Hierarchical clustering: Difference between revisions

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Hierarchical clustering, also known as hierarchical cluster analysis, is an algorithm that groups similar objects into groups called clusters.<ref>[https://www.displayr.com/what-is-hierarchical-clustering/ What is Hierarchical Clustering?]displayr.com</ref>  
'''Hierarchical clustering''', also known as hierarchical cluster analysis, is an algorithm that groups similar objects into groups called clusters.<ref>[https://www.displayr.com/what-is-hierarchical-clustering/ What is Hierarchical Clustering?]displayr.com</ref>  
   
   
== Strategies ==
== Strategies ==
Strategies for hierarchical clustering generally fall into two types<ref name="intro">[https://www.coursera.org/learn/machine-learning-with-python/lecture/cHku3/intro-to-hierarchical-clustering Intro to Hierarchical Clustering]Coursera</ref>:
Strategies for hierarchical clustering generally fall into two types<ref name="intro">[https://www.coursera.org/learn/machine-learning-with-python/lecture/cHku3/intro-to-hierarchical-clustering Intro to Hierarchical Clustering]Coursera</ref>:
* Divisive:
* Divisive: This type works on the assumption that all the feature vectors form a single set and then hierarchically go on dividing this group into different sets.<ref name="ssa">[https://www.sciencedirect.com/topics/computer-science/divisive-clustering Divisive Clustering]sciencedirect.com</ref>
* Agglomerative:
* Agglomerative: In this type partitions are visualized using a tree structure called [[dendrogram]].<ref name="ssa"/>


== Advantages vs disadvantages<ref>[https://www.coursera.org/learn/machine-learning-with-python/lecture/h2iAD/more-on-hierarchical-clustering Hierarchical Clustering]Coursera</ref> ==
== Advantages vs disadvantages<ref>[https://www.coursera.org/learn/machine-learning-with-python/lecture/h2iAD/more-on-hierarchical-clustering Hierarchical Clustering]Coursera</ref> ==

Revision as of 14:28, 14 April 2020

Hierarchical clustering, also known as hierarchical cluster analysis, is an algorithm that groups similar objects into groups called clusters.[1]

Strategies

Strategies for hierarchical clustering generally fall into two types[2]:

  • Divisive: This type works on the assumption that all the feature vectors form a single set and then hierarchically go on dividing this group into different sets.[3]
  • Agglomerative: In this type partitions are visualized using a tree structure called dendrogram.[3]

Advantages vs disadvantages[4]

Advantages

  • Hierarchical clustering does not require the number of clusters to be specified.
  • It is easy to implement.
  • Hierarchical clustering produces a dendogram, which hlps with understanding the data.

Disadvantages

  • The hierarchical algorithm can never do any previous steps throughout the algorithm
  • The time complexity for the clustering can result in very long computation times in comparison with efficient algorithms such as K-means.
  • If we have a large data set, it can become difficult to determine the correct number of clusters by the dendrogram.

References