Fix log1p with complex Irrational argument (#21784)

JuliaLang · May 14, 2017 · 320892a · 320892a
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commit 320892a
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diff --git a/base/complex.jl b/base/complex.jl
@@ -546,7 +546,7 @@ function log1p(z::Complex{T}) where T
         # This is based on a well-known trick for log1p of real z,
         # allegedly due to Kahan, only modified to handle real(u) <= 0
         # differently to avoid inaccuracy near z==-2 and for correct branch cut
-        u = float(one(T)) + z
+        u = one(float(T)) + z
         u == 1 ? convert(typeof(u), z) : real(u) <= 0 ? log(u) : log(u)*z/(u-1)
     elseif isnan(zr)
         Complex(zr, zr)

diff --git a/test/complex.jl b/test/complex.jl
@@ -948,5 +948,6 @@ end
     for x in (pi, e, catalan) # No need to test all of them
         @test typeof(Complex(x, x)) == Complex{typeof(x)}
         @test exp(complex(x, x)) ≈ exp(x) * cis(x)
+        @test log1p(complex(x, x)) ≈ log(1 + complex(x, x))
     end
 end