[petsc-dev] snes/examples/tutorials/ex27.c

[Barry Smith]

On Nov 15, 2011, at 3:25 PM, Jed Brown wrote:

> http://petsc.cs.iit.edu/petsc/petsc-dev/rev/c3192eb7cd93
> 
> I would rather not delete this example because it is the example code accompanying a paper that I like. I wrote essentially the same thing in ts/examples/tutorials/ex26.c (which uses TSPseudo), but having the simple, executable example that exactly reproduces the figure in the paper is still useful. Using TS is somewhat less clear because you have to look at library code to see the algorithm, but I could also live with simply documenting how to get the same results with ts/.../ex26.c.
> 
> Preference?

   I think it is best if the TS example be cleaned up to do everything the SNES example did and not have both around. People will stumble upon the SNES one and use it as a template for their work when they should use the TS one.

> 
> As a general rule, many elliptic problems arise as the steady state of some dynamical system. If we write the code using the TS interface, then we can always solve the steady problem by taking an infinite step size with nonlinearly implicit Euler. Should we recommend that all such problems be written using the TS interface?

   I would like the TS pseudo time-stepping stuff to actually be a SNES solver. That is SNESType SNESPSEUDOTS or something and not be part of TS. This is controversial hence nothing has been done to make it this way. Some people may argue it is the wrong approach.

   Barry