Change the default mode of CachingOptimizer

docs/src/submodules/Utilities/overview.md

@@ -152,7 +152,7 @@ julia> model = MOI.Utilities.CachingOptimizer(
            PathOptimizer{Float64}(),
        )
 MOIU.CachingOptimizer{MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}},MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}}
-in state ATTACHED_OPTIMIZER
+in state EMPTY_OPTIMIZER
 in mode AUTOMATIC
 with model cache MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}
 with optimizer MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}}
@@ -169,33 +169,34 @@ A [`Utilities.CachingOptimizer`](@ref) may be in one of three possible states:
   optimizer. If the optimizer does not support modifications, and error will be
   thrown.
 
-Use [`Utilities.reset_optimizer`](@ref) to go from `ATTACHED_OPTIMIZER` to
-`EMPTY_OPTIMIZER`:
+Use [`Utilities.attach_optimizer`](@ref) to go from `EMPTY_OPTIMIZER` to
+`ATTACHED_OPTIMIZER`:
 ```jldoctest pathoptimizer
-julia> MOI.Utilities.reset_optimizer(model)
+julia> MOI.Utilities.attach_optimizer(model)
 
 julia> model
 MOIU.CachingOptimizer{MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}},MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}}
-in state EMPTY_OPTIMIZER
+in state ATTACHED_OPTIMIZER
 in mode AUTOMATIC
 with model cache MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}
 with optimizer MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}}
 ```
 
-Use [`Utilities.attach_optimizer`](@ref) to go from `EMPTY_OPTIMIZER` to
-`ATTACHED_OPTIMIZER`:
+!!! info
+    You must be in `ATTACHED_OPTIMIZER` to use [`optimize!`](@ref).
+
+Use [`Utilities.reset_optimizer`](@ref) to go from `ATTACHED_OPTIMIZER` to
+`EMPTY_OPTIMIZER`:
 ```jldoctest pathoptimizer
-julia> MOI.Utilities.attach_optimizer(model)
+julia> MOI.Utilities.reset_optimizer(model)
 
 julia> model
 MOIU.CachingOptimizer{MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}},MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}}
-in state ATTACHED_OPTIMIZER
+in state EMPTY_OPTIMIZER
 in mode AUTOMATIC
 with model cache MOIU.GenericModel{Float64,MOIU.ModelFunctionConstraints{Float64}}
 with optimizer MOIU.GenericOptimizer{Float64,MOIU.VectorOfConstraints{MOI.VectorAffineFunction{Float64},MOI.Complements}}
 ```
-!!! info
-    You must be in `ATTACHED_OPTIMIZER` to use [`optimize!`](@ref).
 
 Use [`Utilities.drop_optimizer`](@ref) to go from any state to `NO_OPTIMIZER`:
 ```jldoctest pathoptimizer

src/Utilities/cachingoptimizer.jl

@@ -70,9 +70,9 @@ end
 """
     CachingOptimizer(model_cache::MOI.ModelLike, optimizer::AbstractOptimizer)
 
-Creates an `CachingOptimizer` in `AUTOMATIC` mode, with the optimizer `optimizer`.
-The `model_cache` manager returned behaves like an `AbstractOptimizer` as long as no
-`CachingOptimizer`-specific functions (e.g. `reset_optimizer`) are called on it.
+Creates an `CachingOptimizer` in `AUTOMATIC` mode, with the optimizer
+`optimizer`.
+
 The type of the optimizer returned is `CachingOptimizer{typeof(optimizer),
 typeof(model_cache)}` so it does not support the function
 `reset_optimizer(::CachingOptimizer, new_optimizer)` if the type of
@@ -87,7 +87,7 @@ function CachingOptimizer(
     return CachingOptimizer{typeof(optimizer),typeof(model_cache)}(
         optimizer,
         model_cache,
-        ATTACHED_OPTIMIZER,
+        EMPTY_OPTIMIZER,
         AUTOMATIC,
         IndexMap(),
         IndexMap(),
@@ -233,9 +233,6 @@ function MOI.empty!(m::CachingOptimizer)
     if m.state == ATTACHED_OPTIMIZER
         MOI.empty!(m.optimizer)
     end
-    if m.state == EMPTY_OPTIMIZER && m.mode == AUTOMATIC
-        m.state = ATTACHED_OPTIMIZER
-    end
     m.model_to_optimizer_map = IndexMap()
     return m.optimizer_to_model_map = IndexMap()
 end

test/Utilities/cachingoptimizer.jl

@@ -118,6 +118,7 @@ struct DummyConstraintAttribute <: MOI.AbstractConstraintAttribute end
         MOIU.UniversalFallback(MOIU.Model{Float64}()),
         mock,
     )
+    MOIU.attach_optimizer(model)
     x = MOI.add_variable(model)
     y = first(MOI.get(mock, MOI.ListOfVariableIndices()))
     @test x != y # Otherwise, these tests will trivially pass
@@ -441,7 +442,7 @@ end
         s.add_con_allowed = true
         @test MOIU.state(m) == MOIU.EMPTY_OPTIMIZER
         MOI.empty!(m)
-        @test MOIU.state(m) == MOIU.ATTACHED_OPTIMIZER
+        @test MOIU.state(m) == MOIU.EMPTY_OPTIMIZER
     end
 
     @testset "Add variable not allowed" begin
@@ -494,12 +495,12 @@ end
         m = MOIU.CachingOptimizer(model, s)
         @test m isa MOIU.CachingOptimizer{typeof(s),typeof(model)}
         @test MOI.is_empty(m)
-        @test MOIU.state(m) == MOIU.ATTACHED_OPTIMIZER
+        @test MOIU.state(m) == MOIU.EMPTY_OPTIMIZER
         @test MOIU.mode(m) == MOIU.AUTOMATIC
         @test MOI.get(m, MOI.SolverName()) == "Mock"
         @test sprint(show, m) == MOI.Utilities.replace_acronym("""
         $(MOIU.CachingOptimizer{MOIU.MockOptimizer{MOIU.Model{Float64}},MOIU.Model{Float64}})
-        in state ATTACHED_OPTIMIZER
+        in state EMPTY_OPTIMIZER
         in mode AUTOMATIC
         with model cache $(MOIU.Model{Float64})
         with optimizer $(MOIU.MockOptimizer{MOIU.Model{Float64}})""")