Chung-Kyun Han

1. Community
2. Modeling
3. Multi Objective Best Solution

Hi Joseph, Thank you for reaching out. We recommend you look through our page about Multiple Objectives first.Especially when you read Working With Multiple Objectives page, you can realize how Gur...

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• Chung-Kyun Han
• July 25, 2023 08:14
• Edited
• 0 votes

1. Community
2. Algorithms
3. Presolve for a very large LP

Hi Dong Han Thank you for reaching out and sharing the log. Your first question is “why the number of constraints removed during presolve is lager than the number of constraints in the original mod...

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• Chung-Kyun Han
• July 21, 2023 05:32
• Edited
• 0 votes

1. Community
2. Programming
3. Modèle solved with a 0 Objective function

Hi Rayan, Thank you for sharing your problem and model file.If you don't mind, please share the model file through other cloud storage services such as Filemail, Dropbox, Box, Google Drive, OneDriv...

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• Chung-Kyun Han
• July 17, 2023 03:13
• 0 votes

1. Community
2. Modeling
3. bad operand type for abs(): 'gurobipy.LinExpr'

Hi İrem,   Thank you for sharing your model. We first share the entire codes representing your mathematical model and then we will add explanations. import gurobipy as gpimport numpy as npresources...

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• Chung-Kyun Han
• July 14, 2023 14:29
• 0 votes

1. Community
2. Programming
3. Modèle solved with a 0 Objective function

Hi Rayan, We would like to suggest two approaches to validate your model. If you already know a solution having better objective value, fix variables based on the solution and validate the feasibil...

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• Chung-Kyun Han
• July 13, 2023 14:39
• 0 votes

1. Community
2. Programming
3. Print intermediate solutions (Objective value and variables) while running MIP using gurobi in python.

Hi Bhargav Gorantla Sridhar,   Thank you for reaching us. I would like to introduce two approaches that handle intermediate solutions.The simple one is to write .sol file by SolFiles parameter and ...

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• Chung-Kyun Han
• July 13, 2023 00:29
• Edited
• 0 votes

1. Community
2. Modeling
3. bad operand type for abs(): 'gurobipy.LinExpr'

Hi İrem,   Thank you for reaching us. If you don't mind, could you share the mathematical formulation of the constraint you want to add?I mean, the following constraint. for i in range(resources): ...

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• Chung-Kyun Han
• July 10, 2023 13:36
• Edited
• 0 votes

1. Community
2. Programming
3. Modèle solved with a 0 Objective function

Hi Rayan, Thank you for reaching us.I'm happy to support you again :D Could you give us more information about why you consider the solution wrong?Do you already know a feasible solution whose obje...

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• Chung-Kyun Han
• July 10, 2023 13:12
• 0 votes

1. Community
2. Programming
3. Branching priority to MVars

Hi Andrea, Thank you for reaching us. Suppose you don't call m.model(), you cannot check your modification on the variables' attributes directly.Try the below code. for v in y:    v.setAttr('Branch...

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• Chung-Kyun Han
• July 07, 2023 00:09
• 0 votes

1. Community
2. Modeling
3. Gurobi says the model is infeasible, yet I can come up with a solution by hand (Python)

Thank you for reaching us. The default lower bound of a variable is zero (please refer to our manual about Model.addVar()).If you add variables like as follows, you will get the optimal solution yo...

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• Chung-Kyun Han
• July 06, 2023 02:35
• 0 votes