If I act upon a polyhedron, the result is computed twice. Why does this happen, how can one avoid this?
Currently, in `Polyhedron_base` (the element class) the method `_acted_upon_` is defined, which is where the action is discovered. In the following example, I try to act on a polyhedron with a matrix. If I first discover the action, I'm much faster than when I just plainly multiply. The reason is that for discovering action manually, the method `an_element` of parent is used. Very smart, because this is an almost trivial element just to make things work. However, if I just plainly multiply, it is not done this way. Instead it computes the result twice. Why? Thank you, Jonathan sage: P = polytopes.permutahedron(6) sage: M = matrix(P.base_ring(), P.dim(), P.ambient_dim(), ....: [v.vector() - P.an_affine_basis()[0].vector() for v in P.an_affine_basis()[1:]]) sage: %time coercion_model.analyse(M, P) CPU times: user 18.5 ms, sys: 0 ns, total: 18.5 ms Wall time: 17.5 ms (['Action discovered.', Left action by Full MatrixSpace of 5 by 6 dense matrices over Integer Ring on Polyhedra in ZZ^6], Polyhedra in ZZ^5) sage: %time M*P CPU times: user 137 ms, sys: 3.39 ms, total: 141 ms Wall time: 140 ms A 5-dimensional polyhedron in ZZ^5 defined as the convex hull of 720 vertices sage: coercion_model.reset_cache() sage: %time M*P CPU times: user 256 ms, sys: 3.53 ms, total: 260 ms Wall time: 259 ms A 5-dimensional polyhedron in ZZ^5 defined as the convex hull of 720 vertices -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/c6169b79-06e0-480d-89fc-80efa3ae1e90o%40googlegroups.com.
