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General expression : min_ or max_




  • Eli Towle
    Gurobi Staff Gurobi Staff

    The min_() helper function can only be used to set one variable equal to a group of variables and/or constants. This would be used if, e.g., you want to add a constraint like \( x = \min\{y, z, 2\} \), where \(x\), \(y\), and \(z\) are variables.

    In your case, the elements of \( \texttt{index} \) are not variables. Thus, the minimum of \( \texttt{100} \) and \( \texttt{sum(100 for i in index if == 0)} \) is a constant value that doesn't depend on any variables. This means you can use Python's built-in \( \texttt{min()} \) function:

    model.addConstr(quicksum(100*schedule[i] for i in index) <= 100 - min(100, sum(100 for i in index if == 0)))

    Note that I used Python's built-in \( \texttt{sum()} \) function instead of Gurobi's quicksum() function. The latter returns a LinExpr object, which won't work well with \( \texttt{min()} \).

  • Sung Ook Hwang
    First Comment
    First Question

    Thank you Eli for your help!


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