Create a variable which is rounding of another variable
AnsweredHi,
I want to create a variable which is round of another variable or use the rounded variable for my objective function. Example as below
I have a flow variable which iterates on a key (flow_variable). I need to find the number of trucks for the flow based on the calculated variable. the max capacity of truck is 1500.
So number of trucks = round (flow_variable/1500). But gurobi shows an error unable to use the round function on the variable. Any suggestions on how to do this are welcome?
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In addition to the real-valued variable flow_variable, you can define the integer-valued variable trucks (preferably with an upper bound based on the fleet).
Let capacity=1500 be the capacity of a single truck. Then, you can define the following functional constraints:
capacity * (trucks - 1) <= flow_variable <= capacity * trucks
Note: depending on the formulation of your model and/or optimality conditions, you may actually only require the second constraint.
With this in place, you can easily incorporate the decision variable trucks into the objective function.
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Thanks for the suggestion. Juan Orozco
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