What is K-means Clustering
Tags: datascience
Published: 2023-05-29 08:58:27

K-means clustering is an unsupervised machine learning algorithm used to group a set of data points into K distinct clusters. The algorithm aims to minimize the within-cluster sum of squared distances, which means that data points within the same cluster are similar to each other and dissimilar to those in other clusters.

The algorithm works by initially randomly selecting K points as centroids, which serve as the initial cluster centers. Each data point is then assigned to the nearest centroid based on a distance metric, typically Euclidean distance. After the initial assignment, the centroids are updated by computing the mean of the data points assigned to each cluster. This process iteratively repeats until convergence is reached, where the centroids no longer change significantly.

K-means clustering is an iterative optimization algorithm that partitions the data points into clusters by minimizing the within-cluster sum of squared distances. The resulting clusters are characterized by their centroids, which represent the center points of the clusters. The algorithm does not require prior knowledge or labeled data; instead, it identifies patterns and relationships solely based on the inherent similarities within the data. By obtaining a [Data science internship for freshers](https://www.edureka.co/internship/data-science-and-machine-learning-program), you can advance your career in Data science. With this course, you can demonstrate your expertise Intern certificate will only be given to learners who complete the project within the set timeline, help other learners and work with them as a team, and come up with innovative ideas during the development of the product, many more fundamental concepts, and many more critical concepts among others.

The choice of K, the number of clusters, is typically determined by the user based on domain knowledge or using techniques like the elbow method or silhouette score. K-means clustering is widely used in various fields, including customer segmentation, data mining, image processing, and pattern recognition. However, it is sensitive to the initial selection of centroids and can converge to suboptimal solutions, so it is often run multiple times with different initializations to improve the quality of clustering results.

**Here are key aspects of the K-means clustering algorithm:**

**Cluster Centroids:** The algorithm starts by randomly selecting K data points as initial cluster centroids. These centroids act as representative points for each cluster.

**Data Assignment:** Each data point in the dataset is then assigned to the cluster whose centroid is closest to it. The distance between a data point and a centroid is typically measured using Euclidean distance, although other distance metrics can also be used.

**Centroid Update:** After the initial assignment, the centroids of the clusters are updated by computing the mean of all the data points assigned to each cluster. The updated centroids represent the new center points for the clusters.

**Iterative Process:** The assignment and centroid update steps are repeated iteratively until convergence is achieved. Convergence occurs when the centroids no longer change significantly or when a maximum number of iterations is reached.

**Optimization Objective:** The goal of K-means clustering is to minimize the within-cluster sum of squared distances. This means that data points within a cluster are as similar as possible to each other, while data points from different clusters are as dissimilar as possible.

**Choosing K:** Selecting an appropriate value for K is important in K-means clustering. It can be determined based on domain knowledge, data exploration, or by using techniques like the elbow method, silhouette score, or gap statistic.

K-means clustering is widely used in various applications such as customer segmentation, image compression, anomaly detection, and pattern recognition. It is a simple and efficient algorithm but is sensitive to the initial random selection of centroids and can produce different results for different initializations. Therefore, it is common to run the algorithm multiple times with different initializations to improve the robustness of the results.