Merge pull request #63 from JuliaMath/test

Small dispatch fix for gamma

Author: heltonmc

src/gamma.jl

@@ -1,6 +1,6 @@
 # Adapted from Cephes Mathematical Library (MIT license https://en.smath.com/view/CephesMathLibrary/license) by Stephen L. Moshier
-gamma(z::Number) = _gamma(float(z))
-_gamma(x::Float32) = Float32(_gamma(Float64(x)))
+gamma(x::Float64) = _gamma(x)
+gamma(x::Float32) = Float32(_gamma(Float64(x)))
 
 function _gamma(x::Float64)
     T = Float64
@@ -50,10 +50,9 @@ function _gamma(x::Float64)
     return z * p / q
 end
 
-
 function gamma(n::Integer)
     n < 0 && throw(DomainError(n, "`n` must not be negative."))
-    n == 0 && return Inf*float(n)
+    n == 0 && return Inf*one(n)
     n > 20 && return gamma(float(n))
     @inbounds return Float64(factorial(n-1))
 end

test/gamma_test.jl

@@ -3,3 +3,6 @@ x = rand(10000)*170
 @test SpecialFunctions.gamma.(BigFloat.(-x)) ≈ Bessels.gamma.(-x)
 @test isnan(Bessels.gamma(NaN))
 @test isinf(Bessels.gamma(Inf))
+
+x = [0, 1, 2, 3, 8, 15, 20, 30]
+@test SpecialFunctions.gamma.(x) ≈ Bessels.gamma.(x)