gtsam/slam/LinearApproxFactor.h

107 lines
2.9 KiB
C++

/* ----------------------------------------------------------------------------
* 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
* -------------------------------------------------------------------------- */
/**
* @file LinearApproxFactor.h
* @brief A dummy factor that allows a linear factor to act as a nonlinear factor
* @author Alex Cunningham
*/
#pragma once
#include <vector>
#include <gtsam/nonlinear/NonlinearFactor.h>
namespace gtsam {
/**
* A dummy factor that takes a linearized factor and inserts it into
* a nonlinear graph. This version uses exactly one type of variable.
*/
template <class Values, class Key>
class LinearApproxFactor : public NonlinearFactor<Values> {
public:
/** type for the variable */
typedef typename Key::Value X;
/** base type */
typedef NonlinearFactor<Values> Base;
/** shared pointer for convenience */
typedef boost::shared_ptr<LinearApproxFactor<Values,Key> > shared_ptr;
/** typedefs for key vectors */
typedef std::vector<Key> KeyVector;
protected:
/** hold onto the factor itself */
// GaussianFactor::shared_ptr lin_factor_;
// store components of a linear factor that can be reordered
typedef std::map<Symbol, Matrix> SymbolMatrixMap;
SymbolMatrixMap matrices_;
Vector b_;
SharedDiagonal model_;
/** linearization points for error calculation */
Values lin_points_;
/** keep keys for the factor */
KeyVector nonlinearKeys_;
/**
* use this for derived classes with keys that don't copy easily
*/
LinearApproxFactor(size_t dim, const Values& lin_points)
: Base(noiseModel::Unit::Create(dim)), lin_points_(lin_points) {}
public:
/**
* use this constructor when starting with nonlinear keys
*
* Note that you need to have the ordering used to construct the factor
* initially in order to find the actual keys
*/
LinearApproxFactor(GaussianFactor::shared_ptr lin_factor,
const Ordering& ordering, const Values& lin_points);
virtual ~LinearApproxFactor() {}
/** Vector of errors, unwhitened ! */
virtual Vector unwhitenedError(const Values& c) const;
/**
* linearize to a GaussianFactor
* Reconstructs the linear factor from components to ensure that
* the ordering is correct
*/
virtual boost::shared_ptr<GaussianFactor> linearize(
const Values& c, const Ordering& ordering) const;
/**
* Create a symbolic factor using the given ordering to determine the
* variable indices.
*/
Factor::shared_ptr symbolic(const Ordering& ordering) const;
/** get access to nonlinear keys */
KeyVector nonlinearKeys() const { return nonlinearKeys_; }
/** override print function */
virtual void print(const std::string& s="") const;
/** access to b vector of gaussian */
Vector get_b() const { return b_; }
};
} // \namespace gtsam