Roots for Fun with Int coeffs (#73)

* roots for Fun with Int coeffs

* version bump to v0.5.9

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFunOrthogonalPolynomials"
 uuid = "b70543e2-c0d9-56b8-a290-0d4d6d4de211"
-version = "0.5.8"
+version = "0.5.9"
 
 [deps]
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"

src/roots.jl

@@ -63,7 +63,12 @@ function roots(f::Fun)
     end
 end
 
-roots(f::Fun{<:Chebyshev}) = fromcanonical.(f,roots(setcanonicaldomain(f)))
+function roots(f::Fun{<:Chebyshev})
+    g = Fun(space(f), float.(coefficients(f)))
+    gg = setcanonicaldomain(g)
+    r = roots(gg)
+    fromcanonical.(f,r)
+end
 
 
 for (BF,FF) in ((BigFloat,Float64),(Complex{BigFloat},ComplexF64))

test/ChebyshevTest.jl

@@ -136,6 +136,9 @@ import ApproxFunOrthogonalPolynomials: forwardrecurrence
 
         @test_throws ArgumentError roots(Fun(zero))
         @test_throws ArgumentError roots(Fun(Chebyshev(),Float64[]))
+
+        f = Fun(Chebyshev(), [1,2,3])
+        @test sort(roots(f)) ≈ 1/6*[-1-√13, -1+√13]
     end
 
     @testset "Aliasing" begin