[petsc-users] TSSetMatrices structure?

[Andrew Spott]

In the Petsc manual, there is a TSSetMatrices function, however there is no further documentation for it.

It is referenced in the manual as:

TSSetMatrices(TS ts,
Mat A,PetscErrorCode (*frhs)(TS,PetscReal,Mat*,Mat*,MatStructure*,void*), Mat B,PetscErrorCode (*flhs)(TS,PetscReal,Mat*,Mat*,MatStructure*,void*), MatStructure flag,void *ctx)

However, what is passed to the function pointers isn't mentioned anywhere, and it isn't in the online documentation.

Also, I assume that "MatStructure flag" tells if the structure of A and B are the same or different, if B is PETSC_NULL, is flag "SAME_NONZERO_PATERN" or is it different?  (B can be considered to not exist, or to exist as an identity matrix, hence the confusion).

How does the ctx work?  Is the same context passed to frhs each time?

Thanks for the help.

-Andrew