Originally posted by: SystemAdmin

[chacha said:]

Hello everybody!

I´m just learning OPL since two months and i use OPL Studio 3.7.
My questions are:
What is the diffrence between CPLEX MIP and SOLVER MIP?
Which algorithm use CPLEX MIP and SOLVER MIP?

Thanks for your help!
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[jfk said:]

Hello,
I'm surprised that you are using OPL3.7... the present version is OPL6.3... with the new version beside the improvements you get on the modeling+IDE side you will get the latest solving engines of CPLEX and CPO (CP Optimizer) (you can download a trial (or obtain a free Academic version) here:
http://www.ilog.com/products/optimization/ - right side column at the middle

as to the engine algorithms
CPLEX is a mathematical programming engine: it has some LP algorithms implemented and then it uses "branch and cut" for MIP.
Solve is a constraint programming engine (actually MIP is misleading since the variables all have to be integer): it uses many propagation algorithms and essentially the tree-search can be controlled by the user.

if you go to the Options menu point then you will see all the details what I'm talking about above...

I hope it helps

cheers
#DecisionOptimization
#OPLusingCPLEXOptimizer

Originally posted by: SystemAdmin

[chacha said:]

Hello jfk,
thanks a lot for your answer it helps me a lot.

I´m using version OPL3.7 in my university and right now i´m the only one who is using OPL.
OPL was installed years ago for a project to solve scheduling problems and may be we don´t have the present version because OPL fall into disuse. But thank you for advice, I will ask for the present version.

I try the several algorithms at the menu point Options, but the calculating time doesn´t change. My aim is to get the solution in the shortest possible time with the optimize algorithm. But my model is maybe to simple, so the calculating time doesn´t change.

best regards


 

#DecisionOptimization
#OPLusingCPLEXOptimizer