gtsam/gtsam/nonlinear/NonlinearEquality.h

306 lines
9.4 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 NonlinearEquality.h
* @brief Factor to handle enforced equality between factors
* @author Alex Cunningham
*/
#pragma once
#include <limits>
#include <iostream>
#include <gtsam/nonlinear/NonlinearFactor.h>
#include <gtsam/base/Testable.h>
#include <gtsam/base/Manifold.h>
namespace gtsam {
/**
* Template default compare function that assumes a testable T
*/
template<class T>
bool compare(const T& a, const T& b) {
GTSAM_CONCEPT_TESTABLE_TYPE(T);
return a.equals(b);
}
/**
* An equality factor that forces either one variable to a constant,
* or a set of variables to be equal to each other.
*
* Depending on flag, throws an error at linearization if the constraints are not met.
*
* Switchable implementation:
* - ALLLOW_ERROR : if we allow that there can be nonzero error, does not throw, and uses gain
* - ONLY_EXACT : throws error at linearization if not at exact feasible point, and infinite error
*
* \nosubgrouping
*/
template<class VALUE>
class NonlinearEquality: public NoiseModelFactor1<VALUE> {
public:
typedef VALUE T;
private:
// feasible value
T feasible_;
// error handling flag
bool allow_error_;
// error gain in allow error case
double error_gain_;
// typedef to this class
typedef NonlinearEquality<VALUE> This;
// typedef to base class
typedef NoiseModelFactor1<VALUE> Base;
public:
/**
* Function that compares two values
*/
bool (*compare_)(const T& a, const T& b);
/** default constructor - only for serialization */
NonlinearEquality() {}
virtual ~NonlinearEquality() {}
/// @name Standard Constructors
/// @{
/**
* Constructor - forces exact evaluation
*/
NonlinearEquality(Key j, const T& feasible, bool (*_compare)(const T&, const T&) = compare<T>) :
Base(noiseModel::Constrained::All(feasible.dim()), j), feasible_(feasible),
allow_error_(false), error_gain_(0.0),
compare_(_compare) {
}
/**
* Constructor - allows inexact evaluation
*/
NonlinearEquality(Key j, const T& feasible, double error_gain, bool (*_compare)(const T&, const T&) = compare<T>) :
Base(noiseModel::Constrained::All(feasible.dim()), j), feasible_(feasible),
allow_error_(true), error_gain_(error_gain),
compare_(_compare) {
}
/// @}
/// @name Testable
/// @{
virtual void print(const std::string& s = "", const KeyFormatter& keyFormatter = DefaultKeyFormatter) const {
std::cout << s << "Constraint: on [" << keyFormatter(this->key()) << "]\n";
gtsam::print(feasible_,"Feasible Point:\n");
std::cout << "Variable Dimension: " << feasible_.dim() << std::endl;
}
/** Check if two factors are equal */
virtual bool equals(const NonlinearFactor& f, double tol = 1e-9) const {
const This* e = dynamic_cast<const This*>(&f);
return e && Base::equals(f) && feasible_.equals(e->feasible_, tol) &&
fabs(error_gain_ - e->error_gain_) < tol;
}
/// @}
/// @name Standard Interface
/// @{
/** actual error function calculation */
virtual double error(const Values& c) const {
const T& xj = c.at<T>(this->key());
Vector e = this->unwhitenedError(c);
if (allow_error_ || !compare_(xj, feasible_)) {
return error_gain_ * dot(e,e);
} else {
return 0.0;
}
}
/** error function */
Vector evaluateError(const T& xj, boost::optional<Matrix&> H = boost::none) const {
size_t nj = feasible_.dim();
if (allow_error_) {
if (H) *H = eye(nj); // FIXME: this is not the right linearization for nonlinear compare
return xj.localCoordinates(feasible_);
} else if (compare_(feasible_,xj)) {
if (H) *H = eye(nj);
return zero(nj); // set error to zero if equal
} else {
if (H) throw std::invalid_argument(
"Linearization point not feasible for " + DefaultKeyFormatter(this->key()) + "!");
return repeat(nj, std::numeric_limits<double>::infinity()); // set error to infinity if not equal
}
}
// Linearize is over-written, because base linearization tries to whiten
virtual GaussianFactor::shared_ptr linearize(const Values& x) const {
const T& xj = x.at<T>(this->key());
Matrix A;
Vector b = evaluateError(xj, A);
SharedDiagonal model = noiseModel::Constrained::All(b.size());
return GaussianFactor::shared_ptr(new JacobianFactor(this->key(), A, b, model));
