Setting up the back propagation algorithm, part 1

The four equations provide us with a way of computing the gradients of the cost function. Let us write this out in the form of an algorithm.

First, we set up the input data $\boldsymbol{x}$ and the activations $\boldsymbol{z}_1$ of the input layer and compute the activation function and the pertinent outputs $\boldsymbol{a}^1$.

Secondly, we perform then the feed forward till we reach the output layer and compute all $\boldsymbol{z}_l$ of the input layer and compute the activation function and the pertinent outputs $\boldsymbol{a}^l$ for $l=1,2,3,\dots,L$.

Notation: The first hidden layer has $l=1$ as label and the final output layer has $l=L$.

• «
• 1
• ...
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• 51
• 52
• ...
• 100
• »