calculating gini index

Question

I want to what type of Gini coeffcient used in item distribution and what is the formula to calculate Gini coeffcient and Gini index

MartinLiebig · Accepted Answer

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

2015228094 · Accepted Answer

Thank you

Is this formula used for clustring kmean evalution?

do you have the formula as mathematical equation?

MartinLiebig · Accepted Answer

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