typedef enum {
PCRICHARDSON_CONVERGED_RTOL = 2,
PCRICHARDSON_CONVERGED_ATOL = 3,
PCRICHARDSON_CONVERGED_ITS = 4,
PCRICHARDSON_DIVERGED_DTOL = -4} PCRichardsonConvergedReason;
Notes: this must match petsc/finclude/petscpc.h and the KSPConvergedReason values in petscksp.h