Mario Ruthmair

1. コミュニティ
2. Algorithms
3. Ignored lazy constraint leads to wrong solution cont.

Hi Florian, Yes, since many CVRP cut families cut off integer solutions, too, I would strongly recommend adding all your cuts with addLazy(). There is no downside to this; in fact, you might even b...

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• Mario Ruthmair
• 2025年02月21日 08:33
• 0 件の投票

1. コミュニティ
2. Algorithms
3. Ignored lazy constraint leads to wrong solution cont.

Hi Florian, You mentioned that you add the RCCs in the MIPNODE callback with addCut(). What happens if you add them in MIPNODE with addLazy()? Can you still reproduce the issue?This was my workarou...

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• Mario Ruthmair
• 2025年02月10日 07:27
• 0 件の投票

1. コミュニティ
2. Algorithms
3. VRPTW BIGM problem

Hi Giovanni, Gurobi provides a general-purpose solver, while Hexaly provides specific interfaces to particular problem types, e.g., routing problems, which allows the use of problem-specific soluti...

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• Mario Ruthmair
• 2024年11月25日 11:52
• 0 件の投票

1. コミュニティ
2. Modeling
3. Enforcing arc (a,b)=1 in branch and price algorithm for routing problem

Hi Krypt, Sometimes, people add binary arc variables x(a,b) that are actually not needed in a route formulation. But you can do some stuff with them, e.g., branching, additional cuts, etc.Of course...

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• Mario Ruthmair
• 2024年10月24日 14:59
• 0 件の投票

1. コミュニティ
2. Systems
3. Issue with setting up Windows Token Server

Hi David, Yes, indeed, the WLS academic license requires a permanent internet connection since it requests a license token from our servers every 5 minutes. Best regards,Mario

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• Mario Ruthmair
• 2024年10月15日 09:29
• 1件の投票

1. コミュニティ
2. Systems
3. Issue with setting up Windows Token Server

Hi David, Your named-user license, unfortunately, does not work with a token server.For a WSL2 setup, we recommend the so-called "WLS Academic" license (WLS = Web License Service). You can generate...

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• Mario Ruthmair
• 2024年10月15日 09:17
• 0 件の投票

1. コミュニティ
2. Programming
3. Gurobi running out of memory in loop, but deleting environment every iteration

Here is a bug report: https://support.gurobi.com/hc/en-us/articles/27635574446353-Memory-leak-in-gurobipy-with-Python-3-12

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• Mario Ruthmair
• 2024年08月19日 13:46
• 0 件の投票

1. コミュニティ
2. Programming
3. Gurobi running out of memory in loop, but deleting environment every iteration

Our developers narrowed it down to a memory leak related to the Cython version used to build gurobipy 11.0.x. We are using a newer Cython version for the coming 12.0.0 release, so the issue will be...

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• Mario Ruthmair
• 2024年08月19日 10:26
• 0 件の投票

1. コミュニティ
2. Programming
3. Constraint in Gurobi

Hi Shahrzad, If all variables p(s) on the right-hand side exist from the beginning and are not created via column generation (and only \rho(s,a) are generated), I guess you can define the complete ...

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• Mario Ruthmair
• 2024年07月23日 09:03
• 0 件の投票

1. コミュニティ
2. Programming
3. Cannot retrieve dual variables even after fixing all binary variables and resolving

Hi Shahin, The constraint indices are created and maintained by Pyomo, not by Gurobi.From the Gurobi side, you need to ensure that the optimization result is "optimal" to obtain the dual values. Mario

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• Mario Ruthmair
• 2024年07月22日 07:50
• 0 件の投票