Merge pull request #12 from JuliaAlgebra/sexponents

Make SExponents opaque isbits type

src/evaluation.jl

@@ -10,12 +10,12 @@ Evaluate the polynomial `f` at `x`.
 end
 (f::Polynomial)(x::AbstractVector) = evaluate(f, x)
 
-function evaluate_impl(f::Type{Polynomial{T, NVars, E}}) where {T, NVars, E<:SExponents}
+function evaluate_impl(f::Type{Polynomial{T, NVars, E}}) where {T, NVars, E}
     quote
         @boundscheck length(x) ≥ NVars
         c = coefficients(f)
         @inbounds out = begin
-            $(generate_evaluate(exponents(E, NVars), T))
+            $(generate_evaluate(exponents(E), T))
         end
         out
     end
@@ -76,12 +76,12 @@ end
     _val_gradient_impl(f)
 end
 
-function _val_gradient_impl(f::Type{Polynomial{T, NVars, E}}) where {T, NVars, E<:SExponents}
+function _val_gradient_impl(f::Type{Polynomial{T, NVars, E}}) where {T, NVars, E}
     quote
         @boundscheck length(x) ≥ NVars
         c = coefficients(f)
         @inbounds val, grad = begin
-            $(generate_gradient(exponents(E, NVars), T))
+            $(generate_gradient(exponents(E), T))
         end
         val, grad
     end

src/polynomial.jl

@@ -6,18 +6,18 @@ export Polynomial, coefficients, exponents, nvariables, coefficienttype
 
 Construct a Polynomial from `f`.
 """
-struct Polynomial{T, NVars, E<:SExponents}
+struct Polynomial{T, NVars, SE}
     coefficients::Vector{T}
     variables::SVector{NVars, Symbol}
 
-    function Polynomial{T, NVars, SExponents{E}}(coefficients::Vector{T}, variables::SVector{NVars, Symbol}) where {T, NVars, E}
-        @assert length(coefficients) == div(length(E), NVars) "Coefficients size does not match exponents size"
+    function Polynomial{T, NVars, SE}(coefficients::Vector{T}, variables::SVector{NVars, Symbol}) where {T, NVars, SE}
+        @assert length(coefficients) == div(length(SE), NVars) "Coefficients size does not match exponents size"
         new(coefficients, variables)
     end
 end
 
-function Polynomial(coefficients::Vector{T}, nvars, exponents::E, variables) where {T, E<:SExponents}
-    return Polynomial{T, nvars, E}(coefficients, variables)
+function Polynomial(coefficients::Vector{T}, nvars, exponents::SExponents, variables) where {T}
+    return Polynomial{T, nvars, exponents}(coefficients, variables)
 end
 
 function Polynomial(coefficients::Vector{T}, exponents::Matrix{<:Integer}, variables=SVector((Symbol("x", i) for i=1:size(exponents, 1))...)) where {T}
@@ -75,10 +75,12 @@ coefficients(f::Polynomial) = f.coefficients
 Return the exponents of `f` as an matrix where each column represents
 the exponents of a monomial.
 """
-function exponents(::Polynomial{T, NVars, E}) where {T, NVars, E<:SExponents}
-    exponents(E, NVars)
+function exponents(::Polynomial{T, NVars, E}) where {T, NVars, E}
+    exponents(E)
 end
 
+sexponents(::Polynomial{T, NVars, E}) where {T, NVars, E} = E
+
 """
     nvariables(f::Polynomial)
 
@@ -94,6 +96,6 @@ Return the type of the coefficients of `f`.
 coefficienttype(::Polynomial{T, NVars}) where {T, NVars} = T
 
