Using `empty!` with `OptimizerWithAttributes`

[xinkai-zhou]

If I do MOI.OptimizerWithAttributes(KNITRO.Optimizer, "algoritm"=> KNITRO.KN_ALG_BAR_DIRECT), and then use MOI.empty!(optimizer) before adding variables, I'd get MethodError: no method matching empty!(::MathOptInterface.OptimizerWithAttributes).

[blegat]

You should first instantiate it with MOI.instantiate

[odow]

To clarify:

constructor = MOI.OptimizerWithAttributes(KNITRO.Optimizer, "algoritm"=> KNITRO.KN_ALG_BAR_DIRECT)
model = MOI.instantiate(constructor)

In future, please post usage questions like this on the community forum: https://discourse.julialang.org/c/domain/opt/13

[xinkai-zhou]

I see, thank you both for clarifying!