Miranda

Gurobi-versary
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Activity overview

Latest activity by Miranda
  • Miranda created a post,

    Running time is longer when the problem size is decreased

    Answered

    Hello,  I have a question regarding the Gurobi solver. I solved two mixed integer programmings (named MIP1, and MIP2 respectively) which are in the same structure/formulation (they are all set-pack...

  • Miranda created a post,

    Is TimeLimit counting the cpu time or system time ?

    Answered

    Hello, Gurobi can set the time limit by setting the parameter TimeLimit, but I am wondering is the Timelimit parameter set for total CPU time or system time (the time used to solving the model excl...

  • Miranda created a post,

    Adding constraints to linear program

    Answered

    Hello, I am currently solving a problem by adding new constraints to a linear program at each iteration, and then resolve the linear program from the beginning. I am curious about if there is any w...

  • Miranda created a post,

    model the minimization of sum of inverse functions

    Answered

    Hello, The problem I am solving is to minimize sum of 1/x[k] for k in range(n), under a set of linear constraints. I set the lower and upper bounds for each x[k] be greater than 0; therefore, 1/x i...

  • Miranda created a post,

    Get the total number of added cuts by Gurobi

    Answered

    Hello, After running the MIP model via Gurobi, the log file sometimes provides me how many certain cuts are added. Is it possible for me to get the total number of added cuts directly?  For example...

  • Miranda created a post,

    Root relaxation objective value is different from the objective value from continuous model

    Answered

    Hello everyone,  I have a question regarding the root relaxation objective value.  The problem I am trying to solve is an integer program(IP). I modeled my problem as integer program (i.e. variable...

  • Miranda commented,

    Hello Matthias, Thank you for your quick response. I am currently model my problem as MIP and use callback function to add cuts. In my callback function, I set if where == GRB.Callback.MIPSOL, and ...

  • Miranda commented,

    Followup: I am guessing that I could model my original MIP problem in Gurobi and then use callback function to add my cuts during Gurobi's branch and bound process. Am I right? However, in my callb...

  • Miranda created a post,

    implement cutting plane algorithm

    Answered

    Hello, I am trying to find the optimal integer solution of a IP by solving a sequence of LPs instead of MILPs. What I am currently doing is I resolve the entire LP from sketch after adding some ce...

  • Miranda created a post,

    How do I know the total running time used to get the optimal solution? (Understand the outputs of Gurobi)

    Answered

    Hello, I got confused about understanding the outputs of Gurobi. I formulate a problem as a mixed integer program via Gurobi.  I used the code 'model.optimize()' to find its optimal solution, and I...