[petsc-users] one question about GPU

[Yujie]

Dear PETSc Developers,

I just took a look at new faq and got the following information,

"Can PETSc use GPUs to speedup computations?

PETSc-dev has some support for running portions of the computation on
Nvidia GPUs. See installation.html for how to install PETSc to use
GPUs. PETSc has a Vec class VECCUDA that performs almost all the
vector operations on the GPU. The Mat class MATCUDA performs
matrix-vector products on the GPU but does not have matrix assembly on
the GPU yet. Both of these classes run in parallel with MPI. All KPS
methods, except KSPIBCGS, run all their vector operations on the GPU
thus, for example Jacobi preconditioned Krylov methods run completely
on the GPU. Preconditioners are a problem, we could do with some help
for these. The example src/snes/examples/tutorials/ex47cu.cu
demonstates how the  nonlinear function evaluation can be done on the
GPU."

I have also checked the codes of PETSc. I found the codes relevant to
GPU are added in "SEQ" not "MPI". Also, only few functions are
realized currently for Vec and Mat. However, from FAQ, "Both of these
classes run in parallel with MPI". How to realized it regarding
current version? Thanks a lot.

Regards,
Yujie