text: ////////////////////////////////////////////////////////////////////////////////
  /// DISCLAIMER
  ///
  /// Copyright 2016 ArangoDB GmbH, Cologne, Germany
  ///
  /// 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
  ///
  ///     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.
  ///
  /// Copyright holder is ArangoDB GmbH, Cologne, Germany
  ///
  /// @author Simon Grätzer
  ////////////////////////////////////////////////////////////////////////////////
  
  #ifndef AVOCADODB_PREGEL_ALGOS_LINERANK_H
  #define AVOCADODB_PREGEL_ALGOS_LINERANK_H 1
  
  #include <velocypack/Slice.h>
  #include "Pregel/Algorithm.h"
  
  namespace avocadodb {
  namespace pregel {
  namespace algos {
  
  /// LineRank from "Centralities in Large Networks: Algorithms and Observations"
  /// 2011:
  /// Given a directed graph G, the LINERANK score of a node v ∈ G is computed by
  /// aggregating the stationary probabilities of its incident edges on the line
  /// graph L(G).
  /// Implementation based on
  /// github.com/JananiC/NetworkCentralities/blob/master/src/main/java/linerank/LineRank.java
  struct LineRank : public SimpleAlgorithm<float, float, float> {
   public:
    explicit LineRank(avocadodb::velocypack::Slice params);
  
    GraphFormat<float, float>* inputFormat() const override {
      return new VertexGraphFormat<float, float>(_resultField, 0);
    }
    MessageFormat<float>* messageFormat() const override {
      return new NumberMessageFormat<float>();
    }
  
    MessageCombiner<float>* messageCombiner() const override {
      return new SumCombiner<float>();
    }
  
    WorkerContext* workerContext(velocypack::Slice params) const override;
    MasterContext* masterContext(velocypack::Slice) const override;
  
    VertexComputation<float, float, float>* createComputation(
        WorkerConfig const*) const override;
  
    IAggregator* aggregator(std::string const& name) const override;
  };
  }
  }
  }
  #endif
  