Cluster analysis, also called segmentation analysis or taxonomy analysis, partitions sample data into groups or clusters. Clusters are formed such that objects in the same cluster are very similar, and objects in different clusters are very distinct. Statistics and Machine Learning Toolbox provides several clustering techniques and measures of similarity (also called distance measures) to create the clusters. Additionally, cluster evaluation determines the optimal number of clusters for the data using different evaluation criteria. Cluster visualization options include dendrograms and silhouette plots. "Hierarchical Clustering" groups data over a variety of scales by creating a cluster tree or dendrogram. The tree is not a single set of clusters, but rather a multilevel hierarchy, where clusters at one level are joined as clusters at the next level. This allows you to decide the level or scale of clustering that is most appropriate for your application. The Statistics and Machine Learning Toolbox function clusterdata performs all of the necessary steps for you. It incorporates the pdist, linkage, and cluster functions, which may be used separately for more detailed analysis. The dendrogram function plots the cluster tree. "k-Means Clustering" is a partitioning method. The function kmeans partitions data into k mutually exclusive clusters, and returns the index of the cluster to which it has assigned each observation. Unlike hierarchical clustering, k-means clustering operates on actual observations (rather than the larger set of dissimilarity measures), and creates a single level of clusters. The distinctions mean that k-means clustering is often more suitable than hierarchical clustering for large amounts of data. "Clustering Using Gaussian Mixture Models" form clusters by representing the probability density function of observed variables as a mixture of multivariate normal densities. Mixture models of the gmdistribution class use an expectation maximization (EM) algorithm to fit data, which assigns posterior probabilities to each component density with respect to each observation. Clusters are assigned by selecting the component that maximizes the posterior probability. Clustering using Gaussian mixture models is sometimes considered a soft clustering method. The posterior probabilities for each point indicate that each data point has some probability of belonging to each cluster. Like k-means clustering, Gaussian mixture modeling uses an iterative algorithm that converges to a local optimum. Gaussian mixture modeling may be more appropriate than k-means clustering when clusters have different sizes and correlation within them. Neural Network Toolbox provides algorithms, pretrained models, and apps to create, train, visualize, and simulate both shallow and deep neural networks. You can perform classification, regression, clustering, dimensionality reduction, time-series forecasting, and dynamic system modeling and control. This book develops Cluster Techniques: Hierarchical Clustering, k-Means Clustering, Clustering Using Gaussian Mixture Models and Clustering using Neural Networks. The most important content in this book is the following: - Hierarchical Clustering - Algorithm Description - Similarity Measures - Linkages - Dendrograms - Verify the Cluster Tree - Create Clusters - k-Means Clustering - Create Clusters and Determine Separation - Determine the Correct Number of Clusters - Avoid Local Minima - Clustering Using Gaussian Mixture Models - Cluster Data from Mixture of Gaussian Distributions - Cluster Gaussian Mixture Data Using Soft Clustering - Tune Gaussian Mixture Models - Shallow Networks for Pattern Recognition, Clustering and Time Series - Fit Data with a Shallow Neural Network - Classify Patterns with a Shallow Neural Network - Cluster Data with a Self-Organizing Map - Shallow Neural Network Time-Series Prediction and Modeling