[petsc-users] vtk output ASCII or binary

[Xiangdong]

At this moment, when I write the solutions (two vectors with a few billion
unknowns) to binary vts format, the writing rate is about 100MB/s from proc
0.

Do you think writing the data into pvts format will enhance the
performance? Can I use some PETSc functions to save the local vector as
pvts format and view them as a global vector through paraview/visit?

Thank you.

Xiangdong


On Tue, Mar 4, 2014 at 4:49 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Tue, Mar 4, 2014 at 3:43 PM, Xiangdong <epscodes at gmail.com> 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 <knepley at gmail.com>wrote:
>>
>>> On Tue, Mar 4, 2014 at 12:58 PM, Xiangdong <epscodes at gmail.com> 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 <knepley at gmail.com>wrote:
>>>>
>>>>> On Tue, Mar 4, 2014 at 12:31 PM, Xiangdong <epscodes at gmail.com> 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 <knepley at gmail.com>wrote:
>>>>>>
>>>>>>> On Tue, Mar 4, 2014 at 11:44 AM, Xiangdong <epscodes at gmail.com>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
>
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