758 lines
27 KiB
C++
758 lines
27 KiB
C++
// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2015 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: sameeragarwal@google.com (Sameer Agarwal)
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#include "ceres/covariance_impl.h"
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#ifdef CERES_USE_OPENMP
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#include <omp.h>
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#endif
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#include <algorithm>
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#include <cstdlib>
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#include <utility>
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#include <vector>
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#include "Eigen/SparseCore"
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#include "Eigen/SparseQR"
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#include "Eigen/SVD"
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#include "ceres/compressed_col_sparse_matrix_utils.h"
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#include "ceres/compressed_row_sparse_matrix.h"
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#include "ceres/covariance.h"
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#include "ceres/crs_matrix.h"
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#include "ceres/internal/eigen.h"
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#include "ceres/map_util.h"
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#include "ceres/parameter_block.h"
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#include "ceres/problem_impl.h"
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#include "ceres/suitesparse.h"
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#include "ceres/wall_time.h"
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#include "glog/logging.h"
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namespace ceres {
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namespace internal {
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using std::make_pair;
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using std::map;
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using std::pair;
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using std::swap;
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using std::vector;
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typedef vector<pair<const double*, const double*> > CovarianceBlocks;
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CovarianceImpl::CovarianceImpl(const Covariance::Options& options)
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: options_(options),
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is_computed_(false),
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is_valid_(false) {
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#ifndef CERES_USE_OPENMP
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if (options_.num_threads > 1) {
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LOG(WARNING)
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<< "OpenMP support is not compiled into this binary; "
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<< "only options.num_threads = 1 is supported. Switching "
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<< "to single threaded mode.";
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options_.num_threads = 1;
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}
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#endif
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evaluate_options_.num_threads = options_.num_threads;
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evaluate_options_.apply_loss_function = options_.apply_loss_function;
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}
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CovarianceImpl::~CovarianceImpl() {
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}
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bool CovarianceImpl::Compute(const CovarianceBlocks& covariance_blocks,
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ProblemImpl* problem) {
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problem_ = problem;
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parameter_block_to_row_index_.clear();
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covariance_matrix_.reset(NULL);
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is_valid_ = (ComputeCovarianceSparsity(covariance_blocks, problem) &&
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ComputeCovarianceValues());
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is_computed_ = true;
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return is_valid_;
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}
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bool CovarianceImpl::GetCovarianceBlockInTangentOrAmbientSpace(
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const double* original_parameter_block1,
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const double* original_parameter_block2,
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bool lift_covariance_to_ambient_space,
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double* covariance_block) const {
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CHECK(is_computed_)
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<< "Covariance::GetCovarianceBlock called before Covariance::Compute";
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CHECK(is_valid_)
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<< "Covariance::GetCovarianceBlock called when Covariance::Compute "
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<< "returned false.";
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// If either of the two parameter blocks is constant, then the
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// covariance block is also zero.
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if (constant_parameter_blocks_.count(original_parameter_block1) > 0 ||
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constant_parameter_blocks_.count(original_parameter_block2) > 0) {
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const ProblemImpl::ParameterMap& parameter_map = problem_->parameter_map();
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ParameterBlock* block1 =
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FindOrDie(parameter_map,
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const_cast<double*>(original_parameter_block1));
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ParameterBlock* block2 =
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FindOrDie(parameter_map,
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const_cast<double*>(original_parameter_block2));
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const int block1_size = block1->Size();
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const int block2_size = block2->Size();
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MatrixRef(covariance_block, block1_size, block2_size).setZero();
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return true;
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}
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const double* parameter_block1 = original_parameter_block1;
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const double* parameter_block2 = original_parameter_block2;
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const bool transpose = parameter_block1 > parameter_block2;
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if (transpose) {
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swap(parameter_block1, parameter_block2);
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}
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// Find where in the covariance matrix the block is located.
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const int row_begin =
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FindOrDie(parameter_block_to_row_index_, parameter_block1);
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const int col_begin =
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FindOrDie(parameter_block_to_row_index_, parameter_block2);
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const int* rows = covariance_matrix_->rows();
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const int* cols = covariance_matrix_->cols();
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const int row_size = rows[row_begin + 1] - rows[row_begin];
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const int* cols_begin = cols + rows[row_begin];
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// The only part that requires work is walking the compressed column
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// vector to determine where the set of columns correspnding to the
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// covariance block begin.
