143 lines
4.7 KiB
C++
143 lines
4.7 KiB
C++
/* ----------------------------------------------------------------------------
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* GTSAM Copyright 2010, Georgia Tech Research Corporation,
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* Atlanta, Georgia 30332-0415
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* All Rights Reserved
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* Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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* See LICENSE for the license information
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* -------------------------------------------------------------------------- */
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/**
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* @file SFMExample_bal_COLAMD_METIS.cpp
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* @brief This file is to compare the ordering performance for COLAMD vs METIS.
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* Example problem is to solve a structure-from-motion problem from a "Bundle Adjustment in the Large" file.
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* @author Frank Dellaert, Zhaoyang Lv
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*/
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// For an explanation of headers, see SFMExample.cpp
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#include <gtsam/inference/Symbol.h>
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#include <gtsam/inference/Ordering.h>
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#include <gtsam/nonlinear/NonlinearFactorGraph.h>
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#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
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#include <gtsam/slam/GeneralSFMFactor.h>
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#include <gtsam/slam/dataset.h> // for loading BAL datasets !
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#include <gtsam/base/timing.h>
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#include <vector>
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using namespace std;
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using namespace gtsam;
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using symbol_shorthand::C;
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using symbol_shorthand::P;
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// We will be using a projection factor that ties a SFM_Camera to a 3D point.
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// An SFM_Camera is defined in datase.h as a camera with unknown Cal3Bundler
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// calibration and has a total of 9 free parameters
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typedef GeneralSFMFactor<SfmCamera, Point3> MyFactor;
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int main(int argc, char* argv[]) {
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// Find default file, but if an argument is given, try loading a file
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string filename = findExampleDataFile("dubrovnik-3-7-pre");
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if (argc > 1) filename = string(argv[1]);
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// Load the SfM data from file
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SfmData mydata;
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readBAL(filename, mydata);
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cout << boost::format("read %1% tracks on %2% cameras\n") %
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mydata.numberTracks() % mydata.numberCameras();
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// Create a factor graph
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NonlinearFactorGraph graph;
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// We share *one* noiseModel between all projection factors
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auto noise = noiseModel::Isotropic::Sigma(2, 1.0); // one pixel in u and v
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// Add measurements to the factor graph
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size_t j = 0;
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for (const SfmTrack& track : mydata.tracks) {
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for (const SfmMeasurement& m : track.measurements) {
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size_t i = m.first;
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Point2 uv = m.second;
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graph.emplace_shared<MyFactor>(
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uv, noise, C(i), P(j)); // note use of shorthand symbols C and P
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}
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j += 1;
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}
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// Add a prior on pose x1. This indirectly specifies where the origin is.
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// and a prior on the position of the first landmark to fix the scale
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graph.addPrior(C(0), mydata.cameras[0], noiseModel::Isotropic::Sigma(9, 0.1));
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graph.addPrior(P(0), mydata.tracks[0].p,
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noiseModel::Isotropic::Sigma(3, 0.1));
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// Create initial estimate
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Values initial;
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size_t i = 0;
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j = 0;
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for (const SfmCamera& camera : mydata.cameras) initial.insert(C(i++), camera);
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for (const SfmTrack& track : mydata.tracks) initial.insert(P(j++), track.p);
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/** --------------- COMPARISON -----------------------**/
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/** ----------------------------------------------------**/
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LevenbergMarquardtParams params_using_COLAMD, params_using_METIS;
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try {
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params_using_METIS.setVerbosity("ERROR");
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gttic_(METIS_ORDERING);
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params_using_METIS.ordering = Ordering::Create(Ordering::METIS, graph);
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gttoc_(METIS_ORDERING);
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params_using_COLAMD.setVerbosity("ERROR");
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gttic_(COLAMD_ORDERING);
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params_using_COLAMD.ordering = Ordering::Create(Ordering::COLAMD, graph);
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gttoc_(COLAMD_ORDERING);
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} catch (exception& e) {
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cout << e.what();
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}
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// expect they have different ordering results
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if (params_using_COLAMD.ordering == params_using_METIS.ordering) {
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cout << "COLAMD and METIS produce the same ordering. "
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<< "Problem here!!!" << endl;
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}
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/* Optimize the graph with METIS and COLAMD and time the results */
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Values result_METIS, result_COLAMD;
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try {
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gttic_(OPTIMIZE_WITH_METIS);
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LevenbergMarquardtOptimizer lm_METIS(graph, initial, params_using_METIS);
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result_METIS = lm_METIS.optimize();
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gttoc_(OPTIMIZE_WITH_METIS);
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gttic_(OPTIMIZE_WITH_COLAMD);
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LevenbergMarquardtOptimizer lm_COLAMD(graph, initial, params_using_COLAMD);
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result_COLAMD = lm_COLAMD.optimize();
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gttoc_(OPTIMIZE_WITH_COLAMD);
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} catch (exception& e) {
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cout << e.what();
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}
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{ // printing the result
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cout << "COLAMD final error: " << graph.error(result_COLAMD) << endl;
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cout << "METIS final error: " << graph.error(result_METIS) << endl;
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cout << endl << endl;
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cout << "Time comparison by solving " << filename << " results:" << endl;
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cout << boost::format("%1% point tracks and %2% cameras\n") %
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mydata.numberTracks() % mydata.numberCameras()
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<< endl;
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tictoc_print_();
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}
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return 0;
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}
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