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.ml.GBDT.algo;
  
  import com.tencent.angel.ml.GBDT.algo.RegTree.GradHistHelper;
  import com.tencent.angel.ml.math2.vector.IntDoubleVector;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import java.util.Arrays;
  import java.util.concurrent.Callable;
  
  public class HistCalThread implements Callable<Boolean> {
  
    private static final Log LOG = LogFactory.getLog(HistCalThread.class);
  
    private GBDTController controller;
    private int nid;
    private int start;
    private int end;
  
    public HistCalThread(GBDTController controller, int nid, int start, int end) {
      this.controller = controller;
      this.nid = nid;
      this.start = start;
      this.end = end;
    }
  
    @Override public Boolean call() throws Exception {
      GradHistHelper histMaker = new GradHistHelper(this.controller, this.nid);
      IntDoubleVector localHist = histMaker.buildHistogram(start, end);
      LOG.debug(String.format("Batch histogram[%d]: %s", nid,
        Arrays.toString(localHist.get(new int[] {0, 1, 2, 3, 4, 5}))));
      synchronized (this) {
        this.controller.histCache[nid].iadd(localHist);
        LOG.debug(String.format("Calculated histogram[%d]: %s", nid,
          Arrays.toString(this.controller.histCache[nid].get(new int[] {0, 1, 2, 3, 4, 5}))));
      }
      return true;
    }
  }
  