Silke Horn

1. Community
2. Programming
3. Different solutions for different launches of MIP

Hi Domagoj, There are a few things that can introduce non-determinism into your Gurobi runs: Using non-deterministic data structures: When your model is created with input from external data sourc...

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• Silke Horn
• September 18, 2023 07:57
• 0 votes

1. Community
2. Algorithms
3. Incorrect solution of a conic QCP

Thank you! I can reproduce this using gurobi_cl. We recommend that objective coefficients be no bigger than 1e4, but this violation is still surprising to me.

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• Silke Horn
• August 22, 2023 10:07
• 0 votes

1. Community
2. Modeling
3. Constraint on decision variables in a multi period scenario

Hi, You are correct that you cannot access the X attribute before running the optimization. Instead, you can use indicator constraints to model something like this. This article contains additional...

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• Silke Horn
• August 22, 2023 10:00
• 0 votes

1. Community
2. Algorithms
3. Incorrect solution of a conic QCP

Hi, I cannot reproduce this so far. Could you post a complete log? Are you using any non-default parameter settings? Silke

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• Silke Horn
• August 22, 2023 06:45
• 0 votes

1. Community
2. Modeling
3. Large MILP problem

Hi Ritesh, From the log snippet you posted above, it is impossible to predict how difficult it is to solve the model, but many of our users are solving models of similar sizes. 115 GB of memory sou...

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• Silke Horn
• August 15, 2023 13:00
• 0 votes

1. Community
2. Systems
3. GPU RAM usage with Gurobi

Hi Ritesh, Please have a look at this article. (The short answer is that Gurobi does not support GPUs.) - Silke

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• Silke Horn
• August 15, 2023 12:50
• 0 votes

1. Community
2. Programming
3. Changing the NoRelHeurTime parameter for the NoRel Heuristic using Callbacks

Hi Koen, I am happy to hear that the NoRel heuristic is working so well for you. Unfortunately, it is not possible to change parameter settings in a callback. See this article for more information....

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• Silke Horn
• June 22, 2023 10:52
• Edited
• 0 votes

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2. Programming
3. Unsupported operand type(s) for *: 'float' and 'generator'

Hi, Thanks for posting your code. This looks as though some of the parentheses may be misplaced. Your objective expression is pretty long and convoluted. Maybe different formatting can help break t...

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• Silke Horn
• June 21, 2023 09:27
• 0 votes

1. Community
2. Programming
3. Unsupported operand type(s) for *: 'float' and 'generator'

Hi, Could you please clarify what type your variables have? For example, which ones are Gurobi model variables, and which are constants? Or, better yet, provide a self-contained code example so we ...

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• Silke Horn
• June 19, 2023 07:54
• 0 votes