edu.snu.cms.reef.ml.kmeans.data.EuclideanDistance.java Source code

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Here is the source code for edu.snu.cms.reef.ml.kmeans.data.EuclideanDistance.java

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/**
 * Copyright (C) 2014 Seoul National University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package edu.snu.cms.reef.ml.kmeans.data;

import org.apache.mahout.math.Vector;

import javax.inject.Inject;

/**
 * Implements DistanceMeasure (Default)
 */
public final class EuclideanDistance implements VectorDistanceMeasure {

    @Inject
    public EuclideanDistance() {
    }

    @Override
    public final double distance(Vector v1, Vector v2) {
        if (v1.size() != v2.size()) {
            throw new IllegalArgumentException("Vector dimensions are not consistent");
        }

        double distance = 0;
        for (int i = 0; i < v1.size(); i++) {
            distance += (v1.get(i) - v2.get(i)) * (v1.get(i) - v2.get(i));
        }
        return Math.sqrt(distance);
    }
}