On Nov 1, 2007, at 4:17 PM, Berend van Wachem wrote: > Hi Barry, > > >> Perhaps you could describe how your matrix entries are generated >> and we can suggest a >> preallocation scheme? > > Are there examples of preallocation schemes for PETSc? For instance, > if I would like to solve Poisson equation on an irregular grid (9 > point stencil in 2d and 27 in 3d) on n processors?
This would depend on how you store your grid information; is it treated as unstructured? For structured or semi-structured take a look at DAGetMatrix2d_MPIAIJ() in src/dm/da/utils/fdda.c Barry > > > Thanks, > Berend. >
