gtsam/cpp/BetweenFactor.h

86 lines
2.4 KiB
C++

/**
* @file BetweenFactor.h
* @authors Frank Dellaert, Viorela Ila
**/
#pragma once
#include <ostream>
#include "NonlinearFactor.h"
#include "GaussianFactor.h"
#include "Lie.h"
#include "Matrix.h"
namespace gtsam {
/**
* A class for a measurement predicted by "between(config[key1],config[key2])"
* T is the Lie group type, Config where the T's are gotten from
*/
template<class Config, class Key, class T>
class BetweenFactor: public NonlinearFactor2<Config, Key, T, Key, T> {
private:
typedef NonlinearFactor2<Config, Key, T, Key, T> Base;
T measured_; /** The measurement */
Matrix square_root_inverse_covariance_; /** sqrt(inv(measurement_covariance)) */
public:
// shorthand for a smart pointer to a factor
typedef typename boost::shared_ptr<BetweenFactor> shared_ptr;
/** Constructor */
BetweenFactor(const Key& key1, const Key& key2, const T& measured,
const Matrix& measurement_covariance) :
Base(1, key1, key2), measured_(measured) {
square_root_inverse_covariance_ = inverse_square_root(
measurement_covariance);
}
/** implement functions needed for Testable */
/** print */
void print(const std::string& s) const {
Base::print(s);
measured_.print("measured ");
gtsam::print(square_root_inverse_covariance_, "MeasurementCovariance");
}
/** equals */
bool equals(const NonlinearFactor<Config>& expected, double tol) const {
const BetweenFactor<Config, Key, T> *e =
dynamic_cast<const BetweenFactor<Config, Key, T>*> (&expected);
return e != NULL && Base::equals(expected)
&& this->measured_.equals(e->measured_, tol);
}
/** implement functions needed to derive from Factor */
/** vector of errors */
Vector evaluateError(const T& p1, const T& p2, boost::optional<Matrix&> H1 =
boost::none, boost::optional<Matrix&> H2 = boost::none) const {
// h - z
T hx = between(p1, p2);
// TODO should be done by noise model
if (H1 || H2) {
between(p1,p2,H1,H2);
if (H1) *H1 = square_root_inverse_covariance_ * *H1;
if (H2) *H2 = square_root_inverse_covariance_ * *H2;
}
// manifold equivalent of h(x)-z -> log(z,h(x))
// TODO use noise model, error vector is not whitened yet
return square_root_inverse_covariance_ * logmap(measured_, hx);
}
/** return the measured */
inline const T measured() const {return measured_;}
/** number of variables attached to this factor */
inline std::size_t size() const { return 2;}
};
} /// namespace gtsam