org.apache.mahout.common.distance
Class EuclideanDistanceMeasure
java.lang.Object
org.apache.mahout.common.distance.SquaredEuclideanDistanceMeasure
org.apache.mahout.common.distance.EuclideanDistanceMeasure
- All Implemented Interfaces:
- DistanceMeasure, Parametered
public class EuclideanDistanceMeasure
- extends SquaredEuclideanDistanceMeasure
This class implements a Euclidean distance metric by summing the square root of the squared differences
between each coordinate.
If you don't care about the true distance and only need the values for comparison, then the base class,
SquaredEuclideanDistanceMeasure
, will be faster since it doesn't do the actual square root of the
squared differences.
Fields inherited from interface org.apache.mahout.common.parameters.Parametered |
log |
Method Summary |
double |
distance(double centroidLengthSquare,
Vector centroid,
Vector v)
Optimized version of distance metric for sparse vectors. |
double |
distance(Vector v1,
Vector v2)
Returns the distance metric applied to the arguments |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
EuclideanDistanceMeasure
public EuclideanDistanceMeasure()
distance
public double distance(Vector v1,
Vector v2)
- Description copied from interface:
DistanceMeasure
- Returns the distance metric applied to the arguments
- Specified by:
distance
in interface DistanceMeasure
- Overrides:
distance
in class SquaredEuclideanDistanceMeasure
- Parameters:
v1
- a Vector defining a multidimensional point in some feature spacev2
- a Vector defining a multidimensional point in some feature space
- Returns:
- a scalar doubles of the distance
distance
public double distance(double centroidLengthSquare,
Vector centroid,
Vector v)
- Description copied from interface:
DistanceMeasure
- Optimized version of distance metric for sparse vectors. This distance computation requires operations
proportional to the number of non-zero elements in the vector instead of the cardinality of the vector.
- Specified by:
distance
in interface DistanceMeasure
- Overrides:
distance
in class SquaredEuclideanDistanceMeasure
- Parameters:
centroidLengthSquare
- Square of the length of centroidcentroid
- Centroid vector
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