bool solve_translations_problem_l2_chordal
(
const int* edges,
const double* poses,
const double* weights,
int num_edges,
double loss_width,
double* X,
double function_tolerance,
double parameter_tolerance,
int max_iterations
)
{
// seed the random number generator
std::srand( std::time( NULL ) );
// re index the edges to be a sequential set
std::vector<int> reindexed_edges(edges, edges+2*num_edges);
std::vector<int> reindexed_lookup;
reindex_problem(&reindexed_edges[0], num_edges, reindexed_lookup);
const int num_nodes = reindexed_lookup.size();
// Init with a random guess solution
std::vector<double> x(3*num_nodes);
for (int i=0; i<3*num_nodes; ++i)
x[i] = (double)rand() / RAND_MAX;
// add the parameter blocks (a 3-vector for each node)
Problem problem;
for (int i=0; i<num_nodes; ++i)
problem.AddParameterBlock(&x[3*i], 3);
// set the residual function (chordal distance for each edge)
for (int i=0; i<num_edges; ++i) {
CostFunction* cost_function =
new AutoDiffCostFunction<ChordFunctor, 3, 3, 3>(
new ChordFunctor(poses+3*i, weights[i]));
if (loss_width == 0.0) {
// No robust loss function
problem.AddResidualBlock(cost_function, NULL, &x[3*reindexed_edges[2*i+0]], &x[3*reindexed_edges[2*i+1]]);
} else {
problem.AddResidualBlock(cost_function, new ceres::HuberLoss(loss_width), &x[3*reindexed_edges[2*i+0]], &x[3*reindexed_edges[2*i+1]]);
}
}
// Fix first camera in {0,0,0}: fix the translation ambiguity
x[0] = x[1] = x[2] = 0.0;
problem.SetParameterBlockConstant(&x[0]);
// solve
Solver::Options options;
#ifdef OPENMVG_USE_OPENMP
options.num_threads = omp_get_max_threads();
options.num_linear_solver_threads = omp_get_max_threads();
#endif // OPENMVG_USE_OPENMP
options.minimizer_progress_to_stdout = false;
options.logging_type = ceres::SILENT;
options.max_num_iterations = max_iterations;
options.function_tolerance = function_tolerance;
options.parameter_tolerance = parameter_tolerance;
// Since the problem is sparse, use a sparse solver iff available
if (ceres::IsSparseLinearAlgebraLibraryTypeAvailable(ceres::SUITE_SPARSE))
{
options.sparse_linear_algebra_library_type = ceres::SUITE_SPARSE;
options.linear_solver_type = ceres::SPARSE_NORMAL_CHOLESKY;
}
else if (ceres::IsSparseLinearAlgebraLibraryTypeAvailable(ceres::CX_SPARSE))
{
options.sparse_linear_algebra_library_type = ceres::CX_SPARSE;
options.linear_solver_type = ceres::SPARSE_NORMAL_CHOLESKY;
}
else if (ceres::IsSparseLinearAlgebraLibraryTypeAvailable(ceres::EIGEN_SPARSE))
{
options.sparse_linear_algebra_library_type = ceres::EIGEN_SPARSE;
options.linear_solver_type = ceres::SPARSE_NORMAL_CHOLESKY;
}
else
{
options.linear_solver_type = ceres::DENSE_NORMAL_CHOLESKY;
}
Solver::Summary summary;
Solve(options, &problem, &summary);
std::cout << summary.FullReport() << "\n";
if (summary.IsSolutionUsable())
{
// undo the re indexing
for (int i=0; i<num_nodes; ++i) {
const int j = reindexed_lookup[i];
X[3*j+0] = x[3*i+0];
X[3*j+1] = x[3*i+1];
X[3*j+2] = x[3*i+2];
}
}
return summary.IsSolutionUsable();
}