 
-function Base.:(==)(f::Polynomial{T, NVars, E}, g::Polynomial{T, NVars, E}) where {T, NVars, E<:SExponents}
-    coefficients(f) == coefficients(g)
+function Base.:(==)(f::Polynomial{T, NVars, E1}, g::Polynomial{T, NVars, E2}) where {T, NVars, E1, E2}
+    E1 == E2 && coefficients(f) == coefficients(g)
 end

src/sexponents.jl

@@ -1,36 +1,39 @@
 export SExponents
 
-struct SExponents{E}
-    function SExponents{E}() where { E}
-        @assert typeof(E) <: NTuple{N, Int} where N "Exponents type invalid"
-        new()
-    end
+struct SExponents{N}
+    exponents::NTuple{N, UInt8}
+    size::Tuple{Int,Int} # nvars, nterms
 end
 
 function SExponents(exponents::Matrix{<:Integer})
-    # NVars = size(exponents, 1)
-    E = ntuple(i -> convert(Int, exponents[i]), length(exponents))
+    E = ntuple(i -> convert(UInt8, exponents[i]), length(exponents))
+
+    return SExponents(E, size(exponents))
+end
 
-    return SExponents{E}()
+Base.isbits(::Type{<:SExponents}) = true
+Base.length(::SExponents{N}) where N = N
+function Base.:(==)(f::SExponents{N}, g::SExponents{N}) where {N}
+    f.exponents == g.exponents && f.size == g.size
 end
+Base.hash(f::SExponents, h) = hash(f.exponents, hash(f.size, h))
+
 
 """
     exponents(::SExponents)
 
 Converts exponents stored in a `SExponents` to a matrix.
 """
-function exponents(::Type{SExponents{E}}, nvars) where {E}
-    nterms = div(length(E), nvars)
+function exponents(SE::SExponents)
+    nvars, nterms = SE.size
     exps = fill(0, nvars, nterms)
     for k=1:nvars*nterms
-        exps[k] = E[k]
+        exps[k] = SE.exponents[k]
     end
     exps
 end
-exponents(::S, nvars) where {S<:SExponents} = exponents(S, nvars)
 
-function Base.show(io::IO, ::Type{SExponents{E}}) where {E}
-    exps_hash = num2hex(hash(E))
-    print(io, "SExponents{$(exps_hash)}")
+function Base.show(io::IO, SE::SExponents{N}) where {N}
+    exps_hash = num2hex(hash(SE.exponents))
+    print(io, "SExponents{$N}($(exps_hash))")
 end
-Base.show(io::IO, S::SExponents) = print(io, typeof(S), "()")

src/show.jl

@@ -9,7 +9,7 @@ function Base.show(io::IO, p::Polynomial{T, N, E}) where {T,N,E}
     first = true
     cfs = coefficients(p)
 
-    exps = exponents(E, N)
+    exps = exponents(E)
     NVars, NTerms = size(exps)
 
     for j=1:NTerms

src/system.jl

@@ -151,7 +151,7 @@ module Systems
         fs = [Symbol("f", i) for i=1:n]
         Es = [Symbol("E", i) for i=1:n]
         fields = [:($(fs[i])::Polynomial{T, N, $(Symbol("E", i))}) for i=1:n]
-        types = [:($(Es[i])<:SExponents) for i=1:n]
+        types = [:($(Es[i])) for i=1:n]
         name = Symbol("System", n)
         quote
             struct $(name){T, N, $(types...)} <: AbstractSystem{T, $n, N}

test/basic_tests.jl

@@ -1,7 +1,7 @@
 @testset "constructors" begin
     A = round.(Int, max.(0.0, 5 * rand(6, 10) .- 1))
     f = Polynomial(rand(10), A)
-    @test typeof(f) <: Polynomial{Float64, 6, <:SExponents}
+    @test typeof(f) <: Polynomial{Float64, 6}
 
     @test_throws AssertionError Polynomial(rand(9), A)
 

test/runtests.jl

@@ -11,3 +11,13 @@ include("codegen_tests.jl")
 include("basic_tests.jl")
 include("evaluation_tests.jl")
 include("gradient_tests.jl")
+
+A = [1 3 3; 0 2 3]
+
+isbits(SP.SExponents(A))
+
+@polyvar x y
+
+f = Polynomial(x^2+y^2+2y*x-3x^3*y)
+w = rand(2)
+SP.evaluate(f,w)