[petsc-users] gamg out of memory with gpu

[Matthew Knepley]

On Mon, Dec 26, 2022 at 10:29 AM Edoardo Centofanti <
edoardo.centofanti01 at universitadipavia.it> wrote:

> Thank you for your answer. Can you provide me the full path of the example
> you have in mind? The one I found does not seem to exploit the algebraic
> multigrid, but just the geometric one.
>

cd $PETSC_DIR/src/snes/tutorials/ex5
./ex5 -da_grid_x 64 -da_grid_y 64 -mms 3 -pc_type gang

and for GPUs I think you need the options to move things over

  -dm_vec_type cuda -dm_mat_type aijcusparse

  Thanks,

     Matt


> Thanks,
> Edoardo
>
> Il giorno lun 26 dic 2022 alle ore 15:39 Matthew Knepley <
> knepley at gmail.com> ha scritto:
>
>> On Mon, Dec 26, 2022 at 4:41 AM Edoardo Centofanti <
>> edoardo.centofanti01 at universitadipavia.it> wrote:
>>
>>> Hi PETSc Users,
>>>
>>> I am experimenting some issues with the GAMG precondtioner when used
>>> with GPU.
>>> In particular, it seems to go out of memory very easily (around 5000
>>> dofs are enough to make it throw the "[0]PETSC ERROR: cuda error 2
>>> (cudaErrorMemoryAllocation) : out of memory" error).
>>> I have these issues both with single and multiple GPUs (on the same or
>>> on different nodes). The exact same problems work like a charm with HYPRE
>>> BoomerAMG on GPUs.
>>> With both preconditioners I exploit the device acceleration by giving
>>> the usual command line options "-dm_vec_type cuda" and "-dm_mat_type
>>> aijcusparse" (I am working with structured meshes). My PETSc version is
>>> 3.17.
>>>
>>> Is this a known issue of the GAMG preconditioner?
>>>
>>
>> No. Can you get it to do this with a PETSc example? Say SNES ex5?
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> Thank you in advance,
>>> Edoardo
>>>
>>
>>
>> --
>> 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/>
>>
>

-- 
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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