Merge pull request #3677 from JuliaReach/schillic/rand_hpolytope

`HPolytope`: simplify `rand` in 1D/2D or for 1 vertex

src/Sets/HPolytope/init_LazySets.jl

@@ -1,2 +1,6 @@
+using .LazySets.EmptySetModule: EmptySet
 using .LazySets.HPolygonModule: HPolygon
+using .LazySets.IntervalModule: Interval
+using .LazySets.SingletonModule: Singleton
+using .LazySets.VPolygonModule: VPolygon
 using .LazySets.VPolytopeModule: VPolytope

src/Sets/HPolytope/rand.jl

@@ -30,9 +30,20 @@ function rand(::Type{HPolytope};
               rng::AbstractRNG=GLOBAL_RNG,
               seed::Union{Int,Nothing}=nothing,
               num_vertices::Int=-1)
-    require(@__MODULE__, :Polyhedra; fun_name="rand")
-    rng = reseed!(rng, seed)
-    vpolytope = rand(VPolytope; N=N, dim=dim, rng=rng, seed=seed,
-                     num_vertices=num_vertices)
-    return convert(HPolytope, vpolytope)
+    require(@__MODULE__, :LazySets; fun_name="rand")
+
+    if num_vertices == 1
+        P = rand(Singleton; N=N, dim=dim, rng=rng, seed=seed)
+    elseif dim == 1
+        if num_vertices ∉ (-1, 2)
+            throw(ArgumentError("creating a 1D random polytope is only supported for 2 vertices"))
+        end
+        P = rand(Interval; N=N, dim=dim, rng=rng, seed=seed)
+    elseif dim == 2
+        P = rand(VPolygon; N=N, dim=dim, rng=rng, seed=seed, num_vertices=num_vertices)
+    else
+        rng = reseed!(rng, seed)
+        P = rand(VPolytope; N=N, dim=dim, rng=rng, seed=seed, num_vertices=num_vertices)
+    end
+    return convert(HPolytope, P)
 end

test/Sets/Polytope.jl

@@ -4,11 +4,8 @@ global test_suite_polyhedra
 
 for N in [Float64, Rational{Int}, Float32]
     # random polytopes
-    if test_suite_polyhedra
-        rand(HPolytope)
-    else
-        @test_throws AssertionError rand(HPolytope)
-    end
+    @test_throws ArgumentError rand(HPolytope; N=N, dim=1, num_vertices=3)
+    @test_broken rand(HPolytope; N=N, dim=1, num_vertices=0)
     rand(VPolytope)
 
     # -----
@@ -347,6 +344,22 @@ end
 
 # tests that only work with Float64 and Float32
 for N in [Float64, Float32]
+    # rand
+    @test_broken rand(HPolytope; N=N, dim=2, num_vertices=0)  # TODO fix
+    @test_broken rand(HPolytope; N=N, dim=3, num_vertices=0)  # TODO fix
+    p = rand(HPolytope; N=N, num_vertices=1)
+    @test p isa HPolytope{N} && dim(p) == 2
+    p = rand(HPolytope; N=N, dim=1)
+    @test p isa HPolytope{N} && dim(p) == 1  # TODO fix
+    p = rand(HPolytope; N=N, dim=2)
+    @test p isa HPolytope{N} && dim(p) == 2
+    if test_suite_polyhedra
+        p = rand(HPolytope; N=N, dim=3)
+        @test p isa HPolytope{Float64} && dim(p) == 3
+    else
+        @test_throws AssertionError rand(HPolytope; N=N, dim=3)
+    end
+
     # normalization
     p1 = HPolytope([HalfSpace(N[1e5], N(3e5)), HalfSpace(N[-2e5], N(4e5))])
     p2 = normalize(p1)