Conversions from Polynomials.ChebyshevT (#305)

* Conversions from Polynomials.ChebyshevT

* Conversion from Fun to ChebyshevT

Author: jishnub

Project.toml

@@ -15,15 +15,18 @@ HalfIntegers = "f0d1745a-41c9-11e9-1dd9-e5d34d218721"
 IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 OddEvenIntegers = "8d37c425-f37a-4ca2-9b9d-a61bc06559d2"
+Polynomials = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 Static = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
 [weakdeps]
+Polynomials = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 Static = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
 
 [extensions]
+ApproxFunOrthogonalPolynomialsPolynomialsExt = "Polynomials"
 ApproxFunOrthogonalPolynomialsStaticExt = "Static"
 
 [compat]
@@ -42,6 +45,7 @@ HalfIntegers = "1.5"
 IntervalSets = "0.5, 0.6, 0.7"
 LazyArrays = "0.22, 1"
 OddEvenIntegers = "0.1.8"
+Polynomials = "2, 3, 4"
 Reexport = "0.2, 1"
 SpecialFunctions = "0.10, 1.0, 2"
 Static = "0.8"
@@ -53,9 +57,10 @@ ApproxFunBaseTest = "a931bfaf-0cfd-4a5c-b69c-bf2eed002b43"
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 DualNumbers = "fa6b7ba4-c1ee-5f82-b5fc-ecf0adba8f74"
 LazyArrays = "5078a376-72f3-5289-bfd5-ec5146d43c02"
+Polynomials = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 Static = "aedffcd0-7271-4cad-89d0-dc628f76c6d3"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["ApproxFunBaseTest", "Aqua", "DualNumbers", "Test", "Static", "StaticArrays", "LazyArrays"]
+test = ["ApproxFunBaseTest", "Aqua", "DualNumbers", "Test", "Static", "StaticArrays", "LazyArrays", "Polynomials"]

ext/ApproxFunOrthogonalPolynomialsPolynomialsExt.jl

@@ -0,0 +1,13 @@
+module ApproxFunOrthogonalPolynomialsPolynomialsExt
+
+using ApproxFunOrthogonalPolynomials
+import Polynomials
+import ApproxFunBase: Fun
+
+Fun(C::Polynomials.ChebyshevT, s::Chebyshev{<:ChebyshevInterval}) =
+	Fun(s, float.(Polynomials.coeffs(C)))
+
+Polynomials.ChebyshevT(f::Fun{<:Chebyshev{<:ChebyshevInterval}}) =
+	Polynomials.ChebyshevT(copy(coefficients(f)))
+
+end

src/ApproxFunOrthogonalPolynomials.jl

@@ -183,6 +183,7 @@ include("show.jl")
 
 if !isdefined(Base, :get_extension)
     include("../ext/ApproxFunOrthogonalPolynomialsStaticExt.jl")
+    include("../ext/ApproxFunOrthogonalPolynomialsPolynomialsExt.jl")
 end
 
 end

test/ChebyshevTest.jl

@@ -8,6 +8,7 @@ using Test
 using ApproxFunBase: transform!, itransform!
 using ApproxFunBaseTest: testspace
 using ApproxFunOrthogonalPolynomials: forwardrecurrence
+import Polynomials 
 
 include("testutils.jl")
 
@@ -482,6 +483,15 @@ include("testutils.jl")
 
         @test normalizedspace(NS) == NS
     end
+
+    @testset "Polynomials" begin
+        C = Polynomials.ChebyshevT(Float64[1,2,3])
+        f = Fun(C, Chebyshev())
+        @test Polynomials.coeffs(C) == coefficients(f)
+        @test C(0.2) ≈ f(0.2)
+        C2 = Polynomials.ChebyshevT(f)
+        @test C == C2
+    end
 end
 
 end # module