Understanding Epoch in Machine Learning
Definition and Importance:
- What does an epoch signify in Machine Learning (ML)? A single pass through the entirety of the training data by the algorithm is termed as an epoch in ML. It's a vital hyperparameter that determines the number of times the complete training dataset goes through the machine learning algorithm. Each epoch updates the internal parameters of the dataset. Consequently, the gradient-based learning method is usually named after a single batch epoch.
Characteristics of Epoch:
- Generally, the batch size of an epoch is one, and it's always quantified as an integer. This can also be represented as an iteration of entire data set travelling through a for-loop, designated by epoch number. During training, epochs could number in the thousands and the procedure continues until the model error has satisfactorily decreased. Conventionally, examples and tutorials use numbers like 10, 100, 1000 and above.
- For training purposes, line graphs can be plotted with ML epochs defining the X-axis and the skill or model error on the Y-axis. These line plots, known as the learning curves, can be utilized to diagnose problems including underfitting, overfitting, or suitable learning of the training set.
Epoch vs. Batch:
- Regarding Epoch and Batch in Machine Learning, one needs to understand that after processing a certain number of samples, the model updates, called sample batch size. Similar importance is given to the total passes in the training dataset, known as the epoch. Batch size generally is 1 and can be equal to or less than the total number in the training dataset.
Training Number in Neural Network:
- The training number in a neural network, also termed as the epoch, usually lies within a range of 1 to infinity, indicating that the procedure can persist indefinitely. A constant epoch number and the rate factor being zero over time can be employed to halt the algorithm.
Hyper-parameters in Machine Learning:
- Both batch size and epoch emerge as hyper-parameters in machine learning of learning algorithms. They are adjudged as integer values by the training model and being non-internal model parameters, they aren't discovered by a learning process and have to be designated during algorithm's training.
- In relation to key takeaways, the term epoch in ML refers to the total times the algorithm has traversed through the whole training dataset. When dealing with large volume of data, it's standard to partition the dataset into batches. Some people loosely refer the process of running a single batch through the model as an iteration.
- In a neural network, epoch is equivalent to a total cycle in the dataset. A network generally demands more epochs for its training. It is understandable, therefore, that the more epochs used, the better the generalization for new inputs.
- Epoch is often misunderstood with iteration. The iterations needed to finish one epoch equates to the number of steps or batches through segmented packets of training data. The network, by seeing previous data and reassessing parameters, avoids bias based on the last few datapoints during the training.
Limitations and Cautions:
- Nonetheless, it should be noted that allowing a network to familiarize itself with the data for successive epochs doesn’t ensure convergence or improvement. Despite some efforts to turn this process into an algorithm, understanding the data itself is generally required. Therefore, deciding on the suitable number of epochs for a network is an art in machine learning.
- Real-world application data being complex and varied, achieving accurate test data results may necessitate hundreds to thousands of epochs. Additionally, the label 'epoch' can acquire different meanings based on the particular context.