hello,

I'm a beginner and I just started my thesis, I'm working on a bi-objective optimization ( cost +environmental impact) for a distribution network. I managed to model the objective functions but in order to run an optimization with ILOG CPLEX I need your help. in my mathematical model I'm proposing two transport modes with two different costs, how can I process it in ILOG CPLEX ? all I find is tutorials for a network with one cost for transportation?

anyone can help and thank you in advance ( excuse my english)

asked 15 Mar '16, 11:59

hajardeq's gravatar image

hajardeq
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accept rate: 0%


CPLEX is a single objective solver. If you want to solve bi-objective problems using CPLEX you need to implement a custom solver. Two popular choices for bi-objective problems are the \(\varepsilon\)-constraint method and two-phase methods.

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answered 15 Mar '16, 14:49

Sune's gravatar image

Sune
958413
accept rate: 20%

You can take a look at this stuff: https://github.com/SuneGadegaard/TwoPhaseMethod . I do not guarantee (but I hope) that it is bug-free! It is a simple straightforward implementation of a two-phase method that use CPLEX to solve the sub-problems arising. It should work for minimization problems.

(16 Mar '16, 05:59) Sune

I'm not sure I understand your question correctly, but if you are asking what I think you are asking, just create two sets of transportation variables, one for each mode, with different costs. Anywhere you would have used a single transportation variable (e.g., the volume of A moved from B to C), you now use a sum of two variables (volume of A moved B to C using mode 1 PLUS volume of A moved B to C using mode 2).

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answered 21 Mar '16, 15:38

Paul%20Rubin's gravatar image

Paul Rubin ♦♦
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accept rate: 19%

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Asked: 15 Mar '16, 11:59

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Last updated: 21 Mar '16, 15:38

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