Constraints in Gurobi
AnsweredI have the following information:
My question is whether the following code represent the attached constraint:
state_OPM_term = gp.LinExpr()
state_OPM_term = gp.quicksum((b1["O+", "1", m, t] - (0.1 * gp.quicksum(b2["O+", "1", m, demand, t] for demand in D))* weights["O+", "1", m]) for m in M)
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Official comment
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Gurobi Staff
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Hi Shahrzad,
attached constraint
It looks like we are missing this.
- Riley
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Hi Shahrzad,
This looks correct, however this line creates an empty linear expression:
state_OPM_term = gp.LinExpr()
The next line is overwriting it, not adding to it, so the first line is unnecessary.
Just a note on the terminology, the above is not a constraint until there is a relation introduced: "<=", ">=", "==", at the moment it is just a linear expression.
- Riley
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Thank you so much Riley for your comment. As I'm using:
state_OPM_term = gp.quicksum((b1["O+", "1", m, t] - (0.1 * gp.quicksum(b2["O+", "1", m, demand, t] for demand in D))* weights["O+", "1", m]) for m in M)
as a linear expression in my objective function, would it be correct to have the following:
state_OPM_term = gp.quicksum((b1["O+", "1", m, t] - (0.1 * gp.quicksum(b2["O+", "1", m, demand, t] for demand in D))* weights["O+", "1", m]) for m in M)
obj = state_OPM_term + (the rest linear expressions)0 -
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That should work without any problems. If you did something like this and found there was an error you should verify that state_OPM_term is a LinExpr (or some other type of expression like QuadExpr) by inspecting the value of type(state_OPM_term).
- Riley
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