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int offset = 0;
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while (cols_begin[offset] != col_begin && offset < row_size) {
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++offset;
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}
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if (offset == row_size) {
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LOG(ERROR) << "Unable to find covariance block for "
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<< original_parameter_block1 << " "
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<< original_parameter_block2;
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return false;
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}
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const ProblemImpl::ParameterMap& parameter_map = problem_->parameter_map();
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ParameterBlock* block1 =
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FindOrDie(parameter_map, const_cast<double*>(parameter_block1));
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ParameterBlock* block2 =
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FindOrDie(parameter_map, const_cast<double*>(parameter_block2));
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const LocalParameterization* local_param1 = block1->local_parameterization();
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const LocalParameterization* local_param2 = block2->local_parameterization();
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const int block1_size = block1->Size();
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const int block1_local_size = block1->LocalSize();
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const int block2_size = block2->Size();
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const int block2_local_size = block2->LocalSize();
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ConstMatrixRef cov(covariance_matrix_->values() + rows[row_begin],
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block1_size,
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row_size);
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// Fast path when there are no local parameterizations or if the
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// user does not want it lifted to the ambient space.
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if ((local_param1 == NULL && local_param2 == NULL) ||
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!lift_covariance_to_ambient_space) {
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if (transpose) {
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MatrixRef(covariance_block, block2_local_size, block1_local_size) =
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cov.block(0, offset, block1_local_size,
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block2_local_size).transpose();
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} else {
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MatrixRef(covariance_block, block1_local_size, block2_local_size) =
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cov.block(0, offset, block1_local_size, block2_local_size);
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}
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return true;
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}
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// If local parameterizations are used then the covariance that has
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// been computed is in the tangent space and it needs to be lifted
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// back to the ambient space.
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//
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// This is given by the formula
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//
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// C'_12 = J_1 C_12 J_2'
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//
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// Where C_12 is the local tangent space covariance for parameter
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// blocks 1 and 2. J_1 and J_2 are respectively the local to global
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// jacobians for parameter blocks 1 and 2.
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//
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// See Result 5.11 on page 142 of Hartley & Zisserman (2nd Edition)
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// for a proof.
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//
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// TODO(sameeragarwal): Add caching of local parameterization, so
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// that they are computed just once per parameter block.
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Matrix block1_jacobian(block1_size, block1_local_size);
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if (local_param1 == NULL) {
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block1_jacobian.setIdentity();
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} else {
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local_param1->ComputeJacobian(parameter_block1, block1_jacobian.data());
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}
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Matrix block2_jacobian(block2_size, block2_local_size);
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// Fast path if the user is requesting a diagonal block.
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if (parameter_block1 == parameter_block2) {
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block2_jacobian = block1_jacobian;
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} else {
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if (local_param2 == NULL) {
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block2_jacobian.setIdentity();
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} else {
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local_param2->ComputeJacobian(parameter_block2, block2_jacobian.data());
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}
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}
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if (transpose) {
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MatrixRef(covariance_block, block2_size, block1_size) =
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block2_jacobian *
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cov.block(0, offset, block1_local_size, block2_local_size).transpose() *
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block1_jacobian.transpose();
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} else {
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MatrixRef(covariance_block, block1_size, block2_size) =
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block1_jacobian *
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cov.block(0, offset, block1_local_size, block2_local_size) *
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block2_jacobian.transpose();
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}
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return true;
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}
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// Determine the sparsity pattern of the covariance matrix based on
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// the block pairs requested by the user.
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bool CovarianceImpl::ComputeCovarianceSparsity(
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const CovarianceBlocks& original_covariance_blocks,
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ProblemImpl* problem) {
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EventLogger event_logger("CovarianceImpl::ComputeCovarianceSparsity");
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// Determine an ordering for the parameter block, by sorting the
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// parameter blocks by their pointers.
