Nathann Cohen wrote: >> Yes, you can use indexation like some_oovar[i] or some_oofun[i] >> (probably with several indexes, or negative ones that are start from >> array end), however, I think it should be avoided if possible (you'd >> better split your oovar into several >> oovars).http://www.openopt.org/FuncDesignerDoc#Some_issues_to_be_aware > > I sent a message on sage-support to know to which extent I could use > multivariate Polynomials in Sage to represent constraints and Linear > functions, but it seems to be troublesome... This said, there is no > way for me to use Linear Programming if I can not use indexed > variables... At the moment, even though the syntax could be > tremendously improved, I can use any hashable Sage object as a > variable, and most of the time in Graph theoretic function my > variables are edges, vertices, or arbitrary tuples and strings. > Anyway, most of the Linear Programs are generated from graphs and I > have to find a way to let a computer create as many variables as > possible :-/ > The current syntax, though, is not nearly satisfying. >
I should mention that at various times, people have proposed that you could create symbolic variables x[1], x[2], etc. As far as I know, these proposals have just been ideas and have never been implemented or experimented with. Maybe we could make x[1] a symbolic variable automatically. We would have to make an indexing function for symbolic variables that would return a symbolic variable that would be cached somewhere (so that x[1] always referred to the same variable). That would also give us nested indices, as x[1][1] would take a symbolic variable x, create a new one x[1], and then x[1] would create another symbolic variable x[1][1]. Jason --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
