Other unsupervised methods
We covered some of the basic unsupervised clustering methods here, but there are many more. The sklearn
documentation talks about many of the other distance-based clustering methods here: https://scikit-learn.org/stable/modules/clustering.html. Some other algorithms fall under the unsupervised machine learning model category, and many of these are matrix decomposition methods. The other unsupervised methods generally fall into dimensionality reduction techniques and topic modeling.
We saw one of these in Chapter 10, Preparing Data for Machine Learning: Feature Selection, Feature Engineering, and Dimensionality Reduction, on feature engineering – PCA, or principal component analysis. PCA can also be used as a preprocessing step for clustering or other unsupervised methods and sometimes improves clustering performance. SVD (singular value decomposition) is another dimensionality reduction technique. We can also use t-SNE, which is a more complex...