> Hi Matt,
>
> As current petsc-gpu implementation have support only for CSR, If I want to
> take advantage of other matrix formats, say ELL on GPU, how can I achieve
> this? Adding implementation for new format similar to current CSR
> implementation?

 First hunt up what formats people have done in CUSP/THRUST or CUDA and see what source code is available. Then you can simply write a "wrapper" that takes a PETSc CPU matrix (for example in CSR) and converts it as it puts it onto the GPU to whatever that "better" format is.

>
> Is someone currently working on development in this area or in area of
> petsc-gpu?

  We do not have anyone working on other matrix formats for GPUs. You can join the petsc-dev@mcs.anl.gov mailing list and tell us your experience. The key point is you only need to muck with a relatively small amount of code to have PETSc use a different GPU solver; but you will need to understand that code pretty well.

  Barry