Merge pull request #3772 from JuliaReach/schillic/rationalize_universe

`Universe`: fix `rationalize`

Author: schillic

docs/src/lib/sets/Universe.md

@@ -83,6 +83,7 @@ Undocumented implementations:
 * [`∈`](@ref ∈(::AbstractVector, ::LazySet))
 * [`permute`](@ref permute(::LazySet, ::AbstractVector{Int}))
 * [`project`](@ref project(::LazySet, ::AbstractVector{Int}))
+* [`rationalize`](@ref rationalize(::LazySet))
 * [`scale`](@ref scale(::Real, ::LazySet))
 * [`scale!`](@ref scale!(::Real, ::LazySet))
 * [`translate`](@ref translate(::LazySet, ::AbstractVector))
@@ -102,7 +103,6 @@ Inherited from [`LazySet`](@ref):
 * [`eltype`](@ref eltype(::Type{<:LazySet}))
 * [`eltype`](@ref eltype(::LazySet))
 * [`isoperation`](@ref isoperation(::LazySet))
-* [`rationalize`](@ref rationalize(::LazySet))
 * [`rectify`](@ref rectify(::LazySet))
 * [`singleton_list`](@ref singleton_list(::LazySet))
 * [`surface`](@ref surface(::LazySet))

src/Sets/Universe/UniverseModule.jl

@@ -14,7 +14,7 @@ using ReachabilityBase.Require: require
                         reflect, ∈, permute, project, scale, scale!, ρ, σ,
                         translate, translate!, cartesian_product, intersection
 @reexport import ..LazySets: constrained_dimensions, linear_map_inverse,
-                             tosimplehrep
+                             rationalize, tosimplehrep
 import Base: copy
 @reexport using ..API
 
@@ -37,6 +37,7 @@ include("isuniversal.jl")
 include("norm.jl")
 include("radius.jl")
 include("rand.jl")
+include("rationalize.jl")
 include("reflect.jl")
 include("in.jl")
 include("permute.jl")

src/Sets/Universe/rationalize.jl

@@ -0,0 +1,3 @@
+function rationalize(::Type{T}, U::Universe{<:AbstractFloat}, tol::Real) where {T<:Integer}
+    return Universe{Rational{T}}(dim(U))
+end

test/Sets/Universe.jl

@@ -132,5 +132,14 @@ for N in [Float64, Rational{Int}, Float32]
     @test_throws ArgumentError scale!(N(0), U2)
 end
 
+for N in [Float64, Float32]
+    U = Universe{N}(2)
+
+    # rationalize
+    U2 = rationalize(U)
+    @test U2 isa Universe{Rational{Int}} && dim(U2) == 2
+    @test_throws MethodError rationalize(U2)
+end
+
 # default Float64 constructor
 @test Universe(2) == Universe{Float64}(2)