Hello ! > You could be interested in the approach implemented in FuncDesigner LP > model:http://openopt.org/NumericalOptimizationForFuncDesignerModels#LP_example > Maybe in future I'll add FuncDesigner examples for MILP and some more > classes.
I *AM* interested in this... Thanks for the information !!! I am looking for ways to make LP easier in Sage ( it can be done now, but it is far from being as easy as in the example you show... Could you tell me how you deal with indexed variables, as x_1, ..., x_n ( and it could have to be indexed 2 or 3 times ) ? > Let me also note - statement "COIN-OR and CPLEX which have similar > performances" is completely wrong. A colleague of mine who tested them seemed to say they had similar performances (and he is likely to have spent quite a long time on that :-) ), and the link you gave seems to confirm the fact that "compared to GLPK, the solvers from COIN and CPLEX are way ahead". There seem to be another gap between COIN and CPLEX, though, you are right, I am just being kind to a colleague who did not try to betray me :-) > First of all COIN-OR project is a set of solvers (LP, NLP, etc), not > an LP/MILP solver. I was talking about Cbc, I often do it as COIN if a bit more famous than Cbc > At second, it is well-known CPLEX is too far ahead of any free MILP > solver. > See for example the bench by Hans Mittelmann (one of most > authoritative), where CPLEX is 6 times faster of fastest free MILP > solverhttp://forum.openopt.org/viewtopic.php?id=18 The interface with COIN which is to be ( I hope ) one day merged to Sage uses Osi, which also provides an interface to CPLEX. To build a support for CPLEX, one would only need to replace the string "Cbc" by "Cplex" in the source code, which takes O(1) time. I will be able to do it myself pretty soon, so Sage will also be able to use CPLEX :-) In the meantime, and even if I only talk about its graph-theoretic applications, Sage already gained a LOT from the integration of Cbc and GLPK... I will do what I can from now on to integrate a good support for MIP... Thanks a lot for your remarks !! :-) 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 -~----------~----~----~----~------~----~------~--~---
