How to represent the sum of binary variables ？

Answered

k k

June 28, 2025 23:36

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I am solving a SMT problem with gurobi.

Some restrictions are listed below.

 

I represent them with the following code.

##con4
for i in range(self.in1.i):
    constraint_scheduling += [
        quicksum(x[i,d,t] * self.in1.l_t[t] for d in range(self.in1.d) for t in range(self.in1.t)) <=
        self.in1.b_max[i]]
    constraint_scheduling += [
        quicksum(x[i,d,t] * self.in1.l_t[t] for d in range(self.in1.d) for t in range(self.in1.t)) >=
        self.in1.b_min[i]]

##con6
for i in range(self.in1.i):
    for s in range(1, self.in1.c_min[i]):
        for d in range(self.in1.d - s - 1):
            constraint_scheduling += [quicksum(x[i,d,t] for t in range(self.in1.t))
                                      + s - quicksum(x[i,j,t] for j in range(d + 1, d + s + 1) for t in range(self.in1.t))
                                      + quicksum((x[i,d + s + 1,t] for t in range(self.in1.t))) >= 1]

Are those correct?

 

 

Related to

• Big-M

0

• 

  Riley Clement

  • Gurobi Staff

  July 02, 2025 05:37

  Hi,

  This looks sort of correct to me.

  You are creating TempConstr objects and then adding them to some constraint_scheduling object.  Generally you would add use addConstr( ) to add these TempConstr objects to the model.

  I guess it is possible you have created a constraint_scheduling object where the add operator appends these TempConstr to a list, and these TempConstr are added to the model later, but it seems more likely that a LLM has given you code that is a mixture of gurobipy and some other 3rd party framework.

  - Riley

  0
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  k k

  July 02, 2025 22:30

  • 
  • 

  Thank you,I have already found out where the problem lies.

  0

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