content: package org.apache.solr.search.function.distance;
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.
   */
  
  import org.apache.lucene.spatial.DistanceUtils;
  import org.apache.solr.search.function.DocValues;
  import org.apache.solr.search.function.MultiValueSource;
  
  
  /**
   * While not strictly a distance, the Sq. Euclidean Distance is often all that is needed in many applications
   * that require a distance, thus saving a sq. rt. calculation
   */
  public class SquaredEuclideanFunction extends VectorDistanceFunction {
    protected String name = "sqedist";
  
    public SquaredEuclideanFunction(MultiValueSource source1, MultiValueSource source2) {
      super(-1, source1, source2);//overriding distance, so power doesn't matter here
    }
  
  
    @Override
    protected String name() {
  
      return name;
    }
  
    /**
     * @param doc The doc to score
     */
    @Override
    protected double distance(int doc, DocValues dv1, DocValues dv2) {
  
      double[] vals1 = new double[source1.dimension()];
      double[] vals2 = new double[source1.dimension()];
      dv1.doubleVal(doc, vals1);
      dv2.doubleVal(doc, vals2);
  
      return DistanceUtils.squaredEuclideanDistance(vals1, vals2);
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) return true;
      if (!(o instanceof SquaredEuclideanFunction)) return false;
      if (!super.equals(o)) return false;
  
      SquaredEuclideanFunction that = (SquaredEuclideanFunction) o;
  
      if (!name.equals(that.name)) return false;
  
      return true;
    }
  
    @Override
    public int hashCode() {
      int result = super.hashCode();
      result = 31 * result + name.hashCode();
      return result;
    }
  }
  