Epoch

November 21, 2023 - Around 2 mins mins to read

Understanding the Concept of Epoch

In the realm of artificial neural networks, an epoch is defined as a single iteration of the entire training dataset. The process of training a neural network typically involves multiple epochs. In simple terms, when we expose a neural network to training data in various patterns over multiple epochs, we expect to see improved generalization when it encounters new, unseen input (test data).

During each epoch, the underlying parameters of the model are adjusted. This is why the batch gradient descent learning algorithm is named after each batch within an epoch. The batch size, which is usually an integer value greater than or equal to 1, represents the number of samples processed in each epoch. Alternatively, it can be visualized as a for-loop that iterates through the entire training dataset.

The number of epochs required to train a model depends on various factors related to the data and the model’s objective. Converting this process into an algorithm typically requires a comprehensive understanding of the data.

An epoch is also used to describe the transmission of a complete dataset forward and backward through a neural network. To handle the large size of an epoch, it is divided into smaller batches that can be processed by the computer.

In the context of a blockchain network, an epoch represents a specific period of time. This time period is utilized to schedule events within the blockchain network, such as the distribution of incentives or the assignment of validators to validate transactions. The duration of an epoch varies depending on the blockchain protocol and is typically defined as the time required to complete a certain number of blocks on the chain.

For instance, in the Ethereum (ETH) protocol, an epoch corresponds to the completion of 30,000 blocks on the chain. The length of an epoch is determined by the speed at which transactions are processed and agreements are reached, but it generally remains around 100 hours.

Another example is the Cardano blockchain system, where an epoch is referred to as a unit of time. Cardano (ADA) utilizes Ouroboros Praos, a customized Proof-of-Stake (PoS) consensus mechanism that divides the blockchain into five-day epochs. Each epoch is further divided into slots, with each slot representing a 20-second interval. Currently, each epoch consists of 432,000 slots (equivalent to five days).