Eager Learning
Eager learning is a paradigm in machine learning where the system constructs a comprehensive model that generalizes the relationships within the training data before it is asked to make predictions on new, unseen data. This approach contrasts with lazy learning, where the system defers the generalization process until a specific query is made. Eager learning algorithms invest computational resources upfront during the training phase to build a model that captures the underlying patterns and trends in the data.
This model is then used to make predictions or decisions without needing to revisit the training data for each new query. The advantage of eager learning is that once the model is built, making predictions on new data is typically fast. However, the initial model building can be computationally intensive and less flexible when dealing with changes or updates to the underlying data distribution.
Decision trees, neural networks, and support vector machines (SVMs) are classic examples of eager learning algorithms. For instance, a decision tree algorithm will analyze the training data during the training phase to build a tree structure where each node represents a decision point based on the input features, and each branch represents the outcome of that decision leading to a final prediction at the leaves. Once the tree is built, it can quickly classify new instances by following the decisions encoded in the tree structure.
Similarly, a neural network learns by adjusting the weights on its connections based on the training data to minimize prediction error, resulting in a model that can efficiently handle new inputs. In a practical scenario, an eager learning system might be employed in a spam detection application where the algorithm is trained on a labeled dataset of emails to learn the characteristics of spam and non-spam messages. Once trained, the model can instantly classify incoming emails without revisiting the entire dataset, enabling real-time filtering of spam messages.