On Tue, Feb 28, 2012 at 14:20, Dmitry Karpeev <karpeev at mcs.anl.gov> wrote:
> Just out of curiosity: how many transient problems have we seen where the > transient residual doesn't split like R(U,U_t) = R_0(U_t) + R_1(U)? There > is the issue of explicit dependence on time, but if that could be > addressed, the problem would naturally split and, as a side benefit, there > would be a natural "mass" matrix coming out of the linearization of R_0. > Moving mesh problems often have terms involving both U_t and U. The IMEX interface is g(t,X,X_t) = f(t,X) which lets us split the implicit and explicit parts. Having a separate mass matrix is normally quite wasteful and it's confusing for people doing matrix-free methods where it is natural to keep both together. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120228/2d18ec2d/attachment.html>
