METISOrderingExample.cpp

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/* ----------------------------------------------------------------------------
 
 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)
 
 * See LICENSE for the license information
 
 * -------------------------------------------------------------------------- */
 
#include <gtsam/geometry/Pose2.h>
#include <gtsam/nonlinear/LevenbergMarquardtOptimizer.h>
#include <gtsam/nonlinear/Marginals.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/Values.h>
#include <gtsam/slam/BetweenFactor.h>
 
using namespace std;
using namespace gtsam;
 
int main(int argc, char** argv) {
  NonlinearFactorGraph graph;
 
  Pose2 priorMean(0.0, 0.0, 0.0);  // prior at origin
  auto priorNoise = noiseModel::Diagonal::Sigmas(Vector3(0.3, 0.3, 0.1));
  graph.addPrior(1, priorMean, priorNoise);
 
  Pose2 odometry(2.0, 0.0, 0.0);
  auto odometryNoise = noiseModel::Diagonal::Sigmas(Vector3(0.2, 0.2, 0.1));
  graph.emplace_shared<BetweenFactor<Pose2> >(1, 2, odometry, odometryNoise);
  graph.emplace_shared<BetweenFactor<Pose2> >(2, 3, odometry, odometryNoise);
  graph.print("\nFactor Graph:\n");  // print
 
  Values initial;
  initial.insert(1, Pose2(0.5, 0.0, 0.2));
  initial.insert(2, Pose2(2.3, 0.1, -0.2));
  initial.insert(3, Pose2(4.1, 0.1, 0.1));
  initial.print("\nInitial Estimate:\n");  // print
 
  // optimize using Levenberg-Marquardt optimization
  LevenbergMarquardtParams params;
  // In order to specify the ordering type, we need to se the "orderingType". By
  // default this parameter is set to OrderingType::COLAMD
  params.orderingType = Ordering::METIS;
  LevenbergMarquardtOptimizer optimizer(graph, initial, params);
  Values result = optimizer.optimize();
  result.print("Final Result:\n");
 
  return 0;
}