Clustering and the K-means algorithm
Yihui Saw18.304 Seminar Talk I
March 6, 2013
Saturday, March 16, 13
Clustering examples
• Customer purchase patterns
• Language family models
• Data compression
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Original Image
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2 colors
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4 colors
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8 colors
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The clustering problem
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Distance metric
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The cost of clustering
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K-means algorithm
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K-means algorithm
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K-means algorithm
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K-means algorithm
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K-means algorithm
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K-means algorithm
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Proof of convergence• Each iterative step necessarily lowers the
cost - the cost monotonically decrease
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Proof of convergence• Each iterative step necessarily lowers the
cost - the cost monotonically decrease
]
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Convergence to local minimum
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Convergence to local minimum
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Convergence to local minimum
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Convergence to local minimum
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Convergence to local minimum
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Convergence to local minimum
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Convergence to local minimum
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