change default convert from zonotope to SPZ

Author: schillic

docs/src/lib/conversion.md

@@ -39,7 +39,7 @@ convert(::Type{MinkowskiSumArray}, ::MinkowskiSum{N, ST, MinkowskiSumArray{N, ST
 convert(::Type{STAR}, ::AbstractPolyhedron{N}) where {N}
 convert(::Type{STAR}, ::Star)
 convert(::Type{SimpleSparsePolynomialZonotope}, ::AbstractZonotope)
-convert(::Type{SparsePolynomialZonotope}, ::AbstractZonotope{N}) where {N}
+convert(::Type{SparsePolynomialZonotope}, ::AbstractZonotope)
 convert(::Type{SparsePolynomialZonotope}, ::SimpleSparsePolynomialZonotope{N}) where {N}
 ```
 

src/Convert/SparsePolynomialZonotope.jl

@@ -1,22 +1,36 @@
 """
-    convert(::Type{SparsePolynomialZonotope}, Z::AbstractZonotope{N}) where {N}
+    convert(::Type{SparsePolynomialZonotope}, Z::AbstractZonotope; [algorithm]="GI")
 
 Convert a zonotope to sparse polynomial zonotope.
 
 ### Input
 
 - `SparsePolynomialZonotope` -- target type
 - `Z`                        -- zonotopic set
+- `algorithm`                -- (optional, default: `"GI"`) algorithm
 
 ### Output
 
 A sparse polynomial zonotope.
 
 ### Algorithm
 
-The method implements [Kochdumper21a; Proposition 3.1.19](@citet).
+The `"GI"` method creates a polynomial zonotope with only independent generators.
+
+The `"K21"` method creates a polynomial zonotope with only dependent generators,
+implementing [Kochdumper21a; Proposition 3.1.9](@citet).
 """
-function convert(::Type{SparsePolynomialZonotope}, Z::AbstractZonotope{N}) where {N}
+function convert(::Type{SparsePolynomialZonotope}, Z::AbstractZonotope;
+                 algorithm="GI")
+    if algorithm == "GI"
+        return _convert_SPZ_Z_GI(Z)
+    elseif algorithm == "K21"
+        return _convert_SPZ_Z_K21(Z)
+    end
+    throw(ArgumentError("invalid algorithm $algorithm"))
+end
+
+function _convert_SPZ_Z_K21(Z::AbstractZonotope{N}) where {N}
     c = center(Z)
     G = genmat(Z)
     p = ngens(Z)
@@ -25,6 +39,14 @@ function convert(::Type{SparsePolynomialZonotope}, Z::AbstractZonotope{N}) where
     return SparsePolynomialZonotope(c, G, GI, E)
 end
 
+function _convert_SPZ_Z_GI(Z::AbstractZonotope{N}) where {N}
+    c = center(Z)
+    GI = genmat(Z)
+    E = zeros(Int, 0, 0)
+    G = zeros(N, length(c), 0)
+    return SparsePolynomialZonotope(c, G, GI, E)
+end
+
 """
     convert(::Type{SparsePolynomialZonotope}, SSPZ::SimpleSparsePolynomialZonotope)
 

test/ConcreteOperations/minkowski_sum.jl

@@ -23,18 +23,21 @@ for N in @tN([Float64, Float32, Rational{Int}])
     H2 = Hyperrectangle(N[5, 6], N[7, 8])
     @test minkowski_sum(H1, H2) == Hyperrectangle(N[6, 8], N[10, 12])
     SPZ = convert(SparsePolynomialZonotope, H1)
-    for P in (SPZ, convert(SSPZ, SPZ))
-        P = minkowski_sum(P, H2)
-        # equality is not required but approximates the equivalence check
-        @test P == SparsePolynomialZonotope(N[6, 8], N[3 0; 0 4], N[7 0; 0 8], [1 0; 0 1], 1:2)
-        P = minkowski_sum(H1, convert(SparsePolynomialZonotope, H2))
-        @test P == SparsePolynomialZonotope(N[6, 8], N[7 0; 0 8], N[3 0; 0 4], [1 0; 0 1], 1:2)
-    end
-
-    P = SparsePolynomialZonotope(N[1, -1], N[1 1; 0 -1], N[1 0; 0 -1], [2 1; 0 1; 1 0], [3, 4, 5])
-    Z = Zonotope(N[0, 1], N[2 1; 1 -1])
-    ms = minkowski_sum(P, Z)
-    @test indexvector(ms) == indexvector(P)
+    # SPZ + Z
+    P = SPZ
+    P2 = minkowski_sum(P, H2)
+    @test indexvector(P2) == indexvector(SPZ)
+    # equality is not required but approximates the equivalence check
+    @test P2 == SparsePolynomialZonotope(N[6, 8], zeros(N, 2, 0), N[3 0 7 0; 0 4 0 8], zeros(Int, 0, 0), Int[])
+    P2 = minkowski_sum(H1, convert(SparsePolynomialZonotope, H2))
+    @test P2 == SparsePolynomialZonotope(N[6, 8], zeros(N, 2, 0), N[7 0 3 0; 0 8 0 4], zeros(Int, 0, 0), Int[])
+    # SSPZ + Z
+    P = convert(SSPZ, SPZ)
+    P2 = minkowski_sum(P, H2)
+    # equality is not required but approximates the equivalence check
+    @test P2 == SparsePolynomialZonotope(N[6, 8], N[3 0; 0 4], N[7 0; 0 8], [1 0; 0 1], 1:2)
+    P2 = minkowski_sum(H1, convert(SparsePolynomialZonotope, H2))
+    @test P2 == SparsePolynomialZonotope(N[6, 8], zeros(N, 2, 0), N[7 0 3 0; 0 8 0 4], zeros(Int, 0, 0), Int[])
 end
 
 for N in @tN([Float64, Float32])

test/Sets/SparsePolynomialZonotope.jl

@@ -259,7 +259,13 @@ for N in @tN([Float64, Float32])
 end
 
 for Z in [rand(Zonotope), rand(Hyperrectangle)]
-    ZS = convert(SparsePolynomialZonotope, Z)
+    ZS = convert(SparsePolynomialZonotope, Z; algorithm="GI")
+    @test center(ZS) == center(Z)
+    @test isempty(genmat_dep(ZS))
+    @test genmat_indep(ZS) == genmat(Z)
+    @test isempty(expmat(ZS))
+
+    ZS = convert(SparsePolynomialZonotope, Z; algorithm="K21")
     @test center(ZS) == center(Z)
     @test genmat_dep(ZS) == genmat(Z)
     @test isempty(genmat_indep(ZS))