calculating gini index

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  MartinLiebig Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,510 RM Data Scientist

  January 2018 Solution Accepted

  Hi,

   

  the one used in Trees and Weight By Gini can be found here:

   

  https://github.com/rapidminer/rapidminer-studio/blob/master/src/main/java/com/rapidminer/operator/learner/tree/criterions/GiniIndexCriterion.java

   

  Best,

  Martin

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

  1
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  2015228094 Member Posts: 3 Contributor I

  January 2018 Solution Accepted

  Thank you

  Is this formula used for clustring kmean evalution?

  do you have the formula as mathematical equation?

  0
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  MartinLiebig Administrator, Moderator, Employee, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,510 RM Data Scientist

  January 2018 Solution Accepted

  Hi,

   

  for clustering its: https://github.com/rapidminer/rapidminer-studio/blob/master/src/main/java/com/rapidminer/operator/validation/clustering/exampledistribution/GiniCoefficient.java

  or in code

  		double sum = 0;
  		for (int i = 0; i < x.length; i++) {
  			sum = sum + x[i];
  		}
  
  		double mean = sum / n;
  
  		sum = 0;
  		for (int i = 0; i < x.length; i++) {
  			for (int j = 0; j < x.length; j++) {
  				sum = sum + Math.abs(x[i] - x[j]);
  			}
  		}
  
  		if (mean == 0) {
  			return 0.0;
  		}
  
  		return 1 - (sum / (2 * mean * (n * ((double) n - 1))));

   

  Best,

  Martin

   

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

  1