12:22 AM, Nico Schlömer
<nico.schloemer at gmail.com> wrote:
>> PxReader to directly read each file on a given process with MPI so
>> your data are already partitioned.
>
> Oh, and how about you work with this data on N processes, and then
> want to write it to a file without having to transfer all the data to
> one core? I thought that was the general idea: One file per process,
> in/out.
> My situation is exactly like that: I've got this huge std::vector the
> entries of which are distributed over the N processes, and like to do
> some I/O with it.
>
> Cheers,
> Nico
>
>
>
> On Thu, Aug 26, 2010 at 11:10 PM, Sebastien Jourdain
> <sebastien.jourdain at kitware.com> wrote:
>> I didn't use any writer recently, but PxWriter usually write 1 file
>> per piece and a master file somehow. So you can later on, use a
>> PxReader to directly read each file on a given process with MPI so
>> your data are already partitioned.
>>
>> Seb
>>
>> On Thu, Aug 26, 2010 at 11:04 PM, David Doria <daviddoria+vtk at gmail.com> wrote:
>>> On Thu, Aug 26, 2010 at 10:52 PM, Sebastien Jourdain
>>> <sebastien.jourdain at kitware.com> wrote:
>>>>
>>>> I think you just need a vtkUnstructuredGrid and set it to the input of
>>>> the writer. Specify the number of pieces you want and call Update() on
>>>> the writer.
>>>>
>>>> Seb
>>>
>>>
>>> There was a question about SetNumberOfPieces the other day that never got
>>> resolved - Sebastien, could you take a
>>> look: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Broken/IO/XMLPImageDataWriter
>>> Nico, once we get this issue resolved I'll make the same type of example
>>> for vtkXMLPUnstructuredGridWriter.
>>> Someone please correct me if I'm wrong, but these P*Writer's don't write in
>>> parallel, they simple write data as multiple files (pieces) that can later
>>> be used for parallel processing.
>>> David
>>
>