Dear users, I have a problem where I step time and repeatedly solve a system with differing rhs. At some time step petsc solver returns that initial solution is good enough (converged reason = 2 with 0 iterations done). I do not expect this behaviour. I use rtol = 0.001, atol=0 and dtol =large number.
The manual seems to suggest the criterion is: rnorm < MAX (rtol * rnorm_0, abstol) (probably based on preconditioned residual). How could this lead to zero iterations being done? Or is the criterion based on rnorm/bnorm instead (which I found in some reference on the internet concerning petsc and would explain the observed behaviour). Thanks, Danny.
