Merge branch 'complex_utils' of https://github.com/simeonschaub/Chain…

…Rules.jl into complex_utils

src/rulesets/Base/base.jl

@@ -83,14 +83,19 @@
 
 @scalar_rule(hypot(x, y), (x / Ω, y / Ω))
 @scalar_rule(sincos(x), @setup((sinx, cosx) = Ω), cosx, -sinx)
-@scalar_rule(atan(x, y), @setup(u = x^2 + y^2), (y / u, -x / u))
-
+@scalar_rule(atan(y, x), @setup(u = x^2 + y^2), (x / u, -y / u))
 @scalar_rule(max(x, y), @setup(gt = x > y), (gt, !gt))
 @scalar_rule(min(x, y), @setup(gt = x > y), (!gt, gt))
 @scalar_rule(mod(x, y), @setup((u, nan) = promote(x / y, NaN16)),
              (ifelse(isint, nan, one(u)), ifelse(isint, nan, -floor(u))))
 @scalar_rule(rem(x, y), @setup((u, nan) = promote(x / y, NaN16)),
              (ifelse(isint, nan, one(u)), ifelse(isint, nan, -trunc(u))))
+@scalar_rule(angle(x::Complex), @setup(u = abs2(x)), Wirtinger(-im//2 * x' / u, im//2 * x / u))
+@scalar_rule(angle(x::Real), Zero())
+@scalar_rule(real(x::Complex), Wirtinger(1//2, 1//2))
+@scalar_rule(real(x::Real), One())
+@scalar_rule(imag(x::Complex), Wirtinger(-im//2, im//2))
+@scalar_rule(imag(x::Real), Zero())
 
 # product rule requires special care for arguments where `mul` is non-commutative
 

test/rulesets/Base/base.jl

@@ -99,6 +99,18 @@
         end
     end
 
+    @testset "Unary complex functions" begin
+        for x in rand.((Int, Float32, Float64, complex.((Float32, Float64))...))
+            test_scalar(real, x)
+            test_scalar(imag, x)
+            test_scalar(abs, x)
+            test_scalar(abs, x)
+            test_scalar(angle, x)
+            test_scalar(abs2, x)
+            test_scalar(conj, x)
+        end
+    end
+
     @testset "*(x, y)" begin
         x, y = rand(3, 2), rand(2, 5)
         z, (dx, dy) = rrule(*, x, y)

test/runtests.jl

@@ -13,7 +13,7 @@ using Test
 using ChainRulesCore: add, cast, extern, accumulate, accumulate!, store!, @scalar_rule,
     Wirtinger, wirtinger_primal, wirtinger_conjugate, add_wirtinger, mul_wirtinger,
     Zero, add_zero, mul_zero, One, add_one, mul_one, Casted, cast, add_casted, mul_casted,
-    DNE, Thunk, Casted, DNERule
+    DNE, Thunk, Casted, DNERule, AbstractDifferential
 
 include("test_util.jl")