Help with MILP formulation. #80
Description
I am trying to formulate a QUBO for a MILP scheduling problem which has 3 equations and an objective function. The model is formulated as
RTN=Model(Gurobi.Optimizer)
@constraint(RTN, Balance[r in R, t in T1],
X[r,t] -
(X[r,t-1]
+ ∑(
μ[i,r,θ] * N[i,t-θ]
+ ν[i,r,θ] * ξ[i,t-θ]
for i in Ir[r], θ in 0:max_tau if θ ≤ tau[i] && t-θ ≥ 1
)
+ Π[r,t])==0
)
@constraint(RTN, ResourceLB[r in R, t in T1],
X[r,t]-Xmin[r]>=0
)
@constraint(RTN, ResourceUB[r in R, t in T1],
Xmax[r]-X[r,t]>=0
)
@constraint(RTN, BatchLB[i in I, t in T1],
ξ[i,t]- ( Vmin[i] * N[i,t])>=0
)
@constraint(RTN, BatchUB[i in I, t in T1],
Vmax[i] * N[i,t]-ξ[i,t]>=0
)
@objective(RTN,
Min,
∑(N[i,t] for i in I, t in T1)
)
Here, N[i,t] is a binary variable, X[r,t] and ξ[i,t] are continous variables, rest all are parameters. I am able to solve this model with gurobi to an objective value of 5 in under a second (which it should be), but when I use the TOQUBO.jl to reformulate it as a QUBO and solve the problem my objective value reached in the range of 1e16 and takes around 300+ seconds.
To convert to QUBO, I implement the model as
RTN=Model(() -> ToQUBO.Optimizer(DWaveNeal.Optimizer))
And then write the above constraints and objective.
Am I missing something? Kindly help me with this implementation.