Hands-On Deep Learning with R

Investigating the hyperbolic tangent function

The hyperbolic tangent function, which is also known as tanh, is very similar to the sigmoid function; however, the lower bound of the curve is in negative space to better handle data containing negative values.

Aside from this one difference, everything else about the hyperbolic tangent function is the same as the sigmoid function, and like the sigmoid function, the hyperbolic tangent contains a derivative element and can be used with backpropagation.

Since tanh is bounded between -1 and 1, the gradient is larger and the derivative is more pronounced. Being bounded means that tanh is centered around 0, which can be advantageous in a model with a large number of hidden layers as the results from ...