[petsc-users] Control Output of '-ksp_view_mat binary'

[Barry Smith]

   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 <knepley at gmail.com> wrote:
> 
> On Thu, Nov 17, 2016 at 8:32 AM, Robert Annewandter <robert.annewandter at opengosim.com> 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