On 21. okt. 2013 14:42, Jed Brown wrote: > > The coordinates live in a different space than the DM. Why is it > illogical to use the coordinate DM to access coordinate vectors? It is > used in several examples, though none of them in Fortran. >
I guess it is logical for e.g. unstructured meshes or finite elements, but for someone like me who just wants 2/4/9 real numbers, it seems a bit overkill to have another DM. > > "van der Pol" normally refers to a 2-variable ODE system (e.g., > src/ts/examples/tutorials/ex16.c). I assume you are talking about a > PDE, however. I am actually talking about that 2-variable ODE. We use it as a test problem in several of our codes, since it is stiff and has some "structure", but is much simpler than Euler or Navier-Stokes. In my example I "distribute" it so that we solve the same equation at all grid points on all processors, using the same code as a PDE solver but with a different RHS. I don't know whether the pattern we use is common or not, so I'll submit a pull request and then you can see if you think this is useful for others. Another option would be an example solving full-blown Navier-Stokes (single phase), but that would take some more work, and I don't know when I'll have time for that. Åsmund
