[Boost-users] Matrix of submatricies...

Dear all, [you may need a fixed with font] Consider the following 4x4 matrix which is a 2x2 matrix of submatricies. A B | 0 0 C D | 0 0 ----+---- 0 0 | a b 0 0 | c d Clearly matrix operations such as products do not need to involve the off diagonal (zero) sub matricies. Is there a matrix type that "knows" about this type of matrix so that when prod() is carried out it does not do unnecessary operations with the zero elements? -ed