On Wed, Aug 24, 2011 at 14:11, Likun Tan <likunt at andrew.cmu.edu> wrote:
> I am solving a linear equation Ax=0 with Petsc. > Previously i was following Numerical Recipe and using LU decomposition, > for a non-singular matrix A, x should be zero. By applying LU in Recipe, i > got x=0. > When i solve it with ksp, x is some small value to the power of -9. > This is normal. You can make it more accurate by reducing the tolerance, e.g. -ksp_rtol 1e-12. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110824/44180da7/attachment.htm>
