Supplementary for learning hierararchical clustering

For statistical learning purpose: some toy datasets (double moons, six artificial datasets, etc.), dendrogram, visualizalization

This supplementary materials includes several 2D toy datasets for beginners to learn the effect of different linkage on hierarchical clustering, and go one more step on how to visualize the clustering result with the same color in dendrogram.

See demo.m for an introduction. Toy datasets include double moons, 2 or 3 spirals, etc.

It includes almost everything from the sources but is different from the sources since some functions have been updated and no longer used as years go by.
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Sources:

Toy datasets come from:
https://www.mathworks.com/matlabcentral/fileexchange/41459-6-functions-for-generating-artificial-datasets
https://stackoverflow.com/questions/49461217/separate-double-moon-classification-with-a-line-in-matlab
https://faculty.ucmerced.edu/mcarreira-perpinan/teaching/CSE176/Labs/datasets/

Ideas come from:
https://chalmers.instructure.com/courses/9441/assignments/16140
https://www.mathworks.com/matlabcentral/answers/96273-how-can-i-color-my-dendrogram-plot-such-that-the-colors-correspond-to-clusters-generated-by-the-clus
https://stackoverflow.com/questions/34948500/how-to-change-the-cluster-colours-in-a-dendrogram