[petsc-users] Assembling MatSeqAICUSPARSE from kernel

[Mark Adams]

Hector,
It is pretty simple and a bit cumbersome, but see src/mat/tutorials/ex5cu.cu
for the example.
Mark

On Wed, Sep 30, 2020 at 2:32 PM Héctor Barreiro Cabrera <hecbarcab at gmail.com>
wrote:

> This is awesome news! I will go over it and see how can I fit this with my
> code.
>
> Thank you!
>
> El mié., 30 sept. 2020 17:55, Barry Smith <bsmith at petsc.dev> escribió:
>
>>
>>   Hector,
>>
>>    You asked at just the right time. Mark Adams has started to implement
>> some code to do this https://gitlab.com/petsc/petsc/-/merge_requests/3137 it
>> is now in the PETSc master branch. It is preliminary and not yet well
>> documented but hopefully if you read through the MR (above) it will give
>> you the main ideas.
>>
>>    Please feel free to ask questions on this topic at GitLab or on
>> petsc-dev at mcs.anl.gov we are eager to have users for this material and
>> improve it to make it practical and straightforward.
>>
>>
>>   Barry
>>
>>
>> On Sep 30, 2020, at 9:49 AM, Héctor Barreiro Cabrera <hecbarcab at gmail.com>
>> wrote:
>>
>> Greetings fellow PETSc users!
>>
>> I have recently started working on a project that requires assembling and
>> solving a large sparse linear system directly on the GPU using CUDA. I have
>> just discovered that PETSc has support for building and solving such a
>> system through cuSparse (MatSeqAICUSPARSE), which is quite cool because
>> this opens up the possibility of using PETSc's awesome functionalities.
>>
>> However, I have not been able to find information about how (or even if
>> it is possible) to assemble the matrix from data stored in device memory.
>> From the documentation, it seems that vectors (VecSeqCUDA) expose the raw
>> device pointer through VecCUDAGetArrayRead and VecCUDAGetArrayWrite
>> functions which I could use to update the systems' RHS vector, but I
>> couldn't find anything alike for matrices. Is there anything equivalent?
>>
>> Ideally I would like to generate all the assembly information from a
>> kernel, avoiding any data synchronization with the host (except maybe
>> updating the pointers). Is this even possible?
>>
>> Thank you very much for your help!
>>
>> Greetings,
>> Hector Barreiro
>>
>>
>>
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