Principal Component Analysis

Curse of dimensionality

Curse of dimensionality in machine learning refers to the challenges and computational complexities that arise when dealing with a large number of features (high-dimensional data/high-dimensional feature space). As the number of features or dimensions increases, the amount of data needed to maintain reliable and meaningful patterns also increases, often leading to increased data and computational demands and the risk of overfitting.

Example

Consider a product recommendation system where each product is described by multiple features such as price, size, color, brand, and so on. As the number of features increases, possible combinations grow exponentially, making it harder to find meaningful relationships between products and user preferences. This high-dimensional data can lead to sparse data points, which makes accurate predictions more challenging and requires more data to avoid unreliable results, hence, illustrating the curse of dimensionality.