mirror of
https://github.com/ceres-solver/ceres-solver.git
synced 2026-08-29 16:40:38 +08:00
Keir Mierle
7492b0d8de
Since Ceres is moving to using GitHub for issues, and the Google Code URL in the current copyright header will soon become invalid, update all the headers. Change-Id: I1fce70375d1bcf098591f07b4d8f01a5c1e0789c
111 lines
3.8 KiB
C++
111 lines
3.8 KiB
C++
// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2015 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: sameeragarwal@google.com (Sameer Agarwal)
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// This include must come before any #ifndef check on Ceres compile options.
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#include "ceres/internal/port.h"
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#ifndef CERES_NO_SUITESPARSE
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#include "ceres/single_linkage_clustering.h"
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#include "ceres/graph.h"
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#include "ceres/collections_port.h"
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#include "ceres/graph_algorithms.h"
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namespace ceres {
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namespace internal {
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int ComputeSingleLinkageClustering(
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const SingleLinkageClusteringOptions& options,
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const WeightedGraph<int>& graph,
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HashMap<int, int>* membership) {
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CHECK_NOTNULL(membership)->clear();
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// Initially each vertex is in its own cluster.
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const HashSet<int>& vertices = graph.vertices();
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for (HashSet<int>::const_iterator it = vertices.begin();
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it != vertices.end();
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++it) {
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(*membership)[*it] = *it;
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}
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for (HashSet<int>::const_iterator it1 = vertices.begin();
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it1 != vertices.end();
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++it1) {
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const int vertex1 = *it1;
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const HashSet<int>& neighbors = graph.Neighbors(vertex1);
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for (HashSet<int>::const_iterator it2 = neighbors.begin();
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it2 != neighbors.end();
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++it2) {
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const int vertex2 = *it2;
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// Since the graph is undirected, only pay attention to one side
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// of the edge and ignore weak edges.
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if ((vertex1 > vertex2) ||
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(graph.EdgeWeight(vertex1, vertex2) < options.min_similarity)) {
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continue;
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}
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// Use a union-find algorithm to keep track of the clusters.
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const int c1 = FindConnectedComponent(vertex1, membership);
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const int c2 = FindConnectedComponent(vertex2, membership);
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if (c1 == c2) {
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continue;
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}
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if (c1 < c2) {
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(*membership)[c2] = c1;
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} else {
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(*membership)[c1] = c2;
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}
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}
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}
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// Make sure that every vertex is connected directly to the vertex
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// identifying the cluster.
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int num_clusters = 0;
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for (HashMap<int, int>::iterator it = membership->begin();
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it != membership->end();
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++it) {
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it->second = FindConnectedComponent(it->first, membership);
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if (it->first == it->second) {
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++num_clusters;
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}
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}
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return num_clusters;
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}
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} // namespace internal
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} // namespace ceres
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#endif // CERES_NO_SUITESPARSE
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