I am curious. I have and still do often invert the preconditioner to get a good enough guess to start my iterations. Typically, it yields a faster convergence especially inside a nonlinear scheme (newton/picard).
Sure, for nonlinear problems this is well known.
I've never really needed this for just linear systems so far but would've thought that with a good guess, the iteration count should drop.
But for this one, I think yes it sounds like it should be a good idea but it turns out to make little difference in practice.
W. -- ------------------------------------------------------------------------ Wolfgang Bangerth email: [email protected] www: http://www.math.tamu.edu/~bangerth/ _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
