Getting the objective value of a specific solution.

[thomasgudjonwright]

Hi!

I apologize if I am missing something obvious, but I am wondering how one would access the objective value of a given solution. I see that you have a validate method which verifies the candidate solution is feasible. I first thought I could do this via JuMP.value, however variable names seem to all be noname in model[:obj] so I am unable to create a function from the key to values in the solution Dict. Any thoughts or easy solutions I am missing?

Thanks in advance!

Tom

[iSoron]

Hi @thomasgudjonwright, after you have built the model with UnitCommitment.build_model(...) and solved it with UnitCommitment.optimize!(model), you can query the objective value by using JuMP.objective_value(model). For example:

using Cbc
using JuMP
using UnitCommitment

instance = UnitCommitment.read_benchmark("matpower/case118/2017-02-01")
model = UnitCommitment.build_model(
    instance=instance,
    optimizer=Cbc.Optimizer,
)
UnitCommitment.optimize!(model)
@show JuMP.objective_value(model)

If you are trying to query the value of each decision variable instead, that's described in our documentation.

[thomasgudjonwright]

Thanks for the quick reply, @iSoron ! I may not have been clear, sorry! I meant if I have used some external model to generate a solution. ie the solution is not stored within the optimized model, but is being loaded from a .json for example. Does this explanation help clarify my question?