fix a bug

src/autodiff/instructs.jl

@@ -30,18 +30,18 @@ end
 end
 
 @i @inline function ⊖(-)(out!::GVar, x::GVar, y::GVar)
-    value(out!) -= value(x) + value(y)
+    value(out!) -= value(x) - value(y)
     grad(x) += identity(grad(out!))
     grad(y) -= identity(grad(out!))
 end
 
 @i @inline function ⊖(-)(out!::GVar, x::Real, y::GVar)
-    value(out!) -= value(x) + value(y)
+    value(out!) -= value(x) - value(y)
     grad(y) -= identity(grad(out!))
 end
 
 @i @inline function ⊖(-)(out!::GVar, x::GVar, y::Real)
-    value(out!) -= value(x) + value(y)
+    value(out!) -= value(x) - value(y)
     grad(x) += identity(grad(out!))
 end
 
@@ -200,6 +200,8 @@ end
     grad(x) += grad(out!) * x2
     ~@routine
 end
+@nograd ⊖(abs2)(a!::GVar, b::Real)
+@nograd ⊖(abs2)(a!::Real, b::GVar)
 
 for op in [:*, :/, :^, :+, :-]
     @eval @nograd ⊖($op)(out!::GVar, x::Real, y::Real)

src/autodiff/vars.jl

@@ -34,9 +34,6 @@ Attach a gradient field to `x`.
     end
     @i function GVar(x::Function)
     end
-    @i function GVar(x::AbstractArray)
-        GVar.(x)
-    end
     @i function GVar(x::Tuple)
         GVar.(x)
     end
@@ -47,6 +44,9 @@ end
 GVar(x::Complex) = Complex(GVar(x.re), GVar(x.im))
 GVar(x::Complex, y::Complex) = Complex(GVar(x.re, y.re), GVar(x.im, y.im))
 (_::Inv{GVar})(x::Complex) = Complex((~GVar)(x.re), (~GVar)(x.im))
+GVar(x::AbstractArray) = GVar.(x)
+GVar(x::AbstractArray, y::AbstractArray) = GVar.(x, y)
+(_::Inv{GVar})(x::AbstractArray) = (~GVar).(x)
 
 Base.copy(b::GVar) = GVar(b.x, copy(b.g))
 Base.zero(x::GVar) = GVar(Base.zero(x.x), Base.zero(x.g))

test/autodiff/vars.jl

@@ -35,7 +35,7 @@ end
 @testset "assign tuple" begin
     x = 0.3
     z = Loss(0.3)
-    @instr GVar.((x,))
+    @instr for i=1:length(x) GVar(x) end
     @test x === GVar(0.3)
 end