## What is hierarchical agglomerative clustering algorithm?

Hierarchical clustering algorithms group similar objects into groups called clusters. There are two types of hierarchical clustering algorithms: Agglomerative — Bottom up approach. Start with many small clusters and merge them together to create bigger clusters.

### Is hierarchical clustering the same as Agglomerative?

The agglomerative clustering is the most common type of hierarchical clustering used to group objects in clusters based on their similarity. It’s also known as AGNES (Agglomerative Nesting). The algorithm starts by treating each object as a singleton cluster.

**What are the optimization based on swarm intelligence?**

Swarm Intelligence Algorithms These algorithms include Genetic Algorithms (GA), Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO), Differential Evolution (DE), Artificial Bee Colony (ABC), Glowworm Swarm Optimization (GSO), and Cuckoo Search Algorithm (CSA).

**How does agglomerative clustering differ from divisive clustering?**

Divisive clustering is more efficient if we do not generate a complete hierarchy down to individual data points. Agglomerative clustering decides by considering the local patterns without considering global patterns initially, which cannot be reversed.

## What are the advantages of agglomerative hierarchical clustering?

Agglomerative Hierarchical Clustering (AHC) is a clustering (or classification) method which has the following advantages: It works from the dissimilarities between the objects to be grouped together. A type of dissimilarity can be suited to the subject studied and the nature of the data.

### What is the difference between agglomerative clustering and divisive clustering?

Agglomerative: This is a “bottom-up” approach: each observation starts in its own cluster, and pairs of clusters are merged as one moves up the hierarchy. Divisive: This is a “top-down” approach: all observations start in one cluster, and splits are performed recursively as one moves down the hierarchy.

**What are the disadvantages of particle swarm optimization?**

The disadvantages of particle swarm optimization (PSO) algorithm are that it is easy to fall into local optimum in high-dimensional space and has a low convergence rate in the iterative process. The computational complexity of DWCNPSO is accepted when it is applied to solve the high-dimensional and complex problems.

**Is PSO a machine learning algorithm?**

Comparing with five years ago, for training the machine learning algorithms, there are fewer citations from studies that use heuristic methods such as Particle Swarm Optimization (PSO) or Genetic Algorithm (GA) methods.

## Is PSO artificial intelligence?

Particle swarm optimization (PSO) is an artificial intelligence (AI) technique that can be used to find approximate solutions to extremely difficult or impossible numeric maximization and minimization problems. The version of PSO I describe in this article was first presented in a 1995 research paper by J.

### Which are the main differences between agglomerative hierarchical clustering and divisive hierarchical clustering?

**What is the overall complexity of the agglomerative hierarchical clustering?**

The time complexity of a naive ‘agglomerative cluster’ is O(n3) because in each of the N-1 iterations we scan the ‘N x N matrix’ dist mat exhaustively for the lowest distance. Using priority queue data structure we can reduce this complexity to . By using ‘some more optimizations’ it can be ‘brought down to ‘.