Max_ for multidimensional array

Answered

Ana Guasque Ortega

May 13, 2021 15:16

Hi,

I have a multidimensional variable:

var = m.addVars(N,time,vtype=GRB.INTEGER, name ="Var_")

and I would like to calculate the maximum value of this variable for each N. For example,

max_var[0] is the maximum in value of var[0, t] in all time. I have defined this variable:


max_var = m.addVars(n,vtype=GRB.INTEGER, name ="MaxVar_")

and the constraint is:

m.addConstrs( (max_var[n] == max_(var[n,t]) for n in N), "cMaxValues")

but it always returns the last element in var[n,t]. Am I in the correct way or Gurobi needs only lists for the max_ function?

Thanks!

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Comments

3 comments

Official comment
Simranjit Kaur

Gurobi Staff

June 23, 2025 02:54 Edited
This post is more than three years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum. Or why not try our AI Gurobot?.
Jaromił Najman

Gurobi Staff

May 14, 2021 11:46 Edited
Hi Ana,

The term
```
max_(var[n,t])
```
only takes the maximum value of exactly one variable \(\texttt{var[n,t]}\) because the object \(\texttt{var[n,t]}\) is exactly one variable at position \(\texttt{(n,t)}\). To take the maximum value over all \(\texttt{t}\), you have to construct a list
```
max_(var[n,t] for t in range(time))
```
Best regards,
Jaromił
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Ana Guasque Ortega

May 17, 2021 09:54
Many thanks for your response!!!

Finally it works!
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