Sophie Wuyckens

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Latest activity by Sophie Wuyckens

  • Sophie Wuyckens commented,

    1. Community
    2. Modeling
    3. How to generate lower bounding constraints ?

    I see. Well here is the thing, I have tried a model where I was trying to minimize a function \(f'\) directly representing a linear combination of binary variables associated with additional flow c...

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    • Sophie Wuyckens
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  • Sophie Wuyckens commented,

    1. Community
    2. Modeling
    3. How to generate lower bounding constraints ?

    Sure. Here is a link. Thank you for your help.

  • Sophie Wuyckens commented,

    1. Community
    2. Modeling
    3. How to generate lower bounding constraints ?

    Hi Jaromil, I tried both solutions you proposed and it does not change anything, it still solves the LP and stops there. Using mipsol call back, it complains I don't use MIPNODE while using cbGetNo...

  • Sophie Wuyckens commented,

    1. Community
    2. Modeling
    3. How to generate lower bounding constraints ?

    Hi Jaromil, Yes that's the thing. No nodes are displayed at all. The model finds an optimal solution and stops. Thank you for your follow up. Gurobi 9.5.0 (linux64) logging started Thu Jun  9 17:5...

  • Sophie Wuyckens commented,

    1. Community
    2. Modeling
    3. How to generate lower bounding constraints ?

    Hi Jaromil, Marika, I don't have difficulties to include a callback. It actually enters the callback, what it does not is to enter the condition where == GRB.Callback.MIPNODE. Anyways, here is my c...

  • Sophie Wuyckens created a post,

    How to generate lower bounding constraints ?

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    1. Community
    2. Modeling

    Hello, I would like to implement a branch-and-cut decomposition by minimizing a lower bounding variable z. The idea is to solve a relaxed version of my model (*) and then iteratively modify it by i...

    • Sophie Wuyckens
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  • Sophie Wuyckens commented,

    1. Community
    2. Systems
    3. Is there a way to limit the memory used by Gurobi algorithms ?

    Hi Jaromil, Thank you very much. Very informative, exactly what I needed to know. Regards, Sophie

  • Sophie Wuyckens created a post,

    Is there a way to limit the memory used by Gurobi algorithms ?

    Answered
    1. Community
    2. Systems

    Hi, I am working with big models for which the barrier method seems to be the most approriate solver according to my tuning tests. However, this algorithm uses tremendous memory ressources. Given t...

    • Sophie Wuyckens
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  • Sophie Wuyckens commented,

    1. Community
    2. Programming
    3. Get variables by name

    Hi Maliheh, I saw this solution but the problem is I want to only access specific variables by name and not by the variable object.I tried the following but I still get an error: names_to_retrieve ...

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    • Sophie Wuyckens
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  • Sophie Wuyckens commented,

    1. Community
    2. Programming
    3. Get variables by name

    Hi Maliheh, Quick question, I wanted to know the value of some of my variables during the optimization using a callback function (where=MIPSOL). However, I get an error during the callback when I w...