timeDSFvariants.cpp

Go to the documentation of this file.

/* ----------------------------------------------------------------------------

 * 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/base/timing.h>
#include <gtsam/base/DSFVector.h>
#include <gtsam_unstable/base/DSF.h>
#include <gtsam/base/DSFMap.h>

#include <fstream>
#include <iostream>
#include <random>
#include <vector>
#include <utility>

using namespace std;
using namespace gtsam;

int main(int argc, char* argv[]) {

  // Create CSV file for results
  ofstream os("dsf-timing.csv");
  os << "images,points,matches,Base,Map,BTree" << endl;

  // loop over number of images
  vector<size_t> ms {10, 20, 30, 40, 50, 100, 200, 300, 400, 500, 1000};
  for(size_t m: ms) {
    // We use volatile here to make these appear to the optimizing compiler as
    // if their values are only known at run-time.
    volatile size_t n = 500; // number of points per image
    volatile size_t N = m * n; // number of points per image

    volatile double fm = 0.1; // fraction of image pairs matched
    volatile size_t np = fm * m * m / 2; // number of image pairs
    volatile double fpm = 0.5; // fraction of points matched
    volatile size_t nm = fpm * n * np; // number of matches

    cout << "\nTesting with " << (int)m << " images, " << (int)N << " points, " << (int)nm << " matches\n";
    cout << "Generating " << nm << " matches" << endl;
    std::mt19937 rng;
    std::uniform_int_distribution<> rn(0, N - 1);

    typedef pair<size_t, size_t> Match;
    vector<Match> matches;
    matches.reserve(nm);
    for (size_t k = 0; k < nm; k++)
      matches.push_back(Match(rn(rng), rn(rng)));

    os << (int)m << "," << (int)N << "," << (int)nm << ",";

    {
      // DSFBase version
      double dsftime = 0;
      gttic_(dsftime);
      DSFBase dsf(N); // Allow for N keys
      for(const Match& m: matches)
        dsf.merge(m.first, m.second);
      gttoc_(dsftime);
      tictoc_getNode(dsftimeNode, dsftime);
      dsftime = dsftimeNode->secs();
      os << dsftime << ",";
      cout << "DSFBase: " << dsftime << " s" << endl;
      tictoc_reset_();
    }

    {
      // DSFMap version
      double dsftime = 0;
      gttic_(dsftime);
      DSFMap<size_t> dsf;
      for(const Match& m: matches)
        dsf.merge(m.first, m.second);
      gttoc_(dsftime);
      tictoc_getNode(dsftimeNode, dsftime);
      dsftime = dsftimeNode->secs();
      os << dsftime << endl;
      cout << "DSFMap: " << dsftime << " s" << endl;
      tictoc_reset_();
    }

    if (false) {
      // DSF version, functional
      double dsftime = 0;
      gttic_(dsftime);
      DSF<size_t> dsf;
      for (size_t j = 0; j < N; j++)
        dsf = dsf.makeSet(j);
      for(const Match& m: matches)
        dsf = dsf.makeUnion(m.first, m.second);
      gttoc_(dsftime);
      tictoc_getNode(dsftimeNode, dsftime);
      dsftime = dsftimeNode->secs();
      os << dsftime << endl;
      cout << "DSF functional: " << dsftime << " s" << endl;
      tictoc_reset_();
    }

    if (false) {
      // DSF version, in place - always slower - use functional !
      double dsftime = 0;
      gttic_(dsftime);
      DSF<size_t> dsf;
      for (size_t j = 0; j < N; j++)
        dsf.makeSetInPlace(j);
      for(const Match& m: matches)
        dsf.makeUnionInPlace(m.first, m.second);
      gttoc_(dsftime);
      tictoc_getNode(dsftimeNode, dsftime);
      dsftime = dsftimeNode->secs();
      os << dsftime << ",";
      cout << "DSF in-place: " << dsftime << " s" << endl;
      tictoc_reset_();
    }

  }

  return 0;

}