#336 - Revise conversion from HPolytope to HPolygon

src/HPolygonOpt.jl

@@ -44,10 +44,17 @@ HPolygonOpt(constraints::Vector{LinearConstraint{N}},
             ind::Int=1) where {N<:Real} =
     HPolygonOpt{N}(constraints, ind)
 
+# constructor for an HPolygon with no constraints
+HPolygonOpt{N}() where {N<:Real} = HPolygonOpt{N}(Vector{LinearConstraint{N}}(0), 1)
+
+# constructor for an HPolygon with no constraints of type Float64
+HPolygonOpt() = HPolygonOpt{Float64}()
+
 # conversion constructor
 HPolygonOpt(S::LazySet) = convert(HPolygonOpt, S)
 
 
+
 # --- LazySet interface functions ---
 
 

src/convert.jl

@@ -59,11 +59,16 @@ Convert from 2D polytope in H-representation to polygon in H-representation.
 The 2D polytope represented as polygon.
 """
 function convert(::Type{HPOLYGON},
-                 P::HPolytope) where {HPOLYGON<:AbstractHPolygon}
+                 P::HPolytope{N}) where {N, HPOLYGON<:AbstractHPolygon}
     if dim(P) != 2
         error("polytope must be 2D for conversion")
     end
-    return HPOLYGON(P.constraints)
+    H = HPOLYGON{N}()
+    for ci in constraints_list(P)
+        # guarantee that the edges are correctly sorted for storage
+        addconstraint!(H, ci)
+    end
+    return H
 end
 
 """

test/unit_Polygon.jl

@@ -147,5 +147,6 @@ for N in [Float64, Float32, Rational{Int}]
     end
 end
 
-# default Float64 constructor
-HPolygon()
+# default Float64 constructors
+@test HPolygon() isa LazySets.HPolygon{Float64}
+@test HPolygonOpt() isa LazySets.HPolygonOpt{Float64}