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vector<double*> all_parameter_blocks;
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problem->GetParameterBlocks(&all_parameter_blocks);
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const ProblemImpl::ParameterMap& parameter_map = problem->parameter_map();
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constant_parameter_blocks_.clear();
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vector<double*>& active_parameter_blocks =
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evaluate_options_.parameter_blocks;
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active_parameter_blocks.clear();
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for (int i = 0; i < all_parameter_blocks.size(); ++i) {
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double* parameter_block = all_parameter_blocks[i];
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ParameterBlock* block = FindOrDie(parameter_map, parameter_block);
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if (block->IsConstant()) {
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constant_parameter_blocks_.insert(parameter_block);
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} else {
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active_parameter_blocks.push_back(parameter_block);
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}
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}
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std::sort(active_parameter_blocks.begin(), active_parameter_blocks.end());
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// Compute the number of rows. Map each parameter block to the
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// first row corresponding to it in the covariance matrix using the
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// ordering of parameter blocks just constructed.
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int num_rows = 0;
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parameter_block_to_row_index_.clear();
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for (int i = 0; i < active_parameter_blocks.size(); ++i) {
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double* parameter_block = active_parameter_blocks[i];
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const int parameter_block_size =
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problem->ParameterBlockLocalSize(parameter_block);
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parameter_block_to_row_index_[parameter_block] = num_rows;
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num_rows += parameter_block_size;
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}
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// Compute the number of non-zeros in the covariance matrix. Along
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// the way flip any covariance blocks which are in the lower
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// triangular part of the matrix.
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int num_nonzeros = 0;
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CovarianceBlocks covariance_blocks;
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for (int i = 0; i < original_covariance_blocks.size(); ++i) {
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const pair<const double*, const double*>& block_pair =
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original_covariance_blocks[i];
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if (constant_parameter_blocks_.count(block_pair.first) > 0 ||
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constant_parameter_blocks_.count(block_pair.second) > 0) {
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continue;
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}
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int index1 = FindOrDie(parameter_block_to_row_index_, block_pair.first);
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int index2 = FindOrDie(parameter_block_to_row_index_, block_pair.second);
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const int size1 = problem->ParameterBlockLocalSize(block_pair.first);
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const int size2 = problem->ParameterBlockLocalSize(block_pair.second);
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num_nonzeros += size1 * size2;
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// Make sure we are constructing a block upper triangular matrix.
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if (index1 > index2) {
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covariance_blocks.push_back(make_pair(block_pair.second,
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block_pair.first));
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} else {
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covariance_blocks.push_back(block_pair);
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}
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}
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if (covariance_blocks.size() == 0) {
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VLOG(2) << "No non-zero covariance blocks found";
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covariance_matrix_.reset(NULL);
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return true;
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}
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// Sort the block pairs. As a consequence we get the covariance
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// blocks as they will occur in the CompressedRowSparseMatrix that
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// will store the covariance.
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sort(covariance_blocks.begin(), covariance_blocks.end());
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// Fill the sparsity pattern of the covariance matrix.
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covariance_matrix_.reset(
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new CompressedRowSparseMatrix(num_rows, num_rows, num_nonzeros));
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int* rows = covariance_matrix_->mutable_rows();
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int* cols = covariance_matrix_->mutable_cols();
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// Iterate over parameter blocks and in turn over the rows of the
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// covariance matrix. For each parameter block, look in the upper
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// triangular part of the covariance matrix to see if there are any
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// blocks requested by the user. If this is the case then fill out a
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// set of compressed rows corresponding to this parameter block.
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//
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// The key thing that makes this loop work is the fact that the
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// row/columns of the covariance matrix are ordered by the pointer
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// values of the parameter blocks. Thus iterating over the keys of
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// parameter_block_to_row_index_ corresponds to iterating over the
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// rows of the covariance matrix in order.
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int i = 0; // index into covariance_blocks.
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int cursor = 0; // index into the covariance matrix.
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for (map<const double*, int>::const_iterator it =
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parameter_block_to_row_index_.begin();
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it != parameter_block_to_row_index_.end();
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++it) {
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const double* row_block = it->first;
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const int row_block_size = problem->ParameterBlockLocalSize(row_block);
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int row_begin = it->second;
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// Iterate over the covariance blocks contained in this row block
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// and count the number of columns in this row block.
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int num_col_blocks = 0;
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int num_columns = 0;
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for (int j = i; j < covariance_blocks.size(); ++j, ++num_col_blocks) {
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const pair<const double*, const double*>& block_pair =
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covariance_blocks[j];
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if (block_pair.first != row_block) {
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break;
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}
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num_columns += problem->ParameterBlockLocalSize(block_pair.second);
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}
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// Fill out all the compressed rows for this parameter block.
