fix some issues

#75
#86

Author: MikaelSlevinsky

Project.toml

@@ -1,6 +1,6 @@
 name = "HypergeometricFunctions"
 uuid = "34004b35-14d8-5ef3-9330-4cdb6864b03a"
-version = "0.3.27"
+version = "0.3.28"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/gauss.jl

@@ -8,9 +8,11 @@ function _₂F₁(a, b, c, z; method::Symbol = :general, kwds...)
     if real(b) < real(a)
         return _₂F₁(b, a, c, z; method = method, kwds...) # ensure a ≤ b
     elseif isequal(a, c) # 1. 15.4.6
-        return exp(-b*log1p(-z))
+        return pFq((b, ), (), z)
     elseif isequal(b, c) # 1. 15.4.6
-        return exp(-a*log1p(-z))
+        return pFq((a, ), (), z)
+    elseif isequal(a, 0) || isequal(b, 0)
+        return one(z)
     elseif isequal(c, 0.5)
         if isequal(a+b, 0) # 31. 15.4.11 & 15.4.12
             return cosnasinsqrt(2b, z)

src/generalized.jl

@@ -54,6 +54,7 @@ pFq
 
 pFq(::Tuple{}, ::Tuple{}, z; kwds...) = exp(z)
 pFq(α::NTuple{1}, ::Tuple{}, z; kwds...) = exp(-α[1]*log1p(-z))
+pFq(α::NTuple{1, <: Integer}, ::Tuple{}, z; kwds...) = (1-z)^-α[1]
 pFq(α::NTuple{1}, β::NTuple{1}, z; kwds...) = _₁F₁(α[1], β[1], z; kwds...)
 pFq(α::NTuple{2, Any}, β::NTuple{1}, z; kwds...) = _₂F₁(α[1], α[2], β[1], z; kwds...)
 

test/runtests.jl

@@ -527,6 +527,15 @@ end
     @testset "Integer arguments" begin
         @test _₂F₁(1, 0, 3, -1) ≡ _₂F₁(1.0, 0, 3, -1) ≡ 1.0
     end
+
+    @test "a or b == c" begin
+        pFq((-1, 0), (-1, ), 2) == 1.0 # From #86
+    end
+
+    @testset "a or b == 0" begin
+        @test pFq((0, 0), (1/2, ), 5/4) == 1.0 # From #75
+        @test pFq((0.5, 0.0), (1.5, ), 1) == 1.0 # From #75
+    end
 end
 
 @testset "₅F₄" begin # Tests the generic algorithms for pFqdrummond and pFqweniger