[petsc-users] Nonlinear solver for non-smooth jacobian

[Jed Brown]

Que Cat <quecat001 at gmail.com> writes:

> Hello Petsc-users,
>
> I have to solve a problem in which the jacobian is non-smooth ( incoporates
> the heaviside step function behavior from the derivative of F(x) ). Could
> you recommend any type of nonlinear solver in Petsc which handles this
> issue ?

You can reformulate as a variational inequality and use SNESVI.  Be
warned that it's not for the faint of heart and it's less mature than
the "smooth" solvers.

If this nonsmoothness is absolutely fundamental to your physics, like
contact or condensation, then you should expect to invest significant
effort in finding the best formulation.  If the nonsmoothness is not
essential, you should put that effort into reformulating to avoid or
lessen the nonsmoothness.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 818 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20141020/5616da22/attachment.pgp>