> Message: 2 > Date: Tue, 24 Aug 2010 10:56:53 -0500 > From: Barry Smith <bsmith at mcs.anl.gov> > Subject: Re: [petsc-dev] Problem with conjugate gradient solver > To: For users of the development version of PETSc > <petsc-dev at mcs.anl.gov>, Victor Eijkhout < > eijkhout at tacc.utexas.edu> > Message-ID: <A4C6A1ED-CDE7-4653-8046-C2797AD5AF31 at mcs.anl.gov> > Content-Type: text/plain; charset="us-ascii" > > > Well you are doing nothing wrong. When I run the code I get the same > results as you. I dump the matrix into Matlab and it has a negative > eigenvalue so the example is wrong. The code is handling it correctly. > > >> eig(full(Mat_0)) > > ans = > > -0.8042 > 0.1716 > 0.6489 > 1.0000 > 1.0000 > 1.0000 > 1.0000 >
So are you saying that trying to solve the system of equations in the example will always result in divergence? I tried the same program with a different system that I know has a solution, and even that diverges. I get a proper solution if I use the default KSP solver. Anush > > I am cc:iing Victor who supposedly wrote the original example. > > Barry > > Attached is the matrix saved with -mat_view_matlab > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20100826/f67ac466/attachment.html>