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for (int r = 0; r < row_block_size; ++r) {
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rows[row_begin + r] = cursor;
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for (int c = 0; c < num_col_blocks; ++c) {
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const double* col_block = covariance_blocks[i + c].second;
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const int col_block_size = problem->ParameterBlockLocalSize(col_block);
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int col_begin = FindOrDie(parameter_block_to_row_index_, col_block);
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for (int k = 0; k < col_block_size; ++k) {
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cols[cursor++] = col_begin++;
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}
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}
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}
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i+= num_col_blocks;
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}
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rows[num_rows] = cursor;
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return true;
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}
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bool CovarianceImpl::ComputeCovarianceValues() {
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switch (options_.algorithm_type) {
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case DENSE_SVD:
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return ComputeCovarianceValuesUsingDenseSVD();
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#ifndef CERES_NO_SUITESPARSE
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case SUITE_SPARSE_QR:
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return ComputeCovarianceValuesUsingSuiteSparseQR();
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#else
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LOG(ERROR) << "SuiteSparse is required to use the "
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<< "SUITE_SPARSE_QR algorithm.";
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return false;
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#endif
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case EIGEN_SPARSE_QR:
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return ComputeCovarianceValuesUsingEigenSparseQR();
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default:
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LOG(ERROR) << "Unsupported covariance estimation algorithm type: "
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<< CovarianceAlgorithmTypeToString(options_.algorithm_type);
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return false;
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}
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return false;
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}
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bool CovarianceImpl::ComputeCovarianceValuesUsingSuiteSparseQR() {
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EventLogger event_logger(
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"CovarianceImpl::ComputeCovarianceValuesUsingSparseQR");
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#ifndef CERES_NO_SUITESPARSE
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if (covariance_matrix_.get() == NULL) {
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// Nothing to do, all zeros covariance matrix.
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return true;
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}
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CRSMatrix jacobian;
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problem_->Evaluate(evaluate_options_, NULL, NULL, NULL, &jacobian);
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event_logger.AddEvent("Evaluate");
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// Construct a compressed column form of the Jacobian.
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const int num_rows = jacobian.num_rows;
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const int num_cols = jacobian.num_cols;
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const int num_nonzeros = jacobian.values.size();
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vector<SuiteSparse_long> transpose_rows(num_cols + 1, 0);
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vector<SuiteSparse_long> transpose_cols(num_nonzeros, 0);
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vector<double> transpose_values(num_nonzeros, 0);
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for (int idx = 0; idx < num_nonzeros; ++idx) {
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transpose_rows[jacobian.cols[idx] + 1] += 1;
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}
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for (int i = 1; i < transpose_rows.size(); ++i) {
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transpose_rows[i] += transpose_rows[i - 1];
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}
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for (int r = 0; r < num_rows; ++r) {
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for (int idx = jacobian.rows[r]; idx < jacobian.rows[r + 1]; ++idx) {
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const int c = jacobian.cols[idx];
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const int transpose_idx = transpose_rows[c];
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transpose_cols[transpose_idx] = r;
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transpose_values[transpose_idx] = jacobian.values[idx];
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++transpose_rows[c];
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}
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}
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for (int i = transpose_rows.size() - 1; i > 0 ; --i) {
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transpose_rows[i] = transpose_rows[i - 1];
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}
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transpose_rows[0] = 0;
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cholmod_sparse cholmod_jacobian;
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cholmod_jacobian.nrow = num_rows;
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cholmod_jacobian.ncol = num_cols;
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cholmod_jacobian.nzmax = num_nonzeros;
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cholmod_jacobian.nz = NULL;
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cholmod_jacobian.p = reinterpret_cast<void*>(&transpose_rows[0]);
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cholmod_jacobian.i = reinterpret_cast<void*>(&transpose_cols[0]);
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cholmod_jacobian.x = reinterpret_cast<void*>(&transpose_values[0]);
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cholmod_jacobian.z = NULL;
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cholmod_jacobian.stype = 0; // Matrix is not symmetric.
