// g2o - General Graph Optimization
// Copyright (C) 2011 R. Kuemmerle, G. Grisetti, W. Burgard
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the distribution.
//
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#include "optimization_algorithm_gauss_newton.h"

#include <cassert>

#include "batch_stats.h"
#include "g2o/stuff/logger.h"
#include "g2o/stuff/timeutil.h"
#include "solver.h"
#include "sparse_optimizer.h"

using namespace std;

namespace g2o {

OptimizationAlgorithmGaussNewton::OptimizationAlgorithmGaussNewton(
    std::unique_ptr<Solver> solver)
    : OptimizationAlgorithmWithHessian(*solver.get()),
      m_solver{std::move(solver)} {}

OptimizationAlgorithmGaussNewton::~OptimizationAlgorithmGaussNewton() {}

OptimizationAlgorithm::SolverResult OptimizationAlgorithmGaussNewton::solve(
    int iteration, bool online) {
  assert(_solver.optimizer() == _optimizer &&
         "underlying linear solver operates on different graph");
  bool ok = true;

  // here so that correct component for max-mixtures can be computed before the
  // build structure
  double t = get_monotonic_time();
  _optimizer->computeActiveErrors();
  G2OBatchStatistics* globalStats = G2OBatchStatistics::globalStats();
  if (globalStats) {
    globalStats->timeResiduals = get_monotonic_time() - t;
  }

  if (iteration == 0 &&
      !online) {  // built up the CCS structure, here due to easy time measure
    ok = _solver.buildStructure();
    if (!ok) {
      G2O_WARN("Failure while building CCS structure");
      return OptimizationAlgorithm::Fail;
    }
  }

  t = get_monotonic_time();
  _solver.buildSystem();
  if (globalStats) {
    globalStats->timeQuadraticForm = get_monotonic_time() - t;
    t = get_monotonic_time();
  }

  ok = _solver.solve();
  if (globalStats) {
    globalStats->timeLinearSolution = get_monotonic_time() - t;
    t = get_monotonic_time();
  }

  _optimizer->update(_solver.x());
  if (globalStats) {
    globalStats->timeUpdate = get_monotonic_time() - t;
  }
  if (ok)
    return OK;
  else
    return Fail;
}

void OptimizationAlgorithmGaussNewton::printVerbose(std::ostream& os) const {
  os << "\t schur= " << _solver.schur();
}

}  // namespace g2o
