diff --git a/src/activations/tanhActivation.jl b/src/activations/tanhActivation.jl
index d68b351..b8fe0bf 100644
--- a/src/activations/tanhActivation.jl
+++ b/src/activations/tanhActivation.jl
@@ -20,11 +20,9 @@ export tanhActivation
 function tanhActivation(Y::Array{T,2},doDerivative::Bool=false) where {T <: Number}
 
     A = tanh.(Y)
-    dA = similar(Y)
+    dA = zeros(A)
     if doDerivative
          dA .= one(T) .- A.^2
-    else
-        fill!(dA, zero(T))
     end
     return A, dA
 end