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cholmod_jacobian.itype = CHOLMOD_LONG;
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cholmod_jacobian.xtype = CHOLMOD_REAL;
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cholmod_jacobian.dtype = CHOLMOD_DOUBLE;
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cholmod_jacobian.sorted = 1;
|
|
cholmod_jacobian.packed = 1;
|
|
|
|
cholmod_common cc;
|
|
cholmod_l_start(&cc);
|
|
|
|
cholmod_sparse* R = NULL;
|
|
SuiteSparse_long* permutation = NULL;
|
|
|
|
// Compute a Q-less QR factorization of the Jacobian. Since we are
|
|
// only interested in inverting J'J = R'R, we do not need Q. This
|
|
// saves memory and gives us R as a permuted compressed column
|
|
// sparse matrix.
|
|
//
|
|
// TODO(sameeragarwal): Currently the symbolic factorization and the
|
|
// numeric factorization is done at the same time, and this does not
|
|
// explicitly account for the block column and row structure in the
|
|
// matrix. When using AMD, we have observed in the past that
|
|
// computing the ordering with the block matrix is significantly
|
|
// more efficient, both in runtime as well as the quality of
|
|
// ordering computed. So, it maybe worth doing that analysis
|
|
// separately.
|
|
const SuiteSparse_long rank =
|
|
SuiteSparseQR<double>(SPQR_ORDERING_BESTAMD,
|
|
SPQR_DEFAULT_TOL,
|
|
cholmod_jacobian.ncol,
|
|
&cholmod_jacobian,
|
|
&R,
|
|
&permutation,
|
|
&cc);
|
|
event_logger.AddEvent("Numeric Factorization");
|
|
CHECK_NOTNULL(permutation);
|
|
CHECK_NOTNULL(R);
|
|
|
|
if (rank < cholmod_jacobian.ncol) {
|
|
LOG(ERROR) << "Jacobian matrix is rank deficient. "
|
|
<< "Number of columns: " << cholmod_jacobian.ncol
|
|
<< " rank: " << rank;
|
|
free(permutation);
|
|
cholmod_l_free_sparse(&R, &cc);
|
|
cholmod_l_finish(&cc);
|
|
return false;
|
|
}
|
|
|
|
vector<int> inverse_permutation(num_cols);
|
|
for (SuiteSparse_long i = 0; i < num_cols; ++i) {
|
|
inverse_permutation[permutation[i]] = i;
|
|
}
|
|
|
|
const int* rows = covariance_matrix_->rows();
|
|
const int* cols = covariance_matrix_->cols();
|
|
double* values = covariance_matrix_->mutable_values();
|
|
|
|
// The following loop exploits the fact that the i^th column of A^{-1}
|
|
// is given by the solution to the linear system
|
|
//
|
|
// A x = e_i
|
|
//
|
|
// where e_i is a vector with e(i) = 1 and all other entries zero.
|
|
//
|
|
// Since the covariance matrix is symmetric, the i^th row and column
|
|
// are equal.
|
|
const int num_threads = options_.num_threads;
|
|
scoped_array<double> workspace(new double[num_threads * num_cols]);
|
|
|
|
#pragma omp parallel for num_threads(num_threads) schedule(dynamic)
|
|
for (int r = 0; r < num_cols; ++r) {
|
|
const int row_begin = rows[r];
|
|
const int row_end = rows[r + 1];
|
|
if (row_end == row_begin) {
|
|
continue;
|
|
}
|
|
|
|
# ifdef CERES_USE_OPENMP
|
|
int thread_id = omp_get_thread_num();
|
|
# else
|
|
int thread_id = 0;
|
|
# endif
|
|
|
|
double* solution = workspace.get() + thread_id * num_cols;
|
|
SolveRTRWithSparseRHS<SuiteSparse_long>(
|
|
num_cols,
|
|
static_cast<SuiteSparse_long*>(R->i),
|
|
static_cast<SuiteSparse_long*>(R->p),
|
|
static_cast<double*>(R->x),
|
|
inverse_permutation[r],
|
|
solution);
|
|
for (int idx = row_begin; idx < row_end; ++idx) {
|
|
const int c = cols[idx];
|
|
values[idx] = solution[inverse_permutation[c]];
|
|
}
|
|
}
|
|
|
|
free(permutation);
|
|
cholmod_l_free_sparse(&R, &cc);
|
|
cholmod_l_finish(&cc);
|
|
event_logger.AddEvent("Inversion");
|
|
return true;
|
|
|
|
#else // CERES_NO_SUITESPARSE
|
|
|
|
return false;
|
|
|
|
#endif // CERES_NO_SUITESPARSE
|
|
}
|
|
|
|
bool CovarianceImpl::ComputeCovarianceValuesUsingDenseSVD() {
|
|
EventLogger event_logger(
|
|
"CovarianceImpl::ComputeCovarianceValuesUsingDenseSVD");
|
|
if (covariance_matrix_.get() == NULL) {
|
|
// Nothing to do, all zeros covariance matrix.
