#include "petscksp.h" PetscErrorCode KSPGetResidualHistory(KSP ksp,PetscReal *a,PetscInt *na)Not Collective
|a||- pointer to array to hold history (or NULL)|
|na||- number of used entries in a (or NULL)|
The Fortran version of this routine has a calling sequence
call KSPGetResidualHistory(KSP ksp, integer na, integer ierr)note that you have passed a Fortran array into KSPSetResidualHistory() and you need to access the residual values from this Fortran array you provided. Only the na (number of residual norms currently held) is set.