Just a note, my way is much simpler - its two lines of code in a loop over the boundary nodes, followed by an MatAsseblyBegin/End, and you don't have to deal with parallel issues explicitly - PETSc does. For my FE codes the cost of this (dumb) way is negligible, PETSc implements these methods pretty well.
Mark On Jun 15, 2007, at 4:28 PM, Toby Young wrote: > > > Barry, > > Thank you for an interesting response. > >> For algorithms that require dealing with the sparsity structure of >> the matrix we generally just include the appropriate private >> include file >> for the matrix format and access the data directly in the >> underlying format. > > Can you please elaborate. What do you mean by "the appropriate privat > include file for the matrix"? Sorry, I got lost there. > > Best, > Toby > > ----- > > Toby D. Young (Adiunkt) > Department of Computational Science > Institute of Fundamental Technological Research > Polish Academy of Science > Room 206, ul. Swietokrzyska 21 > 00-049 Warszawa, POLAND > ********************************************************************** Mark Adams Ph.D. Columbia University 289 Engineering Terrace MC 4701 New York NY 10027 adams at pppl.gov www.columbia.edu/~ma2325 voice: 212.854.4485 fax: 212.854.8257 **********************************************************************
