Multiple resets on Preconditioner's Operator per SNES iteration

[okrzysik]

Hi,

In every SNES iteration the following two functions are called once each: 1. PetscSNESSolver::setJacobian(), and 2. PetscSNESSolver::setupPreconditioner().

1. PetscSNESSolver::setJacobian() does a resetOperator() on SNES's PetscKrylovSolver. If this PetscKrylovSolver has a preconditioner with an Operator, then this resetOperator() triggers a resetOperator() on the preconditioner's Operator.
2. PetscSNESSolver::setupPreconditioner() explicitly does a reset on the preconditioner's Operator. It then does a reset of the preconditioner with null parameters (which may or may not trigger a further reset of its operator; the reset() in the base class SolverStrategy includes a reset of its Operator)

Thanks,
Oliver