vertices list for degenerate interval (#2459)

JuliaReach · Dec 22, 2020 · 7a12227 · 7a12227
1 parent 625a20b
commit 7a12227
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diff --git a/src/Sets/Interval.jl b/src/Sets/Interval.jl
@@ -384,10 +384,13 @@ Return the list of vertices of this interval.
 
 ### Output
 
-The list of vertices of the interval represented as two one-dimensional vectors.
+The list of vertices of the interval represented as two one-dimensional vectors,
+or just one if the interval is degenerate (the endpoints match within the tolerance).
 """
 function vertices_list(x::Interval)
-    return [[min(x)], [max(x)]]
+    a = min(x)
+    b = max(x)
+    return _isapprox(a, b) ? [[a]] : [[a], [b]]
 end
 
 """

diff --git a/test/unit_Interval.jl b/test/unit_Interval.jl
@@ -29,6 +29,10 @@ for N in Ns
     @test min(x) == N(0) && max(x) == N(1)
     v = vertices_list(x)
     @test N[0] in v && N[1] in v
+
+    # vertices list for degenerate interval
+    @test vertices_list(Interval(N(0), N(0))) == [[N(0)]]
+
     # test interface method an_element and membership
     @test an_element(x) ∈ x
     # test containment