From 5866fe52e6d2cf61b311936becb6def057ddf22a Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Fri, 28 Aug 2020 15:30:49 +0100
Subject: [PATCH] Fix integer evaluation (#29)

* Fix integer arguments

* Update Project.toml
---
 Project.toml            |  2 +-
 src/specialfunctions.jl | 18 +++++++++---------
 test/runtests.jl        |  4 ++++
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/Project.toml b/Project.toml
index 818efad..0751c2b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "HypergeometricFunctions"
 uuid = "34004b35-14d8-5ef3-9330-4cdb6864b03a"
-version = "0.3.2"
+version = "0.3.3"
 
 [deps]
 DualNumbers = "fa6b7ba4-c1ee-5f82-b5fc-ecf0adba8f74"
diff --git a/src/specialfunctions.jl b/src/specialfunctions.jl
index b94f083..8e2b24b 100644
--- a/src/specialfunctions.jl
+++ b/src/specialfunctions.jl
@@ -347,7 +347,7 @@ end
 
 
 function _₂F₁maclaurin(a::Number, b::Number, c::Number, z::Number)
-    T = promote_type(typeof(a), typeof(b), typeof(c), typeof(z))
+    T = float(promote_type(typeof(a), typeof(b), typeof(c), typeof(z)))
     S₀, S₁, j = one(T), one(T)+a*b*z/c, 1
     while errcheck(S₀, S₁, 10eps(real(T))) || j ≤ 1
         rⱼ = (a+j)/(j+1)*(b+j)/(c+j)
@@ -358,7 +358,7 @@ function _₂F₁maclaurin(a::Number, b::Number, c::Number, z::Number)
 end
 
 function _₂F₁maclaurinalt(a::Number, b::Number, c::Number, z::Number)
-    T = promote_type(typeof(a), typeof(b), typeof(c), typeof(z))
+    T = float(promote_type(typeof(a), typeof(b), typeof(c), typeof(z)))
     C, S, j = one(T), one(T), 0
     while abs(C) > 10abs(S)*eps(real(T)) || j ≤ 1
         C *= (a+j)/(j+1)*(b+j)/(c+j)*z
@@ -369,7 +369,7 @@ function _₂F₁maclaurinalt(a::Number, b::Number, c::Number, z::Number)
 end
 
 function _₂F₁continuation(s::Number, t::Number, c::Number, z₀::Number, z::Number)
-    T = promote_type(typeof(s), typeof(t), typeof(c), typeof(z₀), typeof(z))
+    T = float(promote_type(typeof(s), typeof(t), typeof(c), typeof(z₀), typeof(z)))
     izz₀, d0, d1 = inv(z-z₀), one(T), s/(2s-t+one(T))*((s+1)*(1-2z₀)+(t+1)*z₀-c)
     S₀, S₁, izz₀j, j = one(T), one(T)+d1*izz₀, izz₀, 2
     while errcheck(S₀, S₁, 10eps(real(T))) || j ≤ 2
@@ -381,7 +381,7 @@ function _₂F₁continuation(s::Number, t::Number, c::Number, z₀::Number, z::
 end
 
 function _₂F₁continuationalt(a::Number, c::Number, z₀::Number, z::Number)
-    T = promote_type(typeof(a), typeof(c), typeof(z₀), typeof(z))
+    T = float(promote_type(typeof(a), typeof(c), typeof(z₀), typeof(z)))
     izz₀ = inv(z-z₀)
     e0, e1 = one(T), (a+one(T))*(one(T)-2z₀)+(2a+one(T))*z₀-c
     f0, f1 = zero(T), one(T)-2z₀
@@ -402,7 +402,7 @@ function _₂F₁continuationalt(a::Number, c::Number, z₀::Number, z::Number)
 end
 
 function _₂F₁logsum(a::Number, b::Number, z::Number, w::Number, s::Int)
-    T = promote_type(typeof(a), typeof(b), typeof(z), typeof(w))
+    T = float(promote_type(typeof(a), typeof(b), typeof(z), typeof(w)))
     cⱼ = 2digamma(one(T))-digamma(a)-digamma(b)+s*log1p(-z)
     C, S, j = one(T), cⱼ, 0
     while abs(C) > 10abs(S)*eps(real(T)) || j ≤ 1
@@ -415,7 +415,7 @@ function _₂F₁logsum(a::Number, b::Number, z::Number, w::Number, s::Int)
 end
 
 function _₂F₁logsumalt(a::Number, b::Number, z::Number, w::Number)
-    T = promote_type(typeof(a), typeof(b), typeof(z), typeof(w))
+    T = float(promote_type(typeof(a), typeof(b), typeof(z), typeof(w)))
     d, cⱼ = one(T)-b, 2digamma(one(T))-digamma(a)-digamma(b)-log(-w)
     C, S, j = one(T), cⱼ, 0
     while abs(C) > 10abs(S)*eps(real(T)) || j ≤ 1
@@ -428,7 +428,7 @@ function _₂F₁logsumalt(a::Number, b::Number, z::Number, w::Number)
 end
 
 function _₂F₁taylor(a::Number, b::Number, c::Number, z::Number)
-    T = promote_type(typeof(a), typeof(b), typeof(c), typeof(z))
+    T = float(promote_type(typeof(a), typeof(b), typeof(c), typeof(z)))
     z₀ = abs(z) < 1 ? ρϵ*sign(z) : sign(z)/ρϵ
     q₀, q₁ = _₂F₁(a, b, c, z₀), a*b/c*_₂F₁(a+1, b+1, c+1, z₀)
     S₀, zz₀ = q₀, z-z₀
@@ -443,7 +443,7 @@ function _₂F₁taylor(a::Number, b::Number, c::Number, z::Number)
 end
 
 function _₃F₂maclaurin(a₁, a₂, a₃, b₁, b₂, z)
-    T = promote_type(typeof(a₁), typeof(a₂), typeof(a₃), typeof(b₁), typeof(b₂), typeof(z))
+    T = float(promote_type(typeof(a₁), typeof(a₂), typeof(a₃), typeof(b₁), typeof(b₂), typeof(z)))
     S₀, S₁, j = one(T), one(T)+(a₁*a₂*a₃*z)/(b₁*b₂), 1
     while errcheck(S₀, S₁, 10eps(real(T))) || j ≤ 1
         rⱼ = ((a₁+j)*(a₂+j)*(a₃+j))/((b₁+j)*(b₂+j)*(j+1))
@@ -454,7 +454,7 @@ function _₃F₂maclaurin(a₁, a₂, a₃, b₁, b₂, z)
 end
 
 function pFqmaclaurin(a::AbstractVector{S}, b::AbstractVector{U}, z::V) where {S, U, V}
-    T = promote_type(S, U, V)
+    T = float(promote_type(S, U, V))
     S₀, S₁, j = one(T), one(T)+prod(a)*z/prod(b), 1
     while errcheck(S₀, S₁, 10eps(real(T))) || j ≤ 1
         rⱼ = inv(j+one(T))
diff --git a/test/runtests.jl b/test/runtests.jl
index e49146b..782d793 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -424,4 +424,8 @@ end
             @test pFqweniger(S[α, β], S[γ], z) ≈ CS(pFq(T[α, β], T[γ], CT(z))) atol=atol rtol=rtol
         end
     end
+
+    @testset "Integer arguments" begin
+        @test _₂F₁(1, 0, 3, -1) ≡ _₂F₁(1.0, 0, 3, -1) ≡ 1.0
+    end
 end