Xiaoyin: > > I was wondering if petsc could convert an existing matrix into a > preconditioner and use it in ksp solvers...thought this shall be a > straight-forward question but I didn't find the answer in manuals. Thanks a > lot.
Yes, you can. See "Shell Preconditioners" in petsc user manual. Also, check out ~petsc/src/ksp/ksp/examples/tutorials/ex15.c as an example. Hong
