If you have a stored matrix (strongly discouraged as a workflow, but handy for tests), you can run ksp/ksp/examples/tutorials/ex10.c (no need to edit code). If you have a structured grid and want a fast solver, you should consider using geometric multigrid; see src/ksp/ksp/examples/tutorials/ex22f.F90 which has that capability.
SONG Pengyang <peter...@outlook.com> writes: > Hi all, > I am a new user of PETSC, and I am trying to use KSP to solve a 3D Poisson > problem. The 3D Poisson problem is differenced by myself, which means that > matrix A is given already. > I have found several examples in KSP tutorials but I want to know which one > is suitable for me in “ex2f; ex6f; ex15f; ex21f; ex44f; ex45f” > Thanks in advance. > Regards, > Pengyang > > ---------------------------------------------------------------- > Pengyang Song(宋朋洋) > MSc candidate in Physical Oceanography > College of Oceanic and Atmospheric Sciences > Ocean University of China > No. 238 Songling Road, Qingdao 266100, Shandong, China > TEL: (+86) 15762264643