Matthias Miltenberger

1. Community
2. Algorithms
3. Tolerances and warm-starts

Hi Dominik! We need more information to work on this, for example, log files, model files, or anything else to reproduce this issue. This is not supposed to happen, of course, and is most likely a ...

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• Matthias Miltenberger
• June 28, 2022 12:25
• 0 votes

1. Community
2. Other
3. dynamic host name

Hi Mengyuan, For this use case, you should either use a floating academic site license, that is, have your university set up a Gurobi token server that can be reached from your cluster. The other s...

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• Matthias Miltenberger
• June 23, 2022 13:41
• 0 votes

1. Community
2. Modeling
3. '<' not supported between instances of 'Var' and 'int'

You might also want to check out this article about strict inequalities: Why doesn't Gurobi support strict inequality constraints like x < a?

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• Matthias Miltenberger
• June 10, 2022 08:21
• Edited
• 0 votes

1. Community
2. Modeling
3. '<' not supported between instances of 'Var' and 'int'

Hi Putri! Please review the two links to addConstr and addConstrs that I shared above. You have to use the 's' variant if you want to use Python list comprehensions inside the call. The addConstr m...

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• Matthias Miltenberger
• June 09, 2022 11:37
• 0 votes

1. Community
2. Modeling
3. '<' not supported between instances of 'Var' and 'int'

Hi Putri, Please note that in math programming there are no strict inequalities. You need to model such restrictions by adding a small tolerance, e.g. mdl.addConstr(x[i,k] + eps <= d[k]) You should...

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• Matthias Miltenberger
• June 09, 2022 09:44
• Edited
• 0 votes

1. Community
2. Modeling
3. Infeasible subset when using computeIIS()

Hi Jingfeng, If you solve the quadratic constraint for \(\texttt{z}\), you see that this is in fact infeasible with the condition of \(\texttt{z} \geq -1\): \[\begin{aligned}- r_1^2 + r_2^2 - 6.558...

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• Matthias Miltenberger
• June 09, 2022 09:36
• Edited
• 0 votes

1. Community
2. Modeling
3. How to take the remainder of the variables in gurobi？

One more piece of advice, Yu: You can use LaTeX directly in our Community Forum as explained here: Posting to the Community Forum This is a lot less work than copy-pasting mathematical notation as ...

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• Matthias Miltenberger
• May 05, 2022 11:17
• 0 votes

1. Community
2. Programming
3. R API slower than AMPL?

Thanks for the additional information, Robert! I also noticed the different parameters being used in AMPL but wanted to make sure that at least the model that is being solved is identical for both ...

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• Matthias Miltenberger
• May 05, 2022 09:45
• 0 votes

1. Community
2. Programming
3. Documentation of Variable Update C++ vs Python interface

Hi Jonas(z) :-) This should be possible in C++ as well by reallocating the variables array and filling up the new slots with newly created variables. Or you set up the variable array large enough i...

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• Matthias Miltenberger
• May 04, 2022 10:40
• 1 vote

1. Community
2. Programming
3. Solver (gurobi) returned non-zero return code (1)

Hi Dávid, Please make sure that the file path does not contain any non-ASCII characters - this can easily lead to errors when trying to parse the path. I know, it's 2022 and we should expect a wide...

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• Matthias Miltenberger
• April 28, 2022 09:26
• 0 votes