[petsc-users] Possible bug PETSc+Complex+CUDA

[Mills, Richard Tran]

Yes, Junchao said he gets the segfault, but it works for Karl. Sounds like this may be a case of one compiler liking the definitions for complex that Thrust uses, and some not, as Stefano says. Karl and Junchao, can you please share the version of the compilers (and maybe associated settings) that you are using?

--Richard

On 5/21/20 9:15 AM, Junchao Zhang wrote:
I tested this example with cuda 10.2, it did segfault. I'm looking into it.
--Junchao Zhang


On Thu, May 21, 2020 at 11:04 AM Matthew Knepley <knepley at gmail.com<mailto:knepley at gmail.com>> wrote:
On Thu, May 21, 2020 at 11:31 AM Stefano Zampini <stefano.zampini at gmail.com<mailto:stefano.zampini at gmail.com>> wrote:
Oh, there is also an issue I have recently noticed and did not have yet the time to fix it

With complex numbers, we use the definitions for complexes from thrust and this does not seem to be always compatible to whatever the C compiler uses
Matt, take a look at petscsytypes.h and you will see the issue https://gitlab.com/petsc/petsc/-/blob/master/include/petscsystypes.h#L208

For sure, you need to configure petsc with --with-clanguage=cxx, but even that does not to seem make it work on a CUDA box I have recently tried out (CUDA 10.1)
I believe the issue arise even if you call VecSet(v,0) on a VECCUDA

So Karl and Junchao say that with 10.2 it is working. Do you have access to 10.2?

  Thanks,

     Matt

On May 21, 2020, at 6:21 PM, Matthew Knepley <knepley at gmail.com<mailto:knepley at gmail.com>> wrote:

On Thu, May 21, 2020 at 10:53 AM Rui Silva <rui.silva at uam.es<mailto:rui.silva at uam.es>> wrote:
Hello everyone,

I am trying to run PETSc (with complex numbers in the GPU). When I call
the VecWAXPY routine using the complex version of PETSc and mpicuda
vectors, the program fails with a segmentation fault. This problem does
not appear, if I run the complex version with mpi vectors or with the
real version using mpicuda vectors. Is there any problem using
CUDA+complex PETSc?

Furthermore, I use the -log_view option to run the complex+gpu code,
otherwise the program fails at the beggining.

What version of CUDA do you have? There are bugs in the versions before 10.2.

  Thanks,

    Matt

Best regards,

Rui Silva

--
  Dr. Rui Emanuel Ferreira da Silva
  Departamento de Física Teórica de la Materia Condensada
  Universidad Autónoma de Madrid, Spain
  https://ruiefdasilva.wixsite.com/ruiefdasilva
  https://mmuscles.eu/



--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
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--
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

https://www.cse.buffalo.edu/~knepley/<http://www.cse.buffalo.edu/~knepley/>

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