98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
/**
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* @file BetweenFactor.h
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* @authors Frank Dellaert, Viorela Ila
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**/
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#pragma once
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#include <ostream>
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#include "NonlinearFactor.h"
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#include "GaussianFactor.h"
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#include "Lie.h"
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#include "Matrix.h"
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namespace gtsam {
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/**
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* A class for a measurement predicted by "between(config[key1],config[key2])"
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* T is the Lie group type, Config where the T's are gotten from
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*/
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template<class T, class Config>
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class BetweenFactor: public NonlinearFactor<Config> {
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private:
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T measured_; /** The measurement */
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std::string key1_, key2_; /** The keys of the two poses, order matters */
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std::list<std::string> keys_; /** The keys as a list */
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Matrix square_root_inverse_covariance_; /** sqrt(inv(measurement_covariance)) */
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public:
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// shorthand for a smart pointer to a factor
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typedef typename boost::shared_ptr<BetweenFactor> shared_ptr;
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/** Constructor */
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BetweenFactor(const std::string& key1, const std::string& key2,
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const T& measured, const Matrix& measurement_covariance) :
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key1_(key1), key2_(key2), measured_(measured) {
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square_root_inverse_covariance_ = inverse_square_root(
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measurement_covariance);
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keys_.push_back(key1);
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keys_.push_back(key2);
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}
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/** implement functions needed for Testable */
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/** print */
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void print(const std::string& name) const {
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std::cout << name << std::endl;
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std::cout << "Factor " << std::endl;
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std::cout << "key1 " << key1_ << std::endl;
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std::cout << "key2 " << key2_ << std::endl;
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measured_.print("measured ");
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gtsam::print(square_root_inverse_covariance_, "MeasurementCovariance");
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}
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/** equals */
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bool equals(const NonlinearFactor<Config>& expected, double tol) const {
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return key1_ == expected.key1_ && key2_ == expected.key2_
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&& measured_.equals(expected.measured_, tol);
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}
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/** implement functions needed to derive from Factor */
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/** vector of errors */
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Vector error_vector(const Config& x) const {
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//z-h
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const T& p1 = x.get(key1_), p2 = x.get(key2_);
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T hx = between(p1,p2);
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// manifold equivalent of z-h(x) -> log(h(x),z)
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return square_root_inverse_covariance_ * logmap(hx,measured_);
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}
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/** methods to retrieve both keys */
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inline const std::string& key1() const { return key1_;}
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inline const std::string& key2() const { return key2_;}
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/** keys as a list */
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inline std::list<std::string> keys() const { return keys_;}
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/** number of variables attached to this factor */
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inline std::size_t size() const { return 2;}
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/** linearize */
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boost::shared_ptr<GaussianFactor> linearize(const Config& x0) const {
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const T& p1 = x0.get(key1_), p2 = x0.get(key2_);
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Matrix A1 = Dbetween1(p1, p2);
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Matrix A2 = Dbetween2(p1, p2);
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Vector b = error_vector(x0); // already has sigmas in !
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boost::shared_ptr<GaussianFactor> linearized(new GaussianFactor(
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key1_, square_root_inverse_covariance_ * A1,
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key2_, square_root_inverse_covariance_ * A2, b, 1.0));
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return linearized;
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}
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};
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} /// namespace gtsam
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