// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

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// Author: sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_

#define CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_

#include "ceres/collections_port.h"

#include "ceres/graph.h"

namespace ceres {

namespace internal {

struct SingleLinkageClusteringOptions {

  SingleLinkageClusteringOptions()

      : min_similarity(0.99) {

  }

  // Graph edges with edge weight less than min_similarity are ignored

  // during the clustering process.

  double min_similarity;

};

// Compute a partitioning of the vertices of the graph using the

// single linkage clustering algorithm. Edges with weight less than

// SingleLinkageClusteringOptions::min_similarity will be ignored.

//

// membership upon return will contain a mapping from the vertices of

// the graph to an integer indicating the identity of the cluster that

// it belongs to.

//

// The return value of this function is the number of clusters

// identified by the algorithm.

int ComputeSingleLinkageClustering(

    const SingleLinkageClusteringOptions& options,

    const WeightedGraph<int>& graph,

    HashMap<int, int>* membership);

}  // namespace internal

}  // namespace ceres

#endif  // CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_