> If I understand you correctly, a trick we use for this is to use > MatGetRow to get the sparcity pattern of each row (where you are > applying BCs)
Neat trick. MatGetRow will give me the row of the matrix, so would then need a little loop to examine the elements and proceed as you suggested; am I right? I guess there is no way to directly access the sparsity pattern then? Thanks for the suggestion. 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