[petsc-dev] TS Terminology

[Jed Brown]

Emil Constantinescu <emconsta at mcs.anl.gov> writes:

> Matt, that depends, if TS method is imex, 

Nothing to do with "TS method".  The "imex" parameter is an argument to
the function TSComputeIFunction.  SNESComputeFunction's behavior depends
on whether snes->vec_rhs exists, but TSComputeIFunction's behavior
depends only on the arguments that are passed.

> then it computes just F, not F-G so your argument is not correct. If
> the method can do only implicit it computes F and subtracts G *if
> defined*. If the TS method can only do explicit and you define F then
> it fails.
>
> Again, this has to do with the TS methods and PETSc doing the work for 
> you of packing the functions in different ways.