Contents

- 1 How do I know if neural network is working?
- 2 How is back-propagation used to attempt to improve a neural network’s accuracy?
- 3 How do you calculate back-propagation error?
- 4 How is a back propagation algorithm implemented in a neural network?
- 5 What is the goal of backpropagation in a network?
- 6 What are the hidden neurons in backpropagation?
- 7 How do you know if a neural network is accurate?

## How do I know if neural network is working?

How to verify that an implementation of a neural network works…

- Plotting some metrics (F1-score, accuracy, some cost, etc.)
- Looking at the evolution of matrix weights across epoch.
- In case of multiple layers, removing some layers and see if it still learns something.

## How is back-propagation used to attempt to improve a neural network’s accuracy?

Back-propagation is just a way of propagating the total loss back into the neural network to know how much of the loss every node is responsible for, and subsequently updating the weights in such a way that minimizes the loss by giving the nodes with higher error rates lower weights and vice versa.

## How do you calculate back-propagation error?

The backprop algorithm then looks as follows:

- Initialize the input layer:
- Propagate activity forward: for l = 1, 2., L, where bl is the vector of bias weights.
- Calculate the error in the output layer:
- Backpropagate the error: for l = L-1, L-2., 1,
- Update the weights and biases:

## How is a back propagation algorithm implemented in a neural network?

All inputs from the input layer along with the bias are forwarded to each neuron in the hidden layer where each neuron performs a weighted summation of the input and sends the activation results as output to the next layer. The process repeats until the data final exits form the network through the output layer.

## What is the goal of backpropagation in a network?

The Backwards Pass. Our goal with backpropagation is to update each of the weights in the network so that they cause the actual output to be closer the target output, thereby minimizing the error for each output neuron and the network as a whole.

Additionally, the hidden and output neurons will include a bias. Here’s the basic structure: In order to have some numbers to work with, here are the initial weights, the biases, and training inputs/outputs:

## How do you know if a neural network is accurate?

Once the forward propagation is done and the neural network gives out a result, how do you know if the result predicted is accurate enough. This is where the back propagation algorithm is used to go back and update the weights, so that the actual values and predicted values are close enough.