How can I make my constraint choose the max value?

Answered

Arif Ahmed

I have defined x[t], y[t], z[t], and I would like a set of constraints over time such that

for t in range (0,100)

m.addConstr(x[t], gurobipy.GRB.EQUAL, max_(y[t],z[t]))

However, I am getting the error name 'max_' is not defined. How do I resolve this.

Regards

Comments

5 comments

Silke Horn
Gurobi Staff

February 24, 2021 12:06

Edited
You should use the overloaded form of addConstr as follows:
```
m.addConstr(x[t] == max_(y[t], z[t]))
```
Alternatively, you can use addGenConstrMax:
```
m.addGenConstrMax(x[t], [y[t], z[t]])
```
0
Arif Ahmed

February 24, 2021 12:02
Thank you very much. The first syntax does not work for me but the second one does.
0
Silke Horn
Gurobi Staff

February 24, 2021 12:07
Glad to hear it works. There was a ")" missing in the first one. I updated it accordingly. It should work too.
0
Arif Ahmed

February 24, 2021 12:30
I get the same error with the first syntax, i.e. "name 'max_ ' not defined'

Could it be a limitation of the editor I am using?
0
Jaromił Najman
Gurobi Staff

March 01, 2021 11:14
The \(\texttt{max_}\) function is part of the \(\texttt{gurobipy}\) module. Thus, in your case, you have to access it via
```
gurobipy.max_(y[t], z[t])
```
0

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