gtsam/gtsam/sfm/ShonanFactor.cpp

142 lines
5.1 KiB
C++

/* ----------------------------------------------------------------------------
* GTSAM Copyright 2010-2019, 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
* -------------------------------------------------------------------------- */
/**
* @file FrobeniusFactor.cpp
* @date March 2019
* @author Frank Dellaert
* @brief Various factors that minimize some Frobenius norm
*/
#include <gtsam/sfm/ShonanFactor.h>
#include <gtsam/base/timing.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/slam/FrobeniusFactor.h>
#include <cmath>
#include <iostream>
#include <vector>
using namespace std;
namespace gtsam {
//******************************************************************************
template <size_t d>
ShonanFactor<d>::ShonanFactor(Key j1, Key j2, const Rot &R12, size_t p,
const SharedNoiseModel &model,
const std::shared_ptr<Matrix> &G)
: NoiseModelFactorN<SOn, SOn>(ConvertNoiseModel(model, p * d), j1, j2),
M_(R12.matrix()), // d*d in all cases
p_(p), // 4 for SO(4)
pp_(p * p), // 16 for SO(4)
G_(G) {
if (noiseModel()->dim() != d * p_)
throw std::invalid_argument(
"ShonanFactor: model with incorrect dimension.");
if (!G) {
G_ = std::make_shared<Matrix>();
*G_ = SOn::VectorizedGenerators(p); // expensive!
}
if (static_cast<size_t>(G_->rows()) != pp_ ||
static_cast<size_t>(G_->cols()) != SOn::Dimension(p))
throw std::invalid_argument("ShonanFactor: passed in generators "
"of incorrect dimension.");
}
//******************************************************************************
template <size_t d>
void ShonanFactor<d>::print(const std::string &s,
const KeyFormatter &keyFormatter) const {
std::cout << s << "ShonanFactor<" << p_ << ">(" << keyFormatter(key<1>()) << ","
<< keyFormatter(key<2>()) << ")\n";
traits<Matrix>::Print(M_, " M: ");
noiseModel_->print(" noise model: ");
}
//******************************************************************************
template <size_t d>
bool ShonanFactor<d>::equals(const NonlinearFactor &expected,
double tol) const {
auto e = dynamic_cast<const ShonanFactor *>(&expected);
return e != nullptr && NoiseModelFactorN<SOn, SOn>::equals(*e, tol) &&
p_ == e->p_ && M_ == e->M_;
}
//******************************************************************************
template <size_t d>
void ShonanFactor<d>::fillJacobians(const Matrix &M1, const Matrix &M2,
OptionalMatrixType H1,
OptionalMatrixType H2) const {
gttic(ShonanFactor_Jacobians);
const size_t dim = p_ * d; // Stiefel manifold dimension
if (H1) {
// If asked, calculate Jacobian H1 as as (M' \otimes M1) * G
// M' = dxd, M1 = pxp, G = (p*p)xDim(p), result should be dim x Dim(p)
// (M' \otimes M1) is dim*dim, but last pp-dim columns are zero
*H1 = Matrix::Zero(dim, G_->cols());
for (size_t j = 0; j < d; j++) {
auto MG_j = M1 * G_->middleRows(j * p_, p_); // p_ * Dim(p)
for (size_t i = 0; i < d; i++) {
H1->middleRows(i * p_, p_) -= M_(j, i) * MG_j;
}
}
}
if (H2) {
// If asked, calculate Jacobian H2 as as (I_d \otimes M2) * G
// I_d = dxd, M2 = pxp, G = (p*p)xDim(p), result should be dim x Dim(p)
// (I_d \otimes M2) is dim*dim, but again last pp-dim columns are zero
H2->resize(dim, G_->cols());
for (size_t i = 0; i < d; i++) {
H2->middleRows(i * p_, p_) = M2 * G_->middleRows(i * p_, p_);
}
}
}
//******************************************************************************
template <size_t d>
Vector ShonanFactor<d>::evaluateError(const SOn &Q1, const SOn &Q2,
OptionalMatrixType H1,
OptionalMatrixType H2) const {
gttic(ShonanFactor_evaluateError);
const Matrix &M1 = Q1.matrix();
const Matrix &M2 = Q2.matrix();
if (M1.rows() != static_cast<int>(p_) || M2.rows() != static_cast<int>(p_))
throw std::invalid_argument("Invalid dimension SOn values passed to "
"ShonanFactor<d>::evaluateError");
const size_t dim = p_ * d; // Stiefel manifold dimension
Vector fQ2(dim), hQ1(dim);
// Vectorize and extract only d leftmost columns, i.e. vec(M2*P)
fQ2 << Eigen::Map<const Matrix>(M2.data(), dim, 1);
// Vectorize M1*P*R12
const Matrix Q1PR12 = M1.leftCols<d>() * M_;
hQ1 << Eigen::Map<const Matrix>(Q1PR12.data(), dim, 1);
this->fillJacobians(M1, M2, H1, H2);
return fQ2 - hQ1;
}
/* ************************************************************************* */
// Explicit instantiation for d=2 and d=3
template class ShonanFactor<2>;
template class ShonanFactor<3>;
//******************************************************************************
} // namespace gtsam