mahout常用距离一览表

mahout常用DistanceMeasure一览表:

org.apache.mahout.common.distance.ChebyshevDistanceMeasure;
org.apache.mahout.common.distance.CosineDistanceMeasure;
org.apache.mahout.common.distance.EuclideanDistanceMeasure;
org.apache.mahout.common.distance.MahalanobisDistanceMeasure;
org.apache.mahout.common.distance.ManhattanDistanceMeasure;
org.apache.mahout.common.distance.MinkowskiDistanceMeasure;
org.apache.mahout.common.distance.SquaredEuclideanDistanceMeasure;
org.apache.mahout.common.distance.TanimotoDistanceMeasure;
org.apache.mahout.common.distance.WeightedEuclideanDistanceMeasure;
org.apache.mahout.common.distance.WeightedManhattanDistanceMeasure;

 比较常用的有两个欧氏距离和余弦

CosineDistanceMeasure：

 EuclideanDistanceMeasure：

 EuclideanDistanceMeasure和CosineDistanceMeasure区别见图：

 其中有两个基于权重的距离计算方法：

org.apache.mahout.common.distance.WeightedEuclideanDistanceMeasure;
org.apache.mahout.common.distance.WeightedManhattanDistanceMeasure;

 使用方式如下：

WeightedManhattanDistanceMeasure cdm = new WeightedManhattanDistanceMeasure();
cdm.setWeights(new DenseVector(new double[] {1, 2, 3 }));
System.out.println(cdm.distance(new DenseVector(new double[] {0.11, 510, 10 }),
	new DenseVector(new double[] {0.11, 510, 1 })));

 设置weight即可