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.psf.hyperanf;
  
  import com.tencent.angel.ml.matrix.psf.aggr.enhance.UnaryAggrFunc;
  import com.tencent.angel.ps.storage.vector.ServerLongAnyRow;
  import com.tencent.angel.ps.storage.vector.ServerRow;
  import com.tencent.angel.ps.storage.vector.element.IElement;
  import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
  import it.unimi.dsi.fastutil.objects.ObjectIterator;
  
  public class MaxCardinality extends UnaryAggrFunc {
  
    public MaxCardinality(int matrixId, int rowId) {
      super(matrixId, rowId);
    }
  
    public MaxCardinality() {
      super(-1, -1);
    }
  
    @Override
    public double processRow(ServerRow row) {
      double maxCardinality = 0;
      ObjectIterator<Long2ObjectMap.Entry<IElement>> it = ((ServerLongAnyRow) row).iterator();
      while (it.hasNext()) {
        maxCardinality = Math
                .max(maxCardinality, ((HyperLogLogPlusElement) it.next().getValue()).getCardinality());
      }
      return maxCardinality;
    }
  
    @Override
    public double mergeOp(double a, double b) {
      return Math.max(a, b);
    }
  
    @Override
    public double mergeInit() {
      return 0;
    }
  }
  