Barry, If I use DMMGSetUseGalerkinCoarse, then do I need DMMGSetKsp, and where do you set up the finest level grid matrix and right hand side?
Randy Barry Smith wrote: > Randy, > > Take a look at src/ksp/ksp/examples/tutorials and > DASetCoordinates(). > > You should do it all with a DMMG and then it should be > pretty easy. > > Barry > > Note also: if you do not want to compute coarse matrices > you can use DMMGSetGalerkin() or -dmmg_galerkin and have > PETSc compute them. > > > On Tue, 10 Oct 2006, Randall Mackie wrote: > >> I'm interested in trying to use multi-grid techniques to solve my problem, >> but it's unclear to me how to define the right-hand side and system matrix >> for my case where the grids are not uniform (ie, the grid lengths x,y,z are >> variable, and the grid properties are variable). >> >> Right now I'm solving my equations using a DA. So, on the finest scale I know >> how to compute the RHS and the Jacobian. It's unclear to me how PETSc >> does the multi-gridding, and therefore how I would write my code. >> >> Any pointers would be appreciated. >> >> Thanks, Randy >> >> > -- Randall Mackie GSY-USA, Inc. PMB# 643 2261 Market St., San Francisco, CA 94114-1600 Tel (415) 469-8649 Fax (415) 469-5044 California Registered Geophysicist License No. GP 1034
