Clustering algorithm [closed]

1. Is KNN a clustering algorithm?
2. Does K-means always converge?
3. Is PCA a clustering method?

Is KNN a clustering algorithm?

Difference between K-Nearest Neighbor(K-NN) and K-Means Clustering. K-NN is a Supervised machine learning while K-means is an unsupervised machine learning. K-NN is a classification or regression machine learning algorithm while K-means is a clustering machine learning algorithm.

Does K-means always converge?

While K-means shall always converge to at least a local minima (in sufficient number of iterations), its convergence to a global minima is not guaranteed. Consider the following example: In the below figure we have a set of blue points on the left side, and a set of red points on the right side.

Is PCA a clustering method?

Principal component analysis (PCA) is a technique used to reduce the dimensions of data consisting of several dependent variables while maintaining the variance in the data. PCA can be used to stabilize measurements in statistical analysis, one of which is cluster analysis.