2011/3/30 Gong Ding <gdiso at ustc.edu> > I know the bad condition number comes from a lumped boundary. > For this boundary, the sum of flux comes from all the boundary elements > shoule equals to a fixed given flux. >
Sounds like your problem has a one dimensional null space, have you tried setting the null space? (See the user's manual section on solving singular systems or docs for KSPSetNullSpace().) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110331/89e242ab/attachment.htm>
