On Friday, July 13, 2012 21:51:40 Bart Janssens wrote: > Hi guys, > > I've been thinking about a feature for our DSEL, where lots of matrix > products can occur in an expression. Part of an expression might be: > nu_eff * transpose(nabla(u)) * nabla(u) + transpose(N(u) + > coeffs.tau_su*u_adv*nabla(u)) * u_adv*nabla(u) > > Here, u_adv*nabla(u) is a vector-matrix product that occurs twice, so > it would be beneficial to calculate it only once. I was wondering if > it would be doable to construct a fusion map, with as keys the type of > each product occurring in an expression, and evaluate each member of > the map before evaluating the actual expression. When the expression > is evaluated, matrix products would then be looked up in the map. > > Does this sound like something that's doable? I'm assuming the fold > transform can help me in the construction of the fusion map. Note also > that each matrix has a compile-time size, so any stored temporary > would need to have its type computed.
In a way, this reminds me of how local variables in phoenix work. You have the key (the variables name) which is a distinct type, and you look up the value of that key in a fusion map. The only real difference is that local variables aren't computed lazily, but that should be a nobrainer to add. Might get interesting in a multi-threaded environment though. > > Cheers, _______________________________________________ proto mailing list proto@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/proto
