opennlp.maxent.quasinewton.ArrayMath Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of opennlp-maxent Show documentation

The newest version!

/*
 * 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.
 */
package opennlp.maxent.quasinewton;

/**
 * utility class for simple vector arithmetics.
 */
public class ArrayMath {

  public static double innerProduct(double[] vecA, double[] vecB) {
    if (vecA == null || vecB == null) 
      return Double.NaN;
    if (vecA.length != vecB.length)
      return Double.NaN;

    double product = 0.0;
    for (int i = 0; i < vecA.length; i++) {
      product += vecA[i] * vecB[i];
    }
    return product;
  }

  public static double[] updatePoint(double[] point, double[] vector, double scale) {
    if (point == null || vector == null)
      return null;
    if (point.length != vector.length)
      return null;

    double[] updated = point.clone();
    for (int i = 0; i < updated.length; i++) {
      updated[i] = updated[i] + (vector[i] * scale);
    }
    return updated;
  }
}