On Thu, Jun 16, 2011 at 17:57, Matthew Knepley <knepley at gmail.com> wrote: > > > Doesn't he need A' A (normal equations) >
Note that A has many more columns than rows, therefore A'*A has huge null space. > for the solve, so a MatShell? > I'm sorry, yes. Or MatComposite: http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-dev/docs/manualpages/Mat/MatCreateComposite.html But there is also likely some regularization so MatShell makes sense. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110616/8e379643/attachment.htm>
