[petsc-dev] changes to the TS structure

[Jed Brown]

On Tue, 18 May 2010 14:51:57 -0300, Lisandro Dalcin <dalcinl at gmail.com> wrote:
> 1) Could we remove "vec_sol_always" from the TS structure?

Maybe, but are we really getting rid of vec_sol_always or just renaming
it to vec_sol and being careful not to update vec_sol until after the
step has been accepted?  The first doesn't work because you lose the
ability to reject a step, the latter is fine, but it means that the
method always needs to make private vectors to hold the solution while
solving the stages.

> 2) For the case of nonlinear problems, could we have a new "vec_res",
> then update Theta and GL to use it?

Is there a reason that SNES can't own the residual?  Is it indeed the
case that it will only be updated by SNESTSFormFunction?

Jed