Is there any general rule of thumb that dictates when to use a full

matrix over a sparse matrix? any specific matrix density ?

Does matlab run much slower if store and operate on relatively dense

matrices as a sparse matrix?

Basically, I'm working with a matrix that is about 1/4 full. But all

the operators are one or a few times more dense than a diagonal

matrix. So I'm guessing that I should store the operators as sparse

matrices and have them operate on a full matrix. The matrix

dimensions are on the order of around 1000's x 1000's.