Hello guys, Today I am about to write a custom convergence test for KSP doing the following job:
- if the number of ksp iterations is less than a given threshold, iterate until that threshold is met - if the number of ksp iterations is bigger than the threshold, use the standard convergence checks. As far as I understood from the examples, this is the function I need to use: KSPSetConvergenceTest <https://petsc.org/main/manualpages/KSP/KSPSetConvergenceTest/>(ksp,MyKSPConverged,0,PETSC_NULL_FUNCTION,ierr) With MyKSPConverge a subroutine (I am in fortran) where my custom checks are implemented. Here is how I have coded MyKSPConverged: * subroutine MyKSPConverged(ksp,n,rnorm,flag,dummy,ierr) KSP ksp PetscErrorCode ierr PetscInt n,dummy KSPConvergedReason flag PetscReal rnorm if (n>1) then call KSPConvergedDefault(ksp, n, rnorm, flag, ierr) else flag = 0 endif ierr = 0 end subroutine MyKSPConverged* However I get this error: [0]PETSC ERROR: KSPSolve has not converged, reason DIVERGED_DTOL which I believe to be triggered by *KSPConvergedDefault. *This is odd, as this simulation converge perfectly if I comment ou my dodgy convergence test. *Do you have any advice for me?* *thank you! *