Hello everybody !!!! I had a difficult time trying to find a way, in Linear Programming, to neatly define a sum over a set of elements... This, because I would like to write a clean function __latex__ for MIP, and that I can not just output all the constraints, as most of them are of the form \forall v , \forall i, and I can not just enumerate them.
I thought it would be way better to output in LaTeX beautiful equations with the \forall v, \forall i, \sum, etc, which take only 2 or 3 lines when enumerating the constraints would take one hundred and be impossible to read. Besides, it would make the functions much more efficient by cythonizing them. Well, I solved it by convincing myself it was not my job, which was a pretty good idea : Is there a way in Sage to define a Formal sum ? Something like sum( a_i, i \in [0,...5] ) or even worse, sum(a_e, e\in g.edges()) for g a graph, etc. I insist it should be a "formal sum", as it should not return sum ( [a_i for i in range(6) ] ) or sum( [a_e for e in g.edges() ] ) , but rather an abstract formula for this. It could be evaluated at any moment, giving different results if the a_i have changed or if the graph has changed meanwhile. I think it should not be that obvious at all, though not at all a waste of time to me.... Could I have your advice about it ? :-) Nathann --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
