Decision Optimization

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CPLEX Error 5002: Q in ''q1'' is not positive semi-definite

  • 1.  CPLEX Error 5002: Q in ''q1'' is not positive semi-definite

    Posted 28 days ago
    Why I'm getting the following error when multiplying two decision arrays elementwise.

    sum(g in pr)(P1producedperiody[t][g]*P1produceperiodx[t][g])
     P1producedperiody[t][g]: decision array of type integer
     P1produceperiodx[t][g]: decision array of type boolean

    Is this the proper way to multiply two arrays elementwise?...

    Error:
    CPLEX Error 5002: Q in ''q1'' is not positive semi-definite


    Can anyone help?

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    Muhammad Ismail
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  • 2.  RE: CPLEX Error 5002: Q in ''q1'' is not positive semi-definite

    Posted 28 days ago
    Hi,

    in How to with OPL ? I gave some examples:

    How to multiply two binary decision variables ?
    How to multiply a decision variable by a boolean decision variable in CPLEX ?
    How to multiply an integer decision variable and a second decision variable ?
    How to multiply two float decision variables ?​


    I recommend the 2nd one:

    // suppose we want b * x <= 7 
    
        dvar int x in 2..10;
        dvar boolean b;
    
        dvar int bx;
    
        maximize x;
        subject to
        {
          
        // Linearization  
        bx<=7;
    
         
    
        2*b<=bx;
        bx<=10*b;
    
        bx<=x-2*(1-b);
        bx>=x-10*(1-b);
        
        // if we use CP we could write directly
        // b*x<=7
        
        // or rely on logical constraints within CPLEX
        // (b==1) => (bx==x);
        // (b==0) => (bx==0);
        }






    ------------------------------
    [Alex] [Fleischer]
    [EMEA CPLEX Optimization Technical Sales]
    [IBM]
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