Why "constraint has no bool value (are you trying "lb <= expr <= ub"?)"

Answered

MA MENGYUAN

December 13, 2022 13:38

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mdl.addConstrs(quicksum(x[0,i,k] for i in N) == (y[j,0,k] for j in N) <= 1 for k in K)
mdl.addConstrs(u[i,p,k]-u[j,p,k]+m[p]*x[i,j,k] <= m[p]-q[j,p] for i in V for j in V if i!=j
for k in K for p in P)

My code has this error "constraint has no bool value (are you trying "lb <= expr <= ub"?)"

Can someone help me?

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  Jaromił Najman

  • Gurobi Staff

  December 13, 2022 14:26

  Your first constraint

  mdl.addConstrs(quicksum(x[0,i,k] for i in N) == (y[j,0,k] for j in N) <= 1 for k in K)

  reads \(\sum_{i \in N} x_{0,i,k} = y_{j,0,k} \forall j \in N \leq 1 \forall k \in K\). As you can see there is definitely at least one (in)equality too many.

  For additional details, please refer to the Knowledge Base article Constraint has no bool value (are you trying "lb <= expr <= ub"?).

  Best regards, 
  Jaromił

  Best regards, 
  Jaromił

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  MA MENGYUAN

  December 13, 2022 14:36

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  Dear Jaromil,

  Thanks a lot. 

  Best regards,

  Ma

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