Right-preconditioned PETScKrylovSolver twice as expensive with monitor

[Jan Blechta]

In PETScKrylovSolver there is KSPMonitorTrueResidualNorm which causes with right preconditioning that preconditioner is applied twice as many while this is completely useless considering that true and "preconditioned" norms are the same for right preconditioning.

This could be considered as a bug in PETSc and filed there.

The workaround is simple. Do not use solver.monitor(true) or solver.parameters["monitor_convergence"] = true but call rather PETScOptions::set(solver.get_options_prefix()+"ksp_monitor") and solver.set_from_options().

[Prof Garth Wells]

Using solver.monitor(true), etc also leaks memory.