Hidden Layer

A layer that is not the output and not the input layer.

Estimate its size

With the Pearson Correlation we can see when two Neurons are doing the same job.

$⟨f_i,f_j⟩=\frac{{\sum }_t\left(f_i(t)-{\bar{f}}_i\right)\left(f_j(t)-{\bar{f}}_j\right)}{\sqrt{{\sum }_t{\left(f_i(t)-{\bar{f}}_i\right)}^2{\sum }_t{\left(f_j(t)-{\bar{f}}_j\right)}^2}}$ When the highest Correlation is near one we have to reduce the size. Otherwise we can increase it.