You can also call MatView(jac,PETSC_VIEWER_BINARY_WORLD); at the location where you compute the Jacobian based on the iteration number etc
> On Nov 17, 2016, at 9:35 AM, Matthew Knepley <[email protected]> wrote: > > On Thu, Nov 17, 2016 at 8:32 AM, Robert Annewandter > <[email protected]> wrote: > Hi, > > Is there a way to fine tune '-ksp_view_mat binary' so it only gives me an > output at a defined time? > > I'm implementing a Two-Stage Preconditioner for PFLOTRAN (a subsurface flow > and transport simulator which uses PETsc). Currently I like to compare > convergence of the preconditioning in PFLOTRAN against a prototyped version > in MATLAB. In PFLOTRAN I export the Jacobian, and residual before they get > handed-over to PETsc, which get imported in MATLAB to do the Two-Stage > Preconditioning. > > However, I know I can do exports closer to PETsc with the options > '-ksp_view_mat binary' and '-ksp_view_rhs binary'. Unfortunately I get > outputs for the whole simulation in one file, instead of only at a > well-defined Newton-Raphson iteration (as done in PFLOTRAN). > > Is there a way to tell PETsc with above options when to export the Jacobian > and residual? > > Any pointers much appreciated! > > It sounds like you could give the particular solve you want to look at a > prefix: > > > http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/KSPSetOptionsPrefix.html > > and then give > > -myprefix_ksp_view_mat binary > > Thanks, > > Matt > > Thank you! > Robert > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener
