How do we populate problem_data?

[Aron Ahmadia]

All, 

I know that we are still thinking about the Riemann functionality, and whether it makes sense to move to heavier Fortran-90 modules or leave them as light-weight functions.  This is a separate issue with regards to how we compose the problem_data object, especially when restarting/continuing an earlier run, as Amal points out in a recent issue.

being discussed on github.  I'm linking directly to my summary of the issue here: https://github.com/clawpack/pyclaw/issues/236#issuecomment-14682070

I don't have a lot of experience with how problem_data is used/generated, so I'm interested in hearing what others have to say before we decide what to do.

Cheers,

Aron