Layer (Hidden Layer)

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Layer refers to a collection of nodes or neurons that process a set of input data or the output of previous layers. Among these layers, the hidden layer is a primary component that plays a significant role in the learning and predictive capabilities of the network. Positioned between the input and output layers, hidden layers are called as such because their individual states are not visible as a network input or output and they don’t interact with the outside world.


Each neuron in a hidden layer receives input from the nodes in the previous layer. It applies a weight to those inputs, sums them, adds a bias, and then passes the result through an activation function to produce an output. This output can then be forwarded to neurons in the next layer. The greater the number of hidden layers, the more complex are the features that the neural network can learn and abstract from the input data, thus making the model capable of solving more intricate problems.

Deploying an unnecessary amount of hidden layers or neurons might lead to overfitting, where the model learns the training data too well and performs poorly when exposed to unseen data. Choosing the optimal number of hidden layers and neurons is crucial for a balanced and well-performing model. This determination of the number of hidden layers and their respective size constitutes a major part of tuning a neural network model. These layers are fundamental blocks in crafting the network architecture, especially in deep learning models, which are often characterized by multiple hidden layers.

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