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[Bridges] maintenance of zero_one.jl #1574

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Merged
merged 2 commits into from
Sep 6, 2021
Merged

[Bridges] maintenance of zero_one.jl #1574

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[Bridges] maintenance of zero_one.jl
odow Sep 3, 2021
599d886
Fixes
odow Sep 3, 2021
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37 changes: 6 additions & 31 deletions src/Bridges/Constraint/zero_one.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -22,14 +22,16 @@ function bridge_constraint(
return ZeroOneBridge{T}(interval_index, integer_index)
end

function MOIB.added_constraint_types(::Type{<:ZeroOneBridge{T}}) where {T}
function MOI.Bridges.added_constraint_types(
::Type{<:ZeroOneBridge{T}},
) where {T}
return Tuple{Type,Type}[
(MOI.VariableIndex, MOI.Interval{T}),
(MOI.VariableIndex, MOI.Integer),
]
end

function MOIB.added_constrained_variable_types(::Type{<:ZeroOneBridge})
function MOI.Bridges.added_constrained_variable_types(::Type{<:ZeroOneBridge})
return Tuple{Type}[]
end

Expand All @@ -49,14 +51,7 @@ function MOI.supports_constraint(
return true
end

# Attributes, Bridge acting as a constraint
function MOI.get(
model::MOI.ModelLike,
attr::MOI.ConstraintSet,
bridge::ZeroOneBridge,
)
return MOI.ZeroOne()
end
MOI.get(::MOI.ModelLike, ::MOI.ConstraintSet, ::ZeroOneBridge) = MOI.ZeroOne()

function MOI.get(
model::MOI.ModelLike,
Expand All @@ -74,32 +69,12 @@ end

function MOI.get(
model::MOI.ModelLike,
attr::Union{MOI.ConstraintPrimal,MOI.ConstraintPrimalStart},
attr::Union{MOI.ConstraintPrimal},
bridge::ZeroOneBridge,
)
return MOI.get(model, attr, bridge.interval_index)
end

function MOI.supports(
::MOI.ModelLike,
::MOI.ConstraintPrimalStart,
::Type{<:ZeroOneBridge},
)
return true
end

function MOI.set(
model::MOI.ModelLike,
attr::MOI.ConstraintPrimalStart,
bridge::ZeroOneBridge{T},
value,
) where {T}
MOI.set(model, attr, bridge.integer_index, value)
MOI.set(model, attr, bridge.interval_index, value)
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@blegat does ConstraintPrimalStart make sense for a ZeroOne constraint?

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Yes, a ConstraintPrimalStart is the starting value of the function. It's well-defined for all constraints

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Sure. But does any solver actually implement it...

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Since most solvers only support VariableIndex-in-Integer, and setting the starting value of this is a bit redundant, I don't think so. However, if a solver want to implemented ScalarAffineFunction in Integer, they will need this.

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@odow odow Sep 5, 2021 •
edited
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To rephrase: in what situation would a solver benefit from being able to set ConstraintPrimalStart of a ZeroOne constraint.

There's a lot of stuff in MOI that is there "just because" without a good reason. Not that we shouldn't add some of the stuff. But if no one is ever going to call it, we shouldn't rush to add code. It's an overhead for everyone.

return
end

# Attributes, Bridge acting as a model
function MOI.get(
::ZeroOneBridge{T},
::MOI.NumberOfConstraints{MOI.VariableIndex,MOI.Interval{T}},
Expand Down
8 changes: 0 additions & 8 deletions test/Bridges/Constraint/zero_one.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -32,8 +32,6 @@ function test_ZeroOne()
MOI.VariableIndex,
MOI.ZeroOne,
) == bridge_type

@test MOI.supports(bridged_mock, MOI.ConstraintPrimalStart(), bridge_type)
MOI.Test.test_basic_VariableIndex_ZeroOne(bridged_mock, config)
MOI.empty!(bridged_mock)
MOI.Utilities.set_mock_optimize!(
Expand Down Expand Up @@ -81,12 +79,6 @@ function test_ZeroOne()
MOI.ListOfConstraintIndices{MOI.VariableIndex,MOI.ZeroOne}(),
),
)
for attr in [MOI.ConstraintPrimalStart()]
@test MOI.supports(bridged_mock, attr, typeof(ci))
value = 1.0
MOI.set(bridged_mock, attr, ci, value)
@test MOI.get(bridged_mock, attr, ci) ≈ value
end
s = """
variables: x, y
y == 1.0
Expand Down