improve copy_with_eltype (#492)

* improve copy_with_eltype

* easier to read means to modify type of tuple

* remove piracy

Author: jverzani

Project.toml

@@ -2,7 +2,7 @@ name = "Polynomials"
 uuid = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 license = "MIT"
 author = "JuliaMath"
-version = "3.2.8"
+version = "3.2.9"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/common.jl

@@ -347,8 +347,9 @@ function truncate!(ps::Dict{Int,T};
 end
 
 truncate!(ps::NTuple; kwargs...) = throw(ArgumentError("`truncate!` not defined."))
-Base.truncate(ps::NTuple{0}; kwargs...) = ps
-function Base.truncate(ps::NTuple{N,T};
+
+_truncate(ps::NTuple{0}; kwargs...) = ps
+function _truncate(ps::NTuple{N,T};
               rtol::Real = Base.rtoldefault(real(T)),
               atol::Real = 0,) where {N,T}
     thresh = norm(ps, Inf) * rtol + atol
@@ -415,8 +416,9 @@ function chop!(ps::Dict{Int,T};
 end
 
 chop!(ps::NTuple; kwargs...) = throw(ArgumentError("chop! not defined"))
-Base.chop(ps::NTuple{0}; kwargs...) = ps
-function Base.chop(ps::NTuple{N,T};
+
+_chop(ps::NTuple{0}; kwargs...) = ps
+function _chop(ps::NTuple{N,T};
               rtol::Real = Base.rtoldefault(real(T)),
               atol::Real = 0,) where {N,T}
     thresh = norm(ps, Inf) * rtol + atol
@@ -530,19 +532,19 @@ function _eltype(P::Type{<:AbstractPolynomial}, p::AbstractPolynomial)
 end
 
 """
-    copy_with_eltype(::Val{T}, [::Val{X}], p::AbstractPolynomial)
+    copy_with_eltype(::Type{T}, [::Val{X}], p::AbstractPolynomial)
 
 Copy polynomial `p` changing the underlying element type and optionally the symbol.
 """
-copy_with_eltype(::Val{T}, ::Val{X}, p::P) where {T, X, S, Y, P <:AbstractPolynomial{S,Y}} =
-    ⟒(P){T, X}(p.coeffs)
-copy_with_eltype(V::Val{T}, p::P) where {T, S, Y, P <:AbstractPolynomial{S,Y}} =
-    copy_with_eltype(V, Val(Y), p)
+copy_with_eltype(::Type{T}, ::Val{X}, p::P) where {T, X, S, Y, P <:AbstractPolynomial{S,Y}} =
+    ⟒(P){T, Symbol(X)}(p.coeffs)
+copy_with_eltype(::Type{T}, p::P) where {T, S, Y, P <:AbstractPolynomial{S,Y}} =
+    copy_with_eltype(T, Val(Y), p)
 # easier to type if performance isn't an issue, but could be dropped
-copy_with_eltype(::Type{T}, X, p::P) where {T, S, Y, P<:AbstractPolynomial{S, Y}} =
-    copy_with_eltype(Val(T), Val(X), p)
-copy_with_eltype(::Type{T}, p::P) where {T, S, X, P<:AbstractPolynomial{S,X}} =
-    copy_with_eltype(Val(T), Val(X), p)
+#copy_with_eltype(::Type{T}, X, p::P) where {T, S, Y, P<:AbstractPolynomial{S, Y}} =
+#    copy_with_eltype(Val(T), Val(X), p)
+#copy_with_eltype(::Type{T}, p::P) where {T, S, X, P<:AbstractPolynomial{S,X}} =
+#    copy_with_eltype(Val(T), Val(X), p)
 
 Base.iszero(p::AbstractPolynomial) = all(iszero, p)
 

src/polynomials/ImmutablePolynomial.jl

@@ -109,8 +109,9 @@ end
 # overrides from common.jl due to  coeffs being non mutable, N in type parameters
 
 Base.copy(p::P) where {P <: ImmutablePolynomial} = P(coeffs(p))
-Base.similar(p::ImmutablePolynomial, args...) =
-    similar(collect(oeffs(p)), args...)
+copy_with_eltype(::Type{T}, ::Val{X}, p::P) where {T, X, S, Y, N, P <:ImmutablePolynomial{S,Y,N}} =
+    ⟒(P){T, Symbol(X),N}(map(T, p.coeffs))
+Base.similar(p::ImmutablePolynomial, args...) = similar(collect(coeffs(p)), args...) # ???
 # degree, isconstant
 degree(p::ImmutablePolynomial{T,X, N}) where {T,X,N} = N - 1 # no trailing zeros
 isconstant(p::ImmutablePolynomial{T,X,N}) where {T,X,N}  = N <= 1
@@ -135,14 +136,14 @@ end
 function Base.chop(p::ImmutablePolynomial{T,X};
               rtol::Real = Base.rtoldefault(real(T)),
                    atol::Real = 0)  where {T,X}
-    ps = chop(p.coeffs; rtol=rtol, atol=atol)
+    ps = _chop(p.coeffs; rtol=rtol, atol=atol)
     return ImmutablePolynomial{T,X}(ps)
 end
 
 function Base.truncate(p::ImmutablePolynomial{T,X};
                   rtol::Real = Base.rtoldefault(real(T)),
                   atol::Real = 0)  where {T,X}
-    ps = truncate(p.coeffs; rtol=rtol, atol=atol)
+    ps = _truncate(p.coeffs; rtol=rtol, atol=atol)
     ImmutablePolynomial{T,X}(ps)
 end
 

src/polynomials/factored_polynomial.jl

@@ -119,7 +119,7 @@ function Base.convert(P::Type{<:FactoredPolynomial}, p::Polynomial{T,X}) where {
     ⟒(P)(coeffs(p), X)
 end
 
-function copy_with_eltype(::Val{T}, ::Val{X}, p::P) where {T, X, S, Y, P<:FactoredPolynomial{S, Y}}
+function copy_with_eltype(::Type{T}, ::Val{X}, p::P) where {T, X, S, Y, P<:FactoredPolynomial{S, Y}}
     d = convert(Dict{T, Int}, p.coeffs)
     FactoredPolynomial{T, X}(d)
 end

test/StandardBasis.jl

@@ -871,11 +871,11 @@ end
         for T in (Float64, Rational)
             xs = [1,2,3]
             p = fromroots(P,xs)
-            @test Polynomials.copy_with_eltype(Val(T), p) == fromroots(P, T.(xs))
-            @test Polynomials.copy_with_eltype(Val(T), Val(:u), p) == fromroots(P, T.(xs); var=:u)
+            @test Polynomials.copy_with_eltype(T, p) == fromroots(P, T.(xs))
+            @test Polynomials.copy_with_eltype(T, Val(:u), p) == fromroots(P, T.(xs); var=:u)
             P == ImmutablePolynomial && continue
-            @inferred Polynomials.copy_with_eltype(Val(T), Val(:u), p)
-            @inferred Polynomials.copy_with_eltype(Val(T), p)
+            @inferred Polynomials.copy_with_eltype(T, Val(:u), p)
+            @inferred Polynomials.copy_with_eltype(T, p)
         end
     end
 end