How does Epoch affect Accuracy in Deep Learning Model?

Deep learning models have revolutionised the field of machine learning by delivering cutting-edge performance on a variety of tasks like speech recognition, image recognition, and natural language processing. These models’ accuracy is influenced by a number of factors, including model architecture, the quantity and quality of the training datasets, and the hyperparameters they employ. The number of training epochs, which controls how many times the model is trained on the full dataset, is one such hyperparameter. We shall discuss how epoch impacts a deep learning model’s accuracy in this article.

What is epoch?

A single pass over the complete training dataset constitutes an epoch in deep learning. The model uses backpropagation to update its parameters throughout each epoch in order to lower the loss function. The training phase goal is to minimise the loss function value, which quantifies how well the model performs on the training data.

An epoch is a whole cycle of training the machine learning model using the entire training dataset. Every training sample in the dataset is processed by the model during an epoch, and the weights and biases are changed to reflect the calculated loss or error.

The training dataset in deep learning is typically divided into smaller groups called batches, and the model analyses each batch sequentially, one at a time, throughout each epoch. The batch size, a hyperparameter that can be changed to improve the performance of the model, determines the number of batches in an epoch. On the validation dataset, the model performance may be assessed after each epoch. This helps to monitor the progress of the model.

Total number of training samples = 50000
Batch size = 250
Total number of iterations=Total number of training samples/Batch size=50000/250=200
Total number of iterations = 200
One epoch = 200 iterations

Effect of the epoch:

In a deep learning model, the link between the number of epochs and accuracy is not always straightforward, and it might change based on the particular dataset and model architecture being utilised. In General speaking, accuracy tends to increase with the number of epochs, as the model continues to refine its understanding of the training data. However, after a certain point, increasing the number of epochs can lead to overfitting, where the model becomes too focused on the training data and performs poorly on new, unseen data. This can cause the accuracy to plateau or even decrease.

Finding the ideal number of epochs that strikes a balance between underfitting and overfitting can be achieved by employing strategies like early stopping and learning rate schedules.

• Early stopping is a common technique that monitors the validation loss during training and stops the training when the validation loss starts to increase. This helps to prevent overfitting and improves the generalization performance of the model. This enhances the model’s generalisation capabilities and prevents overfitting.
• Learning rate schedules allow the model to converge to the optimal solution and avoid getting stuck in local minima by gradually lowering the learning rate throughout training. It reduces the learning rate throughout training to help the model to achieve the best results. This approach can enhance the generalisation capabilities of the model and help in avoiding local minima.

The number of epochs used during training is a critical hyperparameter that affects the performance of the model. If the number of epochs is set too low, the model may not have enough training time to learn the complicated patterns in the data, which results in underfitting. Underfitting happens when the model fails to capture the underlying patterns in the data, resulting in poor performance on both training and testing data.

On the other hand, if there are too many epochs, the model may memorise the training set, leading to overfitting. Overfitting occurs when a model performs badly on test data because it is very sophisticated and begins to fit noise in the data. This is owing to the model’s failure to generalise to new data because of its extensive learning of the training data.

Therefore, choosing the optimal number of epochs for a specific dataset and model architecture is necessary to achieve good performance. Using a validation dataset is one method for figuring out this value. Every epoch during training, the model is assessed on the validation dataset, and training is stopped when the validation loss starts to rise. This early-stopping technique aids in avoiding overfitting. 

Another approach to determining the optimal number of epochs is to use a learning rate schedule. To help the model achieve the optimum results, a learning rate schedule gradually lowers the learning rate throughout training. This method can improve the model’s generalisation abilities and help prevent local minima.

In deep learning, the layers of a neural network are typically trained in an end-to-end fashion, where the network learns to extract progressively more abstract and complex features as the information flows through the layers. It is common for the initial layers to learn simple and low-level features, such as edges or textures, while deeper layers learn more high-level features, such as object shapes or semantic representations.

The number of epochs required for training each layer depends on various factors, including the complexity of the task, the size of the dataset, the network architecture, and the initialization of the weights. In some cases, the deeper layers may require more epochs to converge and learn complex features, while the shallower layers may converge faster with fewer epochs.

Conclusion:

To summarise, the effect of the number of epochs on accuracy in a deep learning model is not a straightforward relationship and is affected by a variety of factors such as the dataset, model architecture, and training hyperparameters. In general, accuracy increases with the number of epochs, but overfitting might lead it to decrease after a given number of epochs. Using tactics like early stopping and learning rate schedule, which demand rigorous experimentation and evaluation of multiple factors, helps you achieve strong generalisation performance.