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.graph.client.sampleFeats;
  
  import com.tencent.angel.graph.client.getnodefeats2.PartGetNodeFeatsResult;
  import com.tencent.angel.graph.data.Node;
  import com.tencent.angel.ml.math2.vector.IntFloatVector;
  import com.tencent.angel.ml.matrix.psf.get.base.GetFunc;
  import com.tencent.angel.ml.matrix.psf.get.base.GetResult;
  import com.tencent.angel.ml.matrix.psf.get.base.PartitionGetParam;
  import com.tencent.angel.ml.matrix.psf.get.base.PartitionGetResult;
  import com.tencent.angel.ps.storage.vector.ServerLongAnyRow;
  import com.tencent.angel.ps.storage.vector.element.IElement;
  import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
  import it.unimi.dsi.fastutil.objects.ObjectIterator;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Random;
  
  public class SampleNodeFeats extends GetFunc {
  
    public SampleNodeFeats(SampleNodeFeatsParam param) {
      super(param);
    }
  
    public SampleNodeFeats() {
      this(null);
    }
  
    @Override
    public PartitionGetResult partitionGet(PartitionGetParam partParam) {
      SampleNodeFeatsPartParam param = (SampleNodeFeatsPartParam) partParam;
      ServerLongAnyRow row = (ServerLongAnyRow) psContext.getMatrixStorageManager()
          .getRow(param.getPartKey(), 0);
  
      int size = Math.min(row.size(), param.getSize());
      IntFloatVector[] feats = new IntFloatVector[size];
      Random rand = new Random(System.currentTimeMillis());
      // sample continuously beginning from a random index
      int bound = row.size() - size;
      int skip = bound > 0 ? rand.nextInt(bound) : 0;
      ObjectIterator<Long2ObjectMap.Entry<IElement>> it = row.getStorage().iterator();
      it.skip(skip);
      for (int i = 0; i < size; i++) {
        feats[i] = ((Node) it.next().getValue()).getFeats();
      }
  
      return new PartGetNodeFeatsResult(param.getPartKey().getPartitionId(), feats);
    }
  
    @Override
    public GetResult merge(List<PartitionGetResult> partResults) {
      List<IntFloatVector> results = new ArrayList<>();
      for (PartitionGetResult partResult : partResults) {
        results.addAll(Arrays.asList(((PartGetNodeFeatsResult) partResult).getFeats()));
      }
      return new SampleNodeFeatsResult(results);
    }
  }
  