content: /*
   * Tencent is pleased to support the open source community by making Angel available.
   *
   * Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
   *
   * 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
   *
   * https://opensource.org/licenses/Apache-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 com.tencent.angel.sona.tree.objective.metric;
  
  import javax.inject.Singleton;
  
  @Singleton
  public class RMSEMetric extends AverageEvalMetric {
      private static RMSEMetric instance;
  
      private RMSEMetric() {}
  
      @Override
      public Kind getKind() {
          return Kind.RMSE;
      }
  
      @Override
      public double evalOne(float pred, float label) {
          double diff = pred - label;
          return diff * diff;
      }
  
      @Override
      public double evalOne(float[] pred, float label) {
          double err = 0.0;
          int trueLabel = (int) label;
          for (int i = 0; i < pred.length; i++) {
              double diff = pred[i] - (i == trueLabel ? 1 : 0);
              err += diff * diff;
          }
          return err;
      }
  
      public static RMSEMetric getInstance() {
          if (instance == null)
              instance = new RMSEMetric();
          return instance;
      }
  }
  