Simon, There is not because what does MatSet() mean for a sparse matrix? Make it dense, just set all the current nonzeros, error? You tell us, I could live with either of the later two but don't really like the first. Barry BTW: possibly related note, are you using dense matrices sometimes to represent "just" 2-arrays; that is, not as representations of linear operators. If so, I do not think this is the correct approach! Conceptually PETSc Mat's are linear operators I think it would be a big mistake to overload them as 2-arrays also. The "correct" approach is to use the DACreate2d() construct for handling 2-d arrays; With the DA the values are stored into Vecs but there is additional information about the two array structure; it can be decomposed nicely in parallel and one can set/access values with the usual two i,j indices. Of course if they are being used as operators ignore this. In Matlab matrix == 2-d array == matrix (in my opinion a terrible design decision) in PETSc matrix (dense) != 2-d array , the are completely different beasts mathematically On Fri, 19 Aug 2005, Simon Burton wrote:

Is there a way to simulate a MatSet (like VecSet) ?

Simon.