first/last return floats for Int coefficients (#277)

* first/last return floats for Int coefficients

* remove Ultraspherical specializations

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFunOrthogonalPolynomials"
 uuid = "b70543e2-c0d9-56b8-a290-0d4d6d4de211"
-version = "0.6.38"
+version = "0.6.39"
 
 [deps]
 ApproxFunBase = "fbd15aa5-315a-5a7d-a8a4-24992e37be05"

src/Spaces/Chebyshev/Chebyshev.jl

@@ -59,12 +59,18 @@ ones(S::Chebyshev) = Fun(S,fill(1.0,1))
 
 function first(f::Fun{<:Chebyshev})
     n = ncoefficients(f)
-    n == 0 && return zero(cfstype(f))
-    n == 1 && return f.coefficients[1]
-    foldr(-,coefficients(f))
+    T = rangetype(space(f))
+    oneel = oneunit(T)
+    n == 0 && return zero(cfstype(f)) * oneel
+    n == 1 && return f.coefficients[1] * oneel
+    foldr(-,coefficients(f)) * oneel
 end
 
-last(f::Fun{<:Chebyshev}) = reduce(+,coefficients(f))
+function last(f::Fun{<:Chebyshev})
+    T = rangetype(space(f))
+    oneel = oneunit(T)
+    reduce(+,coefficients(f)) * oneel
+end
 
 spacescompatible(a::Chebyshev,b::Chebyshev) = domainscompatible(a,b)
 hasfasttransform(::Chebyshev) = true

src/Spaces/Ultraspherical/Ultraspherical.jl

@@ -100,21 +100,6 @@ ones(::Type{T},S::Ultraspherical) where {T<:Number} = Fun(S,fill(one(T),1))
 ones(S::Ultraspherical) = ones(Float64, S)
 
 
-
-## Fast evaluation
-
-function first(f::Fun{<:Ultraspherical{Int}})
-    n = length(f.coefficients)
-    n == 0 && return zero(cfstype(f))
-    n == 1 && return first(f.coefficients)
-    foldr(-,coefficients(f,Chebyshev))
-end
-
-last(f::Fun{<:Ultraspherical{Int}}) = reduce(+,coefficients(f,Chebyshev))
-
-first(f::Fun{<:Ultraspherical}) = f(leftendpoint(domain(f)))
-last(f::Fun{<:Ultraspherical}) = f(rightendpoint(domain(f)))
-
 function Fun(::typeof(identity), s::Ultraspherical)
     d = domain(s)
     m = order(s)

test/ChebyshevTest.jl

@@ -56,6 +56,12 @@ include("testutils.jl")
         @test contains(summary(p), "ShiftedChebyshevGrid{Float64}")
     end
 
+    @testset "first/last" begin
+        f = Fun(Chebyshev(), [1,2])
+        @test @inferred(first(f)) === f(-1)
+        @test @inferred(last(f)) === f(1)
+    end
+
     @testset "inference in Space(::Interval)" begin
         S = @inferred Space(0..1)
         f = Fun(S)

test/UltrasphericalTest.jl

@@ -27,6 +27,11 @@ include("testutils.jl")
             @test f(xm) ≈ xm
         end
     end
+    @testset "first/last" begin
+        f = Fun(Ultraspherical(2), [1,2])
+        @test @inferred(first(f)) === f(-1)
+        @test @inferred(last(f)) === f(1)
+    end
     @testset "Conversion" begin
         # Tests whether invalid/unimplemented arguments correctly throws ArgumentError
         @test_throws ArgumentError Conversion(Ultraspherical(2), Ultraspherical(1))