From e95b5d21425d6c757088d284f5a62adda4c7baa4 Mon Sep 17 00:00:00 2001
From: "David P. Sanders" <dpsanders@gmail.com>
Date: Fri, 9 Aug 2019 12:55:04 -0400
Subject: [PATCH] Fix power_rev for exponents that are integer-valued but not
 integer-typed (#38)

* Treat exponent 2.0 as if it were 2 by calling the integer version of power_rev

* Fix return type and add test

* Bump version
---
 Project.toml      | 2 +-
 src/arithmetic.jl | 5 +++++
 test/runtests.jl  | 4 ++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 3ba2059..2b143d9 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "IntervalContractors"
 uuid = "15111844-de3b-5229-b4ba-526f2f385dc9"
-version = "0.4.0"
+version = "0.4.1"
 
 [deps]
 IntervalArithmetic = "d1acc4aa-44c8-5952-acd4-ba5d80a2a253"
diff --git a/src/arithmetic.jl b/src/arithmetic.jl
index bd7c00d..ee645a6 100644
--- a/src/arithmetic.jl
+++ b/src/arithmetic.jl
@@ -120,6 +120,11 @@ end
 
 function power_rev(a::Interval, b::Interval, c::Interval)  # a = b^c
 
+    if isinteger(c)
+        temp = power_rev(a, b, Int(inf(c)))  # use version with integer
+        return (temp[1], temp[2], interval(temp[3]))
+    end
+
     b_new = b ∩ ( a^(inv(c) ))
     c_new = c ∩ (log(a) / log(b))
 
diff --git a/test/runtests.jl b/test/runtests.jl
index fa8b510..be1dfad 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -20,4 +20,8 @@ using Test
 
         @test mul_rev(z, x, y) == (2..10, 2..5, 0.4..1.0)
     end
+
+    @testset "Exponents with integer values but not types" begin
+        @test power_rev(-Inf..Inf, -4..4, 2.0) ==  (-∞..∞, -4..4, 2.0)
+    end
 end