[petsc-dev] Additive Schwarz Method + ILU on GPU platforms

[Junchao Zhang]

Petsc supports ILU0/ICC0 numeric factorization (without reordering) and
then triangular solve on GPUs. It is done by calling vendor libraries (ex.
cusparse).
We have options -pc_factor_mat_factor_on_host <bool>
-pc_factor_mat_solve_on_host <bool> to force doing the factorization and
MatSolve on the host for device matrix types.

You can try to see if it works for your case.

--Junchao Zhang


On Mon, Apr 14, 2025 at 4:39 PM Angus, Justin Ray via petsc-dev <
petsc-dev at mcs.anl.gov> wrote:

> Hello,
>
>
>
> A project I work on uses GMRES via PETSc. In particular, we have had good
> successes using the Additive Schwarz Method + ILU preconditioner setup
> using a CPU-based code. I found online where it is stated that “Parts of
> most preconditioners run directly on the GPU” (
> https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!eyXTlwwR7hk0RuEHQeXwSjtY-JDprhL8r0c2jgb_kBbJWzN8qkstC-zZhjwPAO_p1MjiVAFFHjIFiA1HWp2uDuxVekdn$ 
> <https://urldefense.us/v3/__https://petsc.org/release/faq/__;!!G_uCfscf7eWS!bw6qeKcY7MKSvlEgcogdKR7fpjZSOFvka6zfDprUZ_sJHdE-YZmRD6UTqWQW3_uGVBII4P-AG0zaGTLbI67_fQ$>).
> Is ASM + ILU also available for GPU platforms?
>
>
>
> -Justin
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20250414/6062755b/attachment.html>