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

[Robert Annewandter]

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! Thank you! Robert