[Bridges] fix print_active_bridges for some constrained variable cases

src/Bridges/debug.jl

@@ -542,7 +542,9 @@ Print the set of bridges that are active in the model `b`.
 """
 function print_active_bridges(io::IO, b::MOI.Bridges.LazyBridgeOptimizer)
     F = MOI.get(b, MOI.ObjectiveFunctionType())
-    print_active_bridges(io, b, F)
+    if F !== nothing
+        print_active_bridges(io, b, F)
+    end
     types = MOI.get(b, MOI.ListOfConstraintTypesPresent())
     # We add a sort here to make the order reproducible, and to group similar
     # constraints together.
@@ -639,6 +641,11 @@ function print_active_bridges(
     offset::String = "",
 ) where {F<:MOI.AbstractFunction,S<:MOI.AbstractSet}
     if !MOI.supports_constraint(b, F, S)
+        if F == MOI.VariableIndex || F == MOI.VectorOfVariables
+            # Okay. If you don't support the constraint, maybe you support
+            # adding as a constrained variable.
+            return print_active_bridges(io, b, S, offset)
+        end
         throw(
             MOI.UnsupportedConstraint{F,S}(
                 "The constraint cannot be bridged using the set of available " *
@@ -651,35 +658,31 @@ function print_active_bridges(
         _print_supported(io, "Supported constraint: $F-in-$S\n")
         return
     end
-    is_constraint_bridged = true
     c_node = b.constraint_node[(F, S)]
     if F == MOI.VariableIndex || F == MOI.VectorOfVariables
-        # Call `MOI.supports_` here to build the necessary nodes in the bridging
-        # graph.
-        if F == MOI.VariableIndex
-            MOI.supports_add_constrained_variable(b, S)
+        if is_bridged(b, S)
+            # The constraint can be both variable bridged and constraint
+            # bridged. Which is cheaper?
+            v_node = b.variable_node[(S,)]
+            if bridging_cost(b.graph, v_node) <= bridging_cost(b.graph, c_node)
+                return print_active_bridges(io, b, S, offset)
+            end
         else
-            MOI.supports_add_constrained_variables(b, S)
+            # The constraint is bridged via add_constraint, and not via
+            # add_constrained_variable(s).
+            return print_active_bridges(io, b, S, offset)
         end
-        v_node = b.variable_node[(S,)]
-        if bridging_cost(b.graph, v_node) <= bridging_cost(b.graph, c_node)
-            is_constraint_bridged = false
-        end
-    end
-    if is_constraint_bridged
-        index = MOI.Bridges.bridge_index(b.graph, c_node)
-        B = b.constraint_bridge_types[index]
-        BT = MOI.Bridges.Constraint.concrete_bridge_type(B, F, S)
-        print(io, offset, " * ")
-        _print_unsupported(io, "Unsupported constraint: $F-in-$S\n")
-        println(io, offset, " |  bridged by:")
-        print(io, offset, " |   ")
-        MOI.Utilities.print_with_acronym(io, "$BT\n")
-        println(io, offset, " |  may introduce:")
-        _print_bridge(io, b, BT, offset)
-    else
-        print_active_bridges(io, b, S, offset)
     end
+    index = MOI.Bridges.bridge_index(b.graph, c_node)
+    B = b.constraint_bridge_types[index]
+    BT = MOI.Bridges.Constraint.concrete_bridge_type(B, F, S)
+    print(io, offset, " * ")
+    _print_unsupported(io, "Unsupported constraint: $F-in-$S\n")
+    println(io, offset, " |  bridged by:")
+    print(io, offset, " |   ")
+    MOI.Utilities.print_with_acronym(io, "$BT\n")
+    println(io, offset, " |  may introduce:")
+    _print_bridge(io, b, BT, offset)
     return
 end
 

