What may happen if you set the momentum hyperparameter too close to 1 (e.g., 0.99999) when using an SGD optimizer?

When using an SGD optimizer, if you set the momentum hyperparameter too near to one (e.g., 0.99999), the algorithm may fluctuate around the optimal result. This is because the momentum term will lead the algorithm to continue moving in the same direction even though it is no longer moving towards its optimal result. This can cause the algorithm to take longer to converge and may also result in overfitting.

It is important to note that the momentum hyperparameter is chosen based on the individual issue, dataset, and network design. A momentum value in the range of 0.9 to 0.99 is most typically utilised. It is advised that you experiment with and tweak the momentum hyperparameter to obtain the best balance of convergence speed and stability for your unique activity.