On Mar 4, 2013, at 10:43 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> > On Mon, Mar 4, 2013 at 10:36 AM, Barry Smith <bsmith at mcs.anl.gov> wrote: > So you save the solution at some time step. Then later in another part of the > calculation, you time integrate the solution for a few time steps (from the > saved time-step) to "fill in" the solution values you did not save, then you > use the solutions for those several time steps, then you discard them. > > So the question has nothing to do with SNES. It has to do with a "deep > copy" of TS? Or being able to "restart" TS at a saved time step? Capabilities > we want to build towards, but thinking in terms of a deep copy of SNES is a > red herring. > > Indeed, but presumably Johannes is working with an application that uses SNES. Why would he be doing that? Surely it is better to use a TS integrator in PETSc rather than to roll your own? If we were missing a feature needed for his integrator from TS then we would gladly add it. Barry > > > So, assuming one is using a single time integrator (not changing the > integration method for different times), shouldn't this already pretty much > work? > > Yes, that's why I asked what sort of changes he was trying to guard against. > Saving an entire copy of the SNES for each problem is wasteful when by far > the most common case is to reuse configuration in each solve.
