ALESSANDRA VIEIRA

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Latest activity by ALESSANDRA VIEIRA
  • ALESSANDRA VIEIRA commented,

    Hallo gurobot!  The question is :  GRBVar x;GRBLinExrpr b;GRBQuadExpr c;GRBLinExpr d;c=6*x;d=x+x;b= c+d; The solver does not accept, the sum of expr can be easily a LinExpr, but  I think is because...

  • ALESSANDRA VIEIRA commented,

    Hi Matthias, The problem is my array P_wind is one single function output, that was randomly chosen from one data  2-D array [T][N] that will be the Upper Bound (UB) for the Gurobi variable W_curt[...

  • ALESSANDRA VIEIRA created a post,

    Bounds for Variable

    Answered

    I am using Gurobi 9.0, with C++. I am trying to put an array element, that is created for a C++ function ( use random) as a UPPER bound of a GRB Var array, as follows: for ( t = 0; t < z; t++) {  ...

  • ALESSANDRA VIEIRA commented,

    I already had noted my mistake but Thanks a lot!   

  • ALESSANDRA VIEIRA created a post,

    Gurobi C++ expr sum

    Answered

    Hi Folks, I need some help with my code. I am using Gurobi C++. I did a QuadExpr sum += sum of GRBVar variables.  How is possible that this sum gives any value different than zero if my variables a...

  • ALESSANDRA VIEIRA commented,

    Hallo Jaromil, Yeah ... because if I join it then I get the error message about the list of arguments. "subproblem1 cb = subproblem1(P_wind,t_D_f,Pbss,Pbssd,Ecurrent); Severity    Code    Line    D...

  • ALESSANDRA VIEIRA commented,

    Hallo Jaromil,   I think we mismatch answers and questions please find above the piece of my callback.

  • ALESSANDRA VIEIRA commented,

    Hallo Jaromil,    Please find below the instantiation of part of the callback, that will be applied at the solution node. After I commented Ecurrent expression, then the optimization runs, without ...

  • ALESSANDRA VIEIRA created a post,

    Calback in C++ : list of arguments

    Answered

    I'm trying to use a callback to add a cut that equals a Gurobi expression, which sums a variable, at different times. If I keep the expression in the list of callback arguments, I get an error mess...

  • ALESSANDRA VIEIRA commented,

    Hi David, Really thanks for your answer!  "In the logs, you are showing, the optimality gap has not reached that point", so why the optimization has stopped if no time limit was set? BR, Alessandra.