Refactor Constraint

Author: blegat

src/constraints/PositiveSemidefiniteConeConstraint.jl

@@ -1,14 +1,9 @@
-mutable struct PositiveSemidefiniteConeConstraint <: Constraint
-    child::AbstractExpr
-    size::Tuple{Int,Int}
-    dual::Union{Value,Nothing}
-
-    function PositiveSemidefiniteConeConstraint(child::AbstractExpr)
-        if child.size[1] != child.size[2]
-            error("Positive semidefinite expressions must be square")
-        end
-        return new(child, child.size, nothing)
+const PositiveSemidefiniteConeConstraint = Constraint{MOI.PositiveSemidefiniteConeTriangle}
+function set_with_size(::Type{MOI.PositiveSemidefiniteConeTriangle}, sz::Tuple{Int,Int})
+    if sz[1] != sz[2]
+        error("Positive semidefinite expressions must be square")
     end
+    return MOI.PositiveSemidefiniteConeTriangle(sz[1])
 end
 
 head(io::IO, ::PositiveSemidefiniteConeConstraint) = print(io, "sdp")

src/constraints/SecondOrderConeConstraint.jl

@@ -1,8 +1,7 @@
-mutable struct SecondOrderConeConstraint <: Constraint
-    children::Tuple
-    dual::Union{Value,Nothing}
+const SecondOrderConeConstraint = Constraint{MOI.SecondOrderCone}
 
-    SecondOrderConeConstraint(args::AbstractExpr...) = new(args, nothing)
+function set_with_size(::Type{MOI.SecondOrderCone}, sz::Tuple{Int})
+    return MOI.SecondOrderCone(sz[1])
 end
 
 head(io::IO, ::SecondOrderConeConstraint) = print(io, "soc")

src/expressions.jl

@@ -28,7 +28,17 @@
 
 abstract type AbstractExpr end
 
-abstract type Constraint end
+struct Constraint{S<:MOI.AbstractSet}
+    child::AbstractExpr
+    set::S
+    dual::ValueOrNothing
+    function Constraint(child, set::MOI.AbstractSet)
+        return new{typeof(set)}(child, set)
+    end
+    function Constraint{S}(child) where {S<:MOI.AbstractSet}
+        return Constraint(child, set_with_size(S, size(child)))
+    end
+end
 
 const Value = Union{Number,AbstractArray}