}
/// @return a deep copy of this factor
virtual gtsam::NonlinearFactor::shared_ptr clone() const {
return boost::static_pointer_cast<gtsam::NonlinearFactor>(
gtsam::NonlinearFactor::shared_ptr(new This(*this))); }
/// @}
private:
/** Serialization function */
friend class boost::serialization::access;
template<class ARCHIVE>
void serialize(ARCHIVE & ar, const unsigned int version) {
ar & boost::serialization::make_nvp("NoiseModelFactor1",
boost::serialization::base_object<Base>(*this));
ar & BOOST_SERIALIZATION_NVP(feasible_);
ar & BOOST_SERIALIZATION_NVP(allow_error_);
ar & BOOST_SERIALIZATION_NVP(error_gain_);
}
}; // \class NonlinearEquality
/* ************************************************************************* */
/**
* Simple unary equality constraint - fixes a value for a variable
*/
template<class VALUE>
class NonlinearEquality1 : public NoiseModelFactor1<VALUE> {
public:
typedef VALUE X;
protected:
typedef NoiseModelFactor1<VALUE> Base;
typedef NonlinearEquality1<VALUE> This;
/** default constructor to allow for serialization */
NonlinearEquality1() {}
X value_; /// fixed value for variable
GTSAM_CONCEPT_MANIFOLD_TYPE(X);
GTSAM_CONCEPT_TESTABLE_TYPE(X);
public:
typedef boost::shared_ptr<NonlinearEquality1<VALUE> > shared_ptr;
///TODO: comment
NonlinearEquality1(const X& value, Key key1, double mu = 1000.0)
: Base(noiseModel::Constrained::All(value.dim(), fabs(mu)), key1), value_(value) {}
virtual ~NonlinearEquality1() {}
/// @return a deep copy of this factor
virtual gtsam::NonlinearFactor::shared_ptr clone() const {
return boost::static_pointer_cast<gtsam::NonlinearFactor>(
gtsam::NonlinearFactor::shared_ptr(new This(*this))); }
/** g(x) with optional derivative */
Vector evaluateError(const X& x1, boost::optional<Matrix&> H = boost::none) const {
if (H) (*H) = eye(x1.dim());
// manifold equivalent of h(x)-z -> log(z,h(x))
return value_.localCoordinates(x1);
}
/** Print */
virtual void print(const std::string& s = "", const KeyFormatter& keyFormatter = DefaultKeyFormatter) const {
std::cout << s << ": NonlinearEquality1("
<< keyFormatter(this->key()) << "),"<< "\n";
this->noiseModel_->print();
value_.print("Value");
}
private:
/** Serialization function */
friend class boost::serialization::access;
template<class ARCHIVE>
void serialize(ARCHIVE & ar, const unsigned int version) {
ar & boost::serialization::make_nvp("NoiseModelFactor1",
boost::serialization::base_object<Base>(*this));
ar & BOOST_SERIALIZATION_NVP(value_);
}
}; // \NonlinearEquality1
/* ************************************************************************* */
/**
* Simple binary equality constraint - this constraint forces two factors to
* be the same.
*/
template<class VALUE>
class NonlinearEquality2 : public NoiseModelFactor2<VALUE, VALUE> {
public:
typedef VALUE X;
protected:
typedef NoiseModelFactor2<VALUE, VALUE> Base;
typedef NonlinearEquality2<VALUE> This;
GTSAM_CONCEPT_MANIFOLD_TYPE(X);
/** default constructor to allow for serialization */
NonlinearEquality2() {}
public:
typedef boost::shared_ptr<NonlinearEquality2<VALUE> > shared_ptr;
///TODO: comment
NonlinearEquality2(Key key1, Key key2, double mu = 1000.0)
: Base(noiseModel::Constrained::All(X::Dim(), fabs(mu)), key1, key2) {}
virtual ~NonlinearEquality2() {}
/// @return a deep copy of this factor
virtual gtsam::NonlinearFactor::shared_ptr clone() const {
return boost::static_pointer_cast<gtsam::NonlinearFactor>(
gtsam::NonlinearFactor::shared_ptr(new This(*this))); }
/** g(x) with optional derivative2 */
Vector evaluateError(const X& x1, const X& x2,
boost::optional<Matrix&> H1 = boost::none,
boost::optional<Matrix&> H2 = boost::none) const {
const size_t p = X::Dim();
if (H1) *H1 = -eye(p);
if (H2) *H2 = eye(p);
return x1.localCoordinates(x2);
}
private:
/** Serialization function */
friend class boost::serialization::access;
template<class ARCHIVE>
void serialize(ARCHIVE & ar, const unsigned int version) {
ar & boost::serialization::make_nvp("NoiseModelFactor2",
boost::serialization::base_object<Base>(*this));
}
}; // \NonlinearEquality2
} // namespace gtsam