Adamax is an extension of the Adam optimizer and is based on the infinity norm.

## Learning rate

The learning rate is controlling the size of the update steps along the gradient. This parameter sets how much of the gradient you update with, where 1 = 100% but normally you set much smaller learning rate, e.g., 0.001.

In our rolling ball analogy, we’re calculating where the ball should roll next in discrete steps (not continuous). How long these discrete steps are is the learning rate.

Choosing a good learning rate is important when training a neural network. The best learning rate is dependent on the individual problem & model. If the ball rolls carefully with a small learning rate we can expect to make consistent but very small progress (this corresponds to having a small learning rate). The risk though is that the ball gets stuck in a local minima not reaching the global minima.

Figure 1. Learning rate

Larger learning rate mean that the weights are changed more every iteration, so that they may reach their optimal value faster, but may also miss the exact optimum.

Smaller learning rate mean that the weights are changed less every iteration, so it may take longer time to reach their optimal value, but they are less likely to miss optima of the loss function.

Learning rate scheduling allows you to use large steps during the first few epochs, then progressively reduce the step size as the weights come closer to their optimal value.

## Learning rate decay

The value here defines the process of gradually decreasing the learning rate during training, in order to help speed up its steps along the gradient.

## B and B2 rate

This settings adjust the exponential decay avarage parameters, that are used by the optimizer to gain momentum.