SNES Problem

[Matthew Knepley]

On 3/29/06, Nils Erik Svangård <nilserik at gmail.com> wrote:
>
> Barry,
> You wrote this a couple of mails back:
>
>   SNES works by computing p = -approxinv(J)*F(uold) and
> then does a line search on unew = uold + lambda*p to get the
> new u. First it uses a test value of 1 for lambda so it
> tries to compute F(uold + p). It is possible that uold + p
> has some "non-physical" values in it.
>
> Does SNES do the same thing when -snes_mf is used?


  Yes, the line search is independent of the Jacobian approximation.

    Matt

/nisse
>
> On 3/20/06, Barry Smith <bsmith at mcs.anl.gov> wrote:
> >
> >    Nisse,
> >
> >     Is there any way you can bundle everything up so you could send
> > it to me and I could easily compile it and make? This approach to
> > trying to discover the problem is taking too long.
> >
> >     Barry
>

--
"Failure has a thousand explanations. Success doesn't need one" -- Sir Alec
Guiness
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20060329/bee1058a/attachment.htm>