|
|
return true;
|
|
}
|
|
|
|
CRSMatrix jacobian;
|
|
problem_->Evaluate(evaluate_options_, NULL, NULL, NULL, &jacobian);
|
|
event_logger.AddEvent("Evaluate");
|
|
|
|
Matrix dense_jacobian(jacobian.num_rows, jacobian.num_cols);
|
|
dense_jacobian.setZero();
|
|
for (int r = 0; r < jacobian.num_rows; ++r) {
|
|
for (int idx = jacobian.rows[r]; idx < jacobian.rows[r + 1]; ++idx) {
|
|
const int c = jacobian.cols[idx];
|
|
dense_jacobian(r, c) = jacobian.values[idx];
|
|
}
|
|
}
|
|
event_logger.AddEvent("ConvertToDenseMatrix");
|
|
|
|
Eigen::JacobiSVD<Matrix> svd(dense_jacobian,
|
|
Eigen::ComputeThinU | Eigen::ComputeThinV);
|
|
|
|
event_logger.AddEvent("SingularValueDecomposition");
|
|
|
|
const Vector singular_values = svd.singularValues();
|
|
const int num_singular_values = singular_values.rows();
|
|
Vector inverse_squared_singular_values(num_singular_values);
|
|
inverse_squared_singular_values.setZero();
|
|
|
|
const double max_singular_value = singular_values[0];
|
|
const double min_singular_value_ratio =
|
|
sqrt(options_.min_reciprocal_condition_number);
|
|
|
|
const bool automatic_truncation = (options_.null_space_rank < 0);
|
|
const int max_rank = std::min(num_singular_values,
|
|
num_singular_values - options_.null_space_rank);
|
|
|
|
// Compute the squared inverse of the singular values. Truncate the
|
|
// computation based on min_singular_value_ratio and
|
|
// null_space_rank. When either of these two quantities are active,
|
|
// the resulting covariance matrix is a Moore-Penrose inverse
|
|
// instead of a regular inverse.
|
|
for (int i = 0; i < max_rank; ++i) {
|
|
const double singular_value_ratio = singular_values[i] / max_singular_value;
|
|
if (singular_value_ratio < min_singular_value_ratio) {
|
|
// Since the singular values are in decreasing order, if
|
|
// automatic truncation is enabled, then from this point on
|
|
// all values will fail the ratio test and there is nothing to
|
|
// do in this loop.
|
|
if (automatic_truncation) {
|
|
break;
|
|
} else {
|
|
LOG(ERROR) << "Cholesky factorization of J'J is not reliable. "
|
|
<< "Reciprocal condition number: "
|
|
<< singular_value_ratio * singular_value_ratio << " "
|
|
<< "min_reciprocal_condition_number: "
|
|
<< options_.min_reciprocal_condition_number;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
inverse_squared_singular_values[i] =
|
|
1.0 / (singular_values[i] * singular_values[i]);
|
|
}
|
|
|
|
Matrix dense_covariance =
|
|
svd.matrixV() *
|
|
inverse_squared_singular_values.asDiagonal() *
|
|
svd.matrixV().transpose();
|
|
event_logger.AddEvent("PseudoInverse");
|
|
|
|
const int num_rows = covariance_matrix_->num_rows();
|
|
const int* rows = covariance_matrix_->rows();
|
|
const int* cols = covariance_matrix_->cols();
|
|
double* values = covariance_matrix_->mutable_values();
|
|
|
|
for (int r = 0; r < num_rows; ++r) {
|
|
for (int idx = rows[r]; idx < rows[r + 1]; ++idx) {
|
|
const int c = cols[idx];
|
|
values[idx] = dense_covariance(r, c);
|
|
}
|
|
}
|
|
event_logger.AddEvent("CopyToCovarianceMatrix");
|
|
return true;
|
|
}
|
|
|
|
bool CovarianceImpl::ComputeCovarianceValuesUsingEigenSparseQR() {
|
|
EventLogger event_logger(
|
|
"CovarianceImpl::ComputeCovarianceValuesUsingEigenSparseQR");
|
|
if (covariance_matrix_.get() == NULL) {
|
|
// Nothing to do, all zeros covariance matrix.
