Making FGMRESSolver accept nothing as the right preconditioner

[shreyas02]

I am working on a project where I only want to use the left preconditioner using the FGMRES solver. I want this solver to accept nothing as the input for the right preconditioner. Can I create a pull request with these changes?

[JordiManyer]

Hi @shreyas02 , I believe FGMRES is not flexible wrt the left preconditioner. I follow the article from Saad, but if you look around (for instance PETSc) you will see no-one has a left-preconditioned FGMRES.

At least that is my understanding. Can you provide any reference implementing/showcasing a left-preconditioned flexible FGMRES? If you do, I'll be glad to accept your PR.

Alternatively, you can use GMRES with only a left-preconditioner. But the preconditioner needs to be static.
Let me know what you think.

[shreyas02]

Hi @JordiManyer, You seem to be correct. I should be using the GMRES solver, at least for now. Thank you!

[JordiManyer]

@shreyas02 No worries! Thanks for using the library, and for being willing to contribute!