On Oct 21, 2010, at 5:56 PM, Matthew Knepley wrote: > On Thu, Oct 21, 2010 at 4:46 PM, Xuan Yu <xxy113 at psu.edu> wrote: > Hi > > > I am using Petsc solve ODE nonlinear problem. > > I was told to use direct method: umfpackage because of the jacobian matrix is > 1860 by 1860. > > But the time consumption is still too big: > > TSSetType(ts,TSBEULER) > > time ./pihm -log_summary -ksp_type preonly -pc_type lu > -pc_factor_mat_solver_package umfpack > > I got the result: > > > When I use TSSetType(ts,TSSUNDIALS), it is fast: > > > > How can I find the reason why BEULER is so slow? > > You SNES is not converging. You solve 163 systems, but do 4300 function > evaluations.
Could you please tell me more solution options or possible mistakes in my code? > > Matt > > Thanks > > Xuan > > > > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20101021/a02249ad/attachment.htm>
