backprop for sigma

2016-08-24 15:41:30 +01:00 · 2016-08-24 15:41:30 +01:00 · 9675dc765d
parent e17d1cbe7a
commit 9675dc765d
2 changed files with 3 additions and 1 deletions
--- a/src/activation.jl
+++ b/src/activation.jl
@ -1,3 +1,5 @@
 export σ

 σ(x) = 1 ./ (1 .+ exp.(-x))
+
+back!(::typeof(σ), Δ, x) = Δ .* σ(x)./(1.-σ(x))
--- a/src/model.jl
+++ b/src/model.jl
@ -5,7 +5,7 @@ export Model, back!, update!, param
 abstract Model

 back!(m::Model, ∇) = error("Backprop not implemented for $(typeof(m))")
-update!(m::Model, η) = m
+update!(m, η) = m

 # Model parameters