David Torres Sanchez

1. Community
2. Modeling
3. Find max unit flow in Networkx.Graph using Gurobi

Hi Huib, Have you had a look at our Maximum Flow / Minimum Cut - gurobi-optimods documentation v2.3.1 optimod? Code: gurobi-optimods/src/gurobi_optimods/min_cost_flow.py  this function is called fr...

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• David Torres Sanchez
• January 23, 2025 16:29
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• 0 votes

1. Community
2. Algorithms
3. How to accurately calculate reduced cost when generating one column in column generation?

Hi Tanmoy, The dual values will change as adding columns will change the master problem in every iteration. This will allow you to generate more or stop if no column with a negative reduced cost ca...

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• David Torres Sanchez
• January 23, 2025 16:22
• 0 votes

1. Community
2. Systems
3. Close Active Sessions

Good catch. We allow smaller values than 5 (minutes), but these get rounded up to 5. From the same place in the docs The WLS server will cap the chosen value automatically to be at least 5 minutes...

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• David Torres Sanchez
• January 23, 2025 16:13
• 1 vote

1. Community
2. Programming
3. Kernel Dying Unexpectedly in Windows VSCode with Gurobipy

Hi Huijae, Have you profiled the failing cases? Can you share a minimal reproducible example? Cheers, David

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• David Torres Sanchez
• January 23, 2025 13:28
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• 0 votes

1. Community
2. Systems
3. Close Active Sessions

Hi Sam, Cool! The parameter is WLSTokenDuration though this needs to be set at the environment level. Similarly with other connection parameters (e.g. see mip1_remote.py). Cheers, David

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• David Torres Sanchez
• January 23, 2025 12:54
• Edited
• 1 vote

1. Community
2. Systems
3. Close Active Sessions

Hi Sam, This sounds like a WLS license. In that case, your token will be held for a minimum of 5 minutes (this can be changed with a parameter) if the environments and models are disposed of correc...

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• David Torres Sanchez
• January 23, 2025 12:12
• 0 votes

1. Community
2. Programming
3. Gurobi Error 10030: Overage for too long, X active sessions and over the baseline for Y minutes

Hi Chenying, Are you stopping the julia kernel after some time? It may that the Gurobi environments are not being disposed properly (freed) and therefore the tokens are held unnecessarily. Also if ...

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• David Torres Sanchez
• December 23, 2024 13:27
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• 0 votes

1. Community
2. Algorithms
3. Inquiry Regarding Gurobi's Recent Improvements in Network Simplex Algorithm

Hi, Or, does it mean that the user has to enter a traditional linear program with only at most one +1 and one -1 in a column and then Gurobi will "intelligently" recognize this as a network proble...

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• David Torres Sanchez
• December 16, 2024 15:16
• Edited
• 1 vote

1. Community
2. Algorithms
3. heuristic parameter and speed up the solving process

This is a pretty large problem. Upgrading your machine might help. How long does presolve take? You might want to limit this with PrePasses=1 then go straight into NoRel by setting NoRelHeurTime to...

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• David Torres Sanchez
• December 04, 2024 11:10
• 0 votes

1. Community
2. Systems
3. Error trying to use Gurobi with Python-MIP: "function/symbol 'GRBloadenv' not found in library (error 0x7f)"

Thanks Riley! I created python-mip#398 to track this. Cheers, David

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• David Torres Sanchez
• December 04, 2024 11:00
• 1 vote