Hi! I have some questions about TS functions. 1. I tried to use TSDefaultComputeJacobian to provide the Jacobian matrix. It worked fine with TS_BEULER, but when I tried to use TS_CN, it didn't work. The error message indicates that it is not supported for Crank-Nicholson. Is it true or I might do something wrong? 2. Is there a specific PETSc function to evaluate Jacobian for TS_CN? Any example of using TS_CN that I can refer to? 3. I tried to solve a simple time evolving diffusion problem with TS, using TS_BEULER and non-linear solver. When I tried to use big time step, sever over-prediction is observed. I would appreciate any suggestion on the criteria of maximum time step allowed. If I really need to use big time steps, any tips to set up TS to improve the results?
Many thanks in advance! BJ _________________________________________________________________ ?????????????????????????? http://im.live.cn/Share/18.htm -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20080909/6edd5424/attachment.htm>