test/Bridges/General/test_debug.jl

@@ -322,6 +322,116 @@ function test_print_graph_stdout()
     return
 end
 
+struct ModelPOIIssue201{T} <: MOI.ModelLike
+    supports_equal_to::Bool
+    supports_parameter::Bool
+    parameter::Vector{T}
+    equal_to::Vector{T}
+    function ModelPOIIssue201{T}(;
+        supports_equal_to::Bool = true,
+        supports_parameter::Bool = true,
+    ) where {T}
+        return new{T}(supports_equal_to, supports_parameter, T[], T[])
+    end
+end
+
+function MOI.supports_add_constrained_variable(
+    model::ModelPOIIssue201{T},
+    ::Type{MOI.Parameter{T}},
+) where {T}
+    return model.supports_parameter
+end
+
+function MOI.supports_add_constrained_variable(
+    model::ModelPOIIssue201{T},
+    ::Type{MOI.EqualTo{T}},
+) where {T}
+    return model.supports_equal_to
+end
+
+function MOI.supports_constraint(
+    model::ModelPOIIssue201{T},
+    ::Type{MOI.ScalarAffineFunction{T}},
+    ::Type{MOI.EqualTo{T}},
+) where {T}
+    return model.supports_equal_to
+end
+
+MOI.get(::ModelPOIIssue201, ::MOI.ObjectiveFunctionType) = nothing
+
+function MOI.get(
+    model::ModelPOIIssue201{T},
+    ::MOI.ListOfConstraintTypesPresent,
+) where {T}
+    ret = Tuple{Type,Type}[]
+    if !isempty(model.parameter)
+        push!(ret, (MOI.VariableIndex, MOI.Parameter{T}))
+    end
+    if !isempty(model.equal_to)
+        push!(ret, (MOI.VariableIndex, MOI.EqualTo{T}))
+    end
+    return ret
+end
+
+function MOI.get(
+    model::ModelPOIIssue201{T},
+    ::MOI.NumberOfConstraints{MOI.VariableIndex,MOI.Parameter{T}},
+) where {T}
+    return length(model.parameter)
+end
+
+function MOI.get(
+    model::ModelPOIIssue201{T},
+    ::MOI.NumberOfConstraints{MOI.VariableIndex,MOI.EqualTo{T}},
+) where {T}
+    return length(model.equal_to)
+end
+
+function MOI.add_constrained_variable(
+    model::ModelPOIIssue201{T},
+    set::MOI.Parameter{T},
+) where {T}
+    push!(model.parameter, set.value)
+    x = MOI.VariableIndex(length(model.parameter))
+    return x, MOI.ConstraintIndex{MOI.VariableIndex,typeof(set)}(x.value)
+end
+
+function MOI.add_constrained_variable(
+    model::ModelPOIIssue201{T},
+    set::MOI.EqualTo{T},
+) where {T}
+    push!(model.equal_to, set.value)
+    x = MOI.VariableIndex(length(model.equal_to))
+    return x, MOI.ConstraintIndex{MOI.VariableIndex,typeof(set)}(x.value)
+end
+
+function test_parametricoptinterface_issue_201_case_1()
+    model = ModelPOIIssue201{Float64}(; supports_equal_to = false)
+    model = MOI.Bridges.full_bridge_optimizer(model, Float64)
+    p, _ = MOI.add_constrained_variable(model, MOI.Parameter(1.0))
+    @test sprint(MOI.Bridges.print_active_bridges, model) ==
+          " * Supported variable: MOI.Parameter{Float64}\n"
+    return
+end
+
+function test_parametricoptinterface_issue_201_case_2()
+    model = ModelPOIIssue201{Float64}(; supports_equal_to = true)
+    model = MOI.Bridges.full_bridge_optimizer(model, Float64)
+    p, _ = MOI.add_constrained_variable(model, MOI.Parameter(1.0))
+    @test sprint(MOI.Bridges.print_active_bridges, model) ==
+          " * Supported variable: MOI.Parameter{Float64}\n"
+    return
+end
+
+function test_parametricoptinterface_issue_201_case_3()
+    model = ModelPOIIssue201{Float64}(; supports_parameter = false)
+    model = MOI.Bridges.full_bridge_optimizer(model, Float64)
+    p, _ = MOI.add_constrained_variable(model, MOI.Parameter(1.0))
+    @test sprint(MOI.Bridges.print_active_bridges, model) ==
+          " * Unsupported variable: MOI.Parameter{Float64}\n |  bridged by:\n |    MOIB.Variable.ParameterToEqualToBridge{Float64}\n |  may introduce:\n |   * Supported variable: MOI.EqualTo{Float64}\n"
+    return
+end
+
 end
 
 TestBridgesDebug.runtests()