fixes #114

src/tracker/lib.jl

@@ -58,6 +58,15 @@ Base.findfirst(xs::TrackedArray, args...) = findfirst(xs.data, args...)
 Base.mean(xs::TrackedArray) = TrackedArray(Call(mean, xs), toarray(xs.data, mean(xs.data)))
 Base.mean(xs::TrackedArray, region) = TrackedArray(Call(mean, xs, region))
 
+LinAlg.dot(xs::TrackedVector, ys::TrackedVector) = TrackedArray(Call(dot, xs, ys), toarray(xs.data, dot(data(xs), data(ys))))
+LinAlg.dot(xs::AbstractVector, ys::TrackedVector) = TrackedArray(Call(dot, xs, ys), toarray(xs.data, dot(data(xs), data(ys))))
+LinAlg.dot(xs::TrackedVector, ys::AbstractVector) = TrackedArray(Call(dot, xs, ys), toarray(xs.data, dot(data(xs), data(ys))))
+
+function back(::typeof(dot), Δ, xs, ys)
+  @back(xs, Δ.*ys)
+  @back(ys, Δ.*xs)
+end
+
 # Hacks to get std working
 Base.std(x::TrackedArray; mean = Base.mean(x)) =
   sqrt.(sum((x .- mean).^2) ./ (length(x)-1))

test/tracker.jl

@@ -38,6 +38,8 @@ end
 @test gradtest(x -> std(x), rand(5,5))
 @test gradtest(x -> std(x, 1), rand(5,5))
 
+@test gradtest((x, y) -> x .* y, rand(5), rand(5))
+
 @test gradtest(rand(5)) do x
   y = x.^2
   2y + x