Decision Optimization

Decision Optimization

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  • 1.  How to Retrieve Extreme Rays

    Posted 05/04/20 02:44 AM
    Hello Everyone, 


    I am solving a very simple LP, as part of a column generation, where the primal problem is unbounded (i.e. the dual is infeasible), for which I have to retrieve the direction of unboundedness a.k.a. extreme rays. 

    The extreme rays I am looking for are r1 = (1,0) & r2 = (4,1).



    The model is as follows:


    dvar float+ x1;
    dvar float+ x2;
    
    minimize -100 - 299 * x1 - 399 * x2;
    
    subject to {
    
    ct1: -x1 + 4 * x2 <= 8;
    ct2: x2 >= 2;
    
    } 
    
    execute DISPLAY_RESULT {
    
    writeln("Obj Value of SP= " + cplex.getObjValue());
    writeln("x1 = " + x1);
    writeln("x2 = " + x2);
    writeln("dual of ct1 = " + ct1.dual);
    writeln("dual of ct2 = " + ct2.dual);
    
    }​



    I would appreciate if you could kindly help me with obtaining the extreme rays in this simple LP.

    Regards

    BMB



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    Bahman Bornay
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    #DecisionOptimization


  • 2.  RE: How to Retrieve Extreme Rays

    Posted 05/04/20 02:45 AM
    Duplicate of this question

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    Daniel Junglas
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