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Posted to issues@spark.apache.org by "Fan Jiang (JIRA)" <ji...@apache.org> on 2015/01/28 22:41:34 UTC

[jira] [Updated] (SPARK-4259) Add Power Iteration Clustering Algorithm with Gaussian Similarity Function

     [ https://issues.apache.org/jira/browse/SPARK-4259?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Fan Jiang updated SPARK-4259:
-----------------------------
    Description: 
In recent years, spectral clustering has become one of the most popular modern clustering algorithms. It is simple to implement, can be solved efficiently by standard linear algebra software, and very often outperforms traditional clustering algorithms such as the k-means algorithm.

Power iteration clustering is a scalable and efficient algorithm for clustering points given pointwise mutual affinity values.  Internally the algorithm:

computes the Gaussian distance between all pairs of points and represents these distances in an Affinity Matrix
calculates a Normalized Affinity Matrix
calculates the principal eigenvalue and eigenvector
Clusters each of the input points according to their principal eigenvector component value

Details of this algorithm are found within [Power Iteration Clustering, Lin and Cohen]{www.icml2010.org/papers/387.pdf}


  was:
In recent years, spectral clustering has become one of the most popular modern clustering algorithms. It is simple to implement, can be solved efficiently by standard linear algebra software, and very often outperforms traditional clustering algorithms such as the k-means algorithm.

We implemented the unnormalized graph Laplacian matrix by Gaussian similarity function. A brief design looks like below:

Unnormalized spectral clustering

Input: raw data points, number k of clusters to construct: 

• Comupte Similarity matrix S ∈ Rn×n, .
• Construct a similarity graph. Let W be its weighted adjacency matrix.
• Compute the unnormalized Laplacian L = D - W. where D is the Degree diagonal matrix
• Compute the first k eigenvectors u1, . . . , uk of L.
• Let U ∈ Rn×k be the matrix containing the vectors u1, . . . , uk as columns.
• For i = 1, . . . , n, let yi ∈ Rk be the vector corresponding to the i-th row of U.
• Cluster the points (yi)i=1,...,n in Rk with the k-means algorithm into clusters C1, . . . , Ck.

Output: Clusters A1, . . . , Ak with Ai = { j | yj ∈ Ci }.



        Summary: Add Power Iteration Clustering Algorithm with Gaussian Similarity Function  (was: Add Spectral Clustering Algorithm with Gaussian Similarity Function)

> Add Power Iteration Clustering Algorithm with Gaussian Similarity Function
> --------------------------------------------------------------------------
>
>                 Key: SPARK-4259
>                 URL: https://issues.apache.org/jira/browse/SPARK-4259
>             Project: Spark
>          Issue Type: New Feature
>          Components: MLlib
>            Reporter: Fan Jiang
>            Assignee: Fan Jiang
>              Labels: features
>
> In recent years, spectral clustering has become one of the most popular modern clustering algorithms. It is simple to implement, can be solved efficiently by standard linear algebra software, and very often outperforms traditional clustering algorithms such as the k-means algorithm.
> Power iteration clustering is a scalable and efficient algorithm for clustering points given pointwise mutual affinity values.  Internally the algorithm:
> computes the Gaussian distance between all pairs of points and represents these distances in an Affinity Matrix
> calculates a Normalized Affinity Matrix
> calculates the principal eigenvalue and eigenvector
> Clusters each of the input points according to their principal eigenvector component value
> Details of this algorithm are found within [Power Iteration Clustering, Lin and Cohen]{www.icml2010.org/papers/387.pdf}



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