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# What is the diference between Bregman Divergence Mahalanobis Distance and Mahalanobis Distance?

Member Posts: 3 Contributor I
edited December 2018 in Help

Hi, I'm a beginner in RapidMiner Studio. I'm working with clustering operators (k-means and k-medoid) and I want to know what is the diference between the Mahalanobis Distance (https://en.wikipedia.org/wiki/Mahalanobis_distance) and the option in the parameters of the operator which says "Bregman divergences" and the sub-option divergence: "Mahalanobis distance". I don't know if they are the same or not.

## Best Answers

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Member Posts: 333 Unicorn
Solution Accepted

Hi,

Perhaps these slides might explain your question?

Cheers

Sven

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Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,524 RM Data Scientist
Solution Accepted

Hi @agucaba123,

here is what we do:

`	@Override	public double calculateDistance(double[] value1, double[] value2) {		Matrix x = new Matrix(value1, value1.length);		Matrix y = new Matrix(value2, value2.length);		Matrix deltaxy = x.minus(y);		// compute the mahalanobis distance		return Math.sqrt(deltaxy.transpose().times(inverseCovariance).times(deltaxy).get(0, 0));	}`

Does this make sense?

BR,

Martin

- Sr. Director Data Solutions, Altair RapidMiner -
Dortmund, Germany
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