Barry, thanks you for your help. Is there a database options that allows me to check weather PC has been recomputed or kept the same?
Thanks, Michele On Thu, 2015-07-09 at 14:43 -0500, Barry Smith wrote: > By default in the last two PETSc releases KSP automatically updates the > preconditioner whenever the matrix you set with KSPSetOperators() has been > changed. That is you have to do nothing and PETSc will recompute the > preconditioner as needed. If you wish to keep the same preconditioner even > though the matrix has changed then you can use > KSPSetReusePreconditioner(ksp,PETSC_TRUE) and it will keep using the same > preconditioner until you call KSPSetReusePreconditioner(ksp,PETSC_FALSE) > which will switch back to the default mode. > > You only need to destroy the KSP or call KSPReset() when you change the > size of the vectors or matrices. > > Barry > > > On Jul 9, 2015, at 12:20 PM, Michele Rosso <mro...@uci.edu> wrote: > > > > Hi, > > > > I need to recompute the preconditioner every once in a while. So far I do > > this "manually", i.e. I destroy ksp and re-create and reset it whenever > > needed. > > I am wondering if there is a cleaner way of doing this via a PETSc > > function. I found KSPreset but there are no examples about it so I am not > > sure it is what I am looking for. > > Could you help please? > > > > > > Thanks, > > Michele >
