Unsupervised Learning

In unsupervised learning, the training data is unlabelled.

Typical unsupervised learning tasks include

  • clustering,
  • visualization,
  • dimensionality reduction / feature extraction,
  • anomaly detection and
  • association rule learning.

Some of the most important unsupervised learning algorithms include

  • clustering
    • k-means
    • hierarchical cluster analysis (HCA)
    • expectation maximization
  • visualization and dimensionality reduction
    • principle component analysis (PCA)
    • kernel PCA
    • locally-linear embedding (LLE)
    • t-distributed stochastic neighbor embedding (t-SNE)
  • association rule learning
    • Apriori
    • Eclat

References