internal/ceres/single_linkage_clustering.h

// 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 <unordered_map>

#include "ceres/graph.h"
#include "ceres/internal/port.h"

namespace ceres {
namespace internal {

struct SingleLinkageClusteringOptions {
  // Graph edges with edge weight less than min_similarity are ignored
  // during the clustering process.
  double min_similarity = 0.99;
};

// 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 CERES_EXPORT_INTERNAL
ComputeSingleLinkageClustering(const SingleLinkageClusteringOptions& options,
                               const WeightedGraph<int>& graph,
                               std::unordered_map<int, int>* membership);

}  // namespace internal
}  // namespace ceres

#endif  // CERES_INTERNAL_SINGLE_LINKAGE_CLUSTERING_H_