Rutger ter Borg wrote:
Maybe if you're able to "add" type-tags to a matrix_expression or something like that? Sorry to keep using the solve example, but say you would have symmetric matrix A,
x = solve( A, b ) x = solve( positive_definite( A ), b )
then both expressions in the first argument are matrices, but the second could be identified, e.g., by a meta-function
is_positive_definite< expr >
which evaluates to a true_type?
Yes. I'll have to find the proper way to add tags in the proto expression I build. If all get worse, I can store a mpl::set of tags in the expression types then have a proto transform that iterate over expression to retrieve the first set tags it founds. This makes solid sense. -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35