A.Omidi

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  • Branch and price example

    Answered

    Hello everybody, Are there any B&P Java example using Gurobi? Regards Omidi. A

  • Adding the callback function

    Answered

    Dear support team, I hope you are doing well. I am trying to count the number of different solutions to a problem and have some issues.  If I write a problem as an LP format, like \(z_a + z_b = 5\...

  • Is there a preference to use Convex-hull reformulation instead of the BigM constraints?

    Ongoing

    Dear support team, I am trying to work on a scheduling problem based on its polyhedron reformulations. For that, I would like to reformulate a BigM model into its equivalent Convex hull, (CH),  for...

  • Linearizing factorial function

    Answered

    Dear community team, I'm trying to write a constraint in the following form: $$(a_j * (s_j!)) / L \leq 1-\gamma$$ Where \(\texttt{a}\) and \(\texttt{gamma}\) are constants and \(\texttt{s}\) and \(...

  • Using Gurobi heuristic parameter to achieve a feasible solution

    Answered

    Dear support team, I'm working on an optimization problem (MIP) which in the medium/large scale takes too much time to solve optimality. Then I tried to use Gurobi heuristic parameter to invoke a f...

  • MIP-Heuristic as a MIP-start

    Answered

    Dear support team,   I'm trying to solve a scheduling problem using Gurobi 9. The model is solved and the optimal solution is found. Now, I would like to use a heuristic (which an instance could be...

  • Gurobi NEOS issue

    Answered

    Dear support team,   I'm trying to solve a large scale optimization problem using Gurobi solver (V.9) on my local machine. As I have not accessed to an academic licence for Gurobi, I will need to u...

  • Special knapsack problem

    Answered

    Dear community team, I have tried to solve a special knapsack problem which contains an inequality with binary parameters. AFAIK, cover cuts families can be applied to solve the standard knapsack ...

  • Separating specific cuts

    Answered

    Dear support team, I was trying to solve a MIP using Gurobi and Java. I will need to turn off all pre-solving, heuristics and separating options and solve the problem using pure Branch and Bound. T...

  • Relaxed variable in Java API

    Answered

    Hello support team, I define an integer variable as following: GRBVar[][] start = new GRBVar[mach.length][item.length]; for (int m = 0; m < mach.length; m++) { for (int k = 0; k < item.leng...