|
|
return true;
|
|
}
|
|
|
|
CRSMatrix jacobian;
|
|
problem_->Evaluate(evaluate_options_, NULL, NULL, NULL, &jacobian);
|
|
event_logger.AddEvent("Evaluate");
|
|
|
|
typedef Eigen::SparseMatrix<double, Eigen::ColMajor> EigenSparseMatrix;
|
|
|
|
// Convert the matrix to column major order as required by SparseQR.
|
|
EigenSparseMatrix sparse_jacobian =
|
|
Eigen::MappedSparseMatrix<double, Eigen::RowMajor>(
|
|
jacobian.num_rows, jacobian.num_cols,
|
|
static_cast<int>(jacobian.values.size()),
|
|
jacobian.rows.data(), jacobian.cols.data(), jacobian.values.data());
|
|
event_logger.AddEvent("ConvertToSparseMatrix");
|
|
|
|
Eigen::SparseQR<EigenSparseMatrix, Eigen::COLAMDOrdering<int> >
|
|
qr_solver(sparse_jacobian);
|
|
event_logger.AddEvent("QRDecomposition");
|
|
|
|
if (qr_solver.info() != Eigen::Success) {
|
|
LOG(ERROR) << "Eigen::SparseQR decomposition failed.";
|
|
return false;
|
|
}
|
|
|
|
if (qr_solver.rank() < jacobian.num_cols) {
|
|
LOG(ERROR) << "Jacobian matrix is rank deficient. "
|
|
<< "Number of columns: " << jacobian.num_cols
|
|
<< " rank: " << qr_solver.rank();
|
|
return false;
|
|
}
|
|
|
|
const int* rows = covariance_matrix_->rows();
|
|
const int* cols = covariance_matrix_->cols();
|
|
double* values = covariance_matrix_->mutable_values();
|
|
|
|
// Compute the inverse column permutation used by QR factorization.
|
|
Eigen::PermutationMatrix<Eigen::Dynamic, Eigen::Dynamic> inverse_permutation =
|
|
qr_solver.colsPermutation().inverse();
|
|
|
|
// The following loop exploits the fact that the i^th column of A^{-1}
|
|
// is given by the solution to the linear system
|
|
//
|
|
// A x = e_i
|
|
//
|
|
// where e_i is a vector with e(i) = 1 and all other entries zero.
|
|
//
|
|
// Since the covariance matrix is symmetric, the i^th row and column
|
|
// are equal.
|
|
const int num_cols = jacobian.num_cols;
|
|
const int num_threads = options_.num_threads;
|
|
scoped_array<double> workspace(new double[num_threads * num_cols]);
|
|
|
|
#pragma omp parallel for num_threads(num_threads) schedule(dynamic)
|
|
for (int r = 0; r < num_cols; ++r) {
|
|
const int row_begin = rows[r];
|
|
const int row_end = rows[r + 1];
|
|
if (row_end == row_begin) {
|
|
continue;
|
|
}
|
|
|
|
# ifdef CERES_USE_OPENMP
|
|
int thread_id = omp_get_thread_num();
|
|
# else
|
|
int thread_id = 0;
|
|
# endif
|
|
|
|
double* solution = workspace.get() + thread_id * num_cols;
|
|
SolveRTRWithSparseRHS<int>(
|
|
num_cols,
|
|
qr_solver.matrixR().innerIndexPtr(),
|
|
qr_solver.matrixR().outerIndexPtr(),
|
|
&qr_solver.matrixR().data().value(0),
|
|
inverse_permutation.indices().coeff(r),
|
|
solution);
|
|
|
|
// Assign the values of the computed covariance using the
|
|
// inverse permutation used in the QR factorization.
|
|
for (int idx = row_begin; idx < row_end; ++idx) {
|
|
const int c = cols[idx];
|
|
values[idx] = solution[inverse_permutation.indices().coeff(c)];
|
|
}
|
|
}
|
|
|
|
event_logger.AddEvent("Inverse");
|
|
|
|
return true;
|
|
}
|
|
|
|
} // namespace internal
|
|
} // namespace ceres
|