Steven Edwards

Gurobi Staff Gurobi Staff
  • Total activity 43
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Activity overview

Latest activity by Steven Edwards

  • Steven Edwards created an article,

    Highlights of past Gurobi releases

    1. What's New
    2. Releases

    Detailed release notes are included with each of the major, minor, and technical releases. Here is a brief and non-exhaustive summary of a number of key features that were included in each of our m...

    • Steven Edwards
    • Updated
    • 2 followers
    • 0 comments
    • 2 votes

  • Steven Edwards created an article,

    How do I request a transfer of my Gurobi license?

    1. Knowledge Base
    2. Accounts and Licensing
    3. Other Licensing Topics

    Some Gurobi license types work by registering the license to a specific machine. In some cases, the license is registered to a single user on that machine. Note: For all licenses that use our WLS (...

    • Steven Edwards
    • Updated
    • 1 follower
    • 0 comments
    • 0 votes

  • Steven Edwards created an article,

    Error code 10009: Token validation error (status 8)

    1. Knowledge Base
    2. Common Error Messages
    3. Errors when running Gurobi

    The error ERROR 10009: Token Validation Error (status 8) typically indicates that the internal clock of the machine or container running Gurobi is out of sync with our license server. Our license s...

    • Steven Edwards
    • Updated
    • 1 follower
    • 0 comments
    • 0 votes

  • Steven Edwards commented,

    1. Community
    2. Modeling
    3. Unbdray does not give me correct answer

    Hi Zahra. What exactly is the error that is raised when you try and add the feasibility cut?

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  • Steven Edwards commented,

    1. Community
    2. Other
    3. automatic scaling of a problem in advance, before calling the solver to solve it

    Hi Johan, Apologies for the delay. It's an interesting idea. Do you mean like an automated tool for advanced user-scaling? If so, I have been playing around with an idea that could be useful for th...

  • Steven Edwards commented,

    1. Community
    2. Modeling
    3. Why is this model infeasible?

    Hi Vadim, I had a quick look and I don't believe there is a way to remove the z variables completely (I might be wrong). Given the equality constraints in    solver.addConstr(z[time_interval + 1] =...

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  • Steven Edwards commented,

    1. Community
    2. Modeling
    3. Why is this model infeasible?

    Hi Vadim, Thanks for the clarification. Yes, it should be possible to express the model just in terms of the x and y variables. Well really, you only need the first of the x variables, x[0]. From x...

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  • Steven Edwards commented,

    1. Community
    2. Modeling
    3. Why is this model infeasible?

    Hi Vadim, Glad to hear you resolved the issue :-). It isn't clear to me what you mean by "define z to be a dictionary and not a variable, Gurobi tells me the model is infeasible". I would encourage...

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  • Steven Edwards commented,

    Official comment
    1. Community
    2. Modeling
    3. Why is this model infeasible?

    Hi Vadim, Thanks for reaching out. I tried running that code you sent through and I get a feasible solution, although slightly different from the one you mention; mine has X=3. It is not clear to m...

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  • Steven Edwards commented,

    1. Community
    2. Programming
    3. Optimization failed after presolve

    Hi Sean, Thanks for reaching out. That is quite peculiar. I notice that you are using 9.1.1 and also that a Compute Server Worker is involved. Can you first try upgrading to 9.1.2 and seeing whethe...