Bounds for Variable

Answered

ALESSANDRA VIEIRA

February 09, 2024 10:03 Edited

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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++) {
    ostringstream vname;
    vname << "Wcurt" << t;
    // Wcurt[t].set(GRB_CharAttr_VType,GRB_INTEGER);
    Wcurt[t].set(GRB_DoubleAttr_UB, P_wind[t]);
    Wcurt[t].set(GRB_DoubleAttr_LB, 0);
    Wcurt[t].set(GRB_StringAttr_VarName, vname.str());
}

P_Wind[t], is a float array type;
W_curt can be continuous;

 

I appreciate any help.
Best regards,

 

As a syntax, what means the C++ syntax is wrong, however that also has to do with the GRBVar is created, meaning as also an array.

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• Official comment

  

  Simranjit Kaur

  • Gurobi Staff

  November 13, 2026 01:30

  This post is more than two years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support.
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  Matthias Miltenberger

  • Gurobi Staff

  February 09, 2024 10:46

  Hi Alessandra!

  I am not sure I understand the problem or the error here. Could you please share a minimal reproducible example, including the error message?

  Thanks,
  Matthias

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  ALESSANDRA VIEIRA

  February 09, 2024 15:03

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  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[ ], my code is Gurobi C++ in VS. I just one be sure, is not problematic for a GRB_VAR have such output as UB.

  I would be very kind, to let me know about it.

  Best Regards,

  Alessandra

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  Matthias Miltenberger

  • Gurobi Staff

  February 09, 2024 16:46

  Hi Alessandra,

  This should be fine. Just be aware that you cannot have dynamically changing values (e.g. the output of a function that is part of your problem) as model parameters. The upper bound has to be a fixed value for Gurobi.

  I hope that answers your question.

  Cheers,
  Matthias 

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