convert from AbstractHyperrectangle to Zonotope

JuliaReach · Feb 7, 2018 · 32c8451 · 32c8451
1 parent ab5d2c1
commit 32c8451
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diff --git a/docs/src/lib/representations.md b/docs/src/lib/representations.md
@@ -135,7 +135,7 @@ low(::Hyperrectangle{Float64})
 ```@docs
 LinearConstraint
 Line
-intersection(::Line{Float64}, L2::Line{Float64})
+intersection(::Line{Float64}, ::Line{Float64})
 ```
 
 ## Polygons
@@ -253,9 +253,10 @@ center(::Zonotope{Float64})
 vertices_list(::Zonotope{Float64})
 singleton_list(::Zonotope{Float64})
 order(::Zonotope{Float64})
-minkowski_sum(Z1::Zonotope, Z2::Zonotope)
-linear_map(M::AbstractMatrix, Z::Zonotope)
-scale(α::Real, Z::Zonotope)
-ngens(Z::Zonotope)
-reduce_order(Z::Zonotope{Float64}, r)
+minkowski_sum(::Zonotope, ::Zonotope)
+linear_map(::AbstractMatrix, ::Zonotope)
+scale(::Real, ::Zonotope)
+ngens(::Zonotope)
+reduce_order(::Zonotope{Float64}, r)
+convert(::Type{Zonotope}, ::AbstractHyperrectangle{Float64})
 ```
diff --git a/src/Zonotope.jl b/src/Zonotope.jl
@@ -1,4 +1,5 @@
-import Base.∈
+import Base:∈,
+            convert
 
 export Zonotope,
        order,
@@ -385,3 +386,26 @@ function reduce_order(Z::Zonotope{N}, r)::Zonotope{N} where {N<:Real}
     end
     return Zonotope(c, Gred)
 end
+
+"""
+    convert(::Type{Zonotope}, H::AbstractHyperrectangle{N}) where {N}
+
+Converts a hyperrectangular set to a zonotope.
+
+### Input
+
+- `Zonotope`
+- `H` -- hyperrectangular set
+
+### Output
+
+A zonotope.
+"""
+function convert(::Type{Zonotope}, H::AbstractHyperrectangle{N}) where {N}
+    n = dim(H)
+    gens = zeros(N, n, n)
+    for i in 1:n
+        gens[i, i] = radius_hyperrectangle(H, i)
+    end
+    return Zonotope{N}(center(H), gens)
+end
diff --git a/test/unit_Zonotope.jl b/test/unit_Zonotope.jl
@@ -76,4 +76,8 @@ for N in [Float64, Rational{Int}, Float32]
     Zred2 = reduce_order(Z, 2)
     @test ngens(Zred2) == 4
     @test order(Zred2) == 2
+
+    # test conversion from hyperrectangular sets
+    convert(Zonotope, Hyperrectangle(N[2.,3.], N[4.,5.]))
+    convert(Zonotope, BallInf(N[5.,3.], N(2.)))
 end