gtsam/gtsam/nonlinear/Symbol.h

143 lines
3.8 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 Symbol.h
* @date Jan 12, 2010
* @author: Frank Dellaert
* @author: Richard Roberts
*/
#pragma once
#include <list>
#include <iostream>
#include <boost/mpl/char.hpp>
#include <boost/format.hpp>
#include <boost/serialization/nvp.hpp>
#include <boost/function.hpp>
#include <boost/lambda/bind.hpp>
#include <boost/lambda/construct.hpp>
#include <boost/lambda/lambda.hpp>
#include <gtsam/nonlinear/Key.h>
namespace gtsam {
/**
* Character and index key used in VectorValues, GaussianFactorGraph,
* GaussianFactor, etc. These keys are generated at runtime from TypedSymbol
* keys when linearizing a nonlinear factor graph. This key is not type
* safe, so cannot be used with any Nonlinear* classes.
*/
class Symbol {
protected:
unsigned char c_;
size_t j_;
public:
/** Default constructor */
Symbol() :
c_(0), j_(0) {
}
/** Copy constructor */
Symbol(const Symbol& key) :
c_(key.c_), j_(key.j_) {
}
/** Constructor */
Symbol(unsigned char c, size_t j) :
c_(c), j_(j) {
}
/** Constructor that decodes an integer Key */
Symbol(Key key) {
const size_t keyBits = sizeof(Key) * 8;
const size_t chrBits = sizeof(unsigned char) * 8;
const size_t indexBits = keyBits - chrBits;
const Key chrMask = Key(std::numeric_limits<unsigned char>::max()) << indexBits;
const Key indexMask = ~chrMask;
c_ = (unsigned char)((key & chrMask) >> indexBits);
j_ = key & indexMask;
}
/** Cast to integer */
operator Key() const {
const size_t keyBits = sizeof(Key) * 8;
const size_t chrBits = sizeof(unsigned char) * 8;
const size_t indexBits = keyBits - chrBits;
const Key chrMask = Key(std::numeric_limits<unsigned char>::max()) << indexBits;
const Key indexMask = ~chrMask;
if(j_ > indexMask)
throw std::invalid_argument("Symbol index is too large");
Key key = (Key(c_) << indexBits) | j_;
return key;
}
// Testable Requirements
void print(const std::string& s = "") const {
std::cout << s << ": " << (std::string) (*this) << std::endl;
}
bool equals(const Symbol& expected, double tol = 0.0) const {
return (*this) == expected;
}
/** Retrieve key character */
unsigned char chr() const {
return c_;
}
/** Retrieve key index */
size_t index() const {
return j_;
}
/** Create a string from the key */
operator std::string() const {
return str(boost::format("%c%d") % c_ % j_);
}
/** Comparison for use in maps */
bool operator<(const Symbol& comp) const {
return c_ < comp.c_ || (comp.c_ == c_ && j_ < comp.j_);
}
bool operator==(const Symbol& comp) const {
return comp.c_ == c_ && comp.j_ == j_;
}
bool operator!=(const Symbol& comp) const {
return comp.c_ != c_ || comp.j_ != j_;
}
/** Return a filter function that returns true when evaluated on a Key whose
* character (when converted to a Symbol) matches \c c. Use this with the
* Values::filter() function to retrieve all key-value pairs with the
* requested character.
*/
static boost::function<bool(Key)> ChrTest(unsigned char c) {
namespace bl = boost::lambda;
return bl::bind(&Symbol::chr, bl::bind(bl::constructor<Symbol>(), bl::_1)) == c;
}
private:
/** Serialization function */
friend class boost::serialization::access;
template<class ARCHIVE>
void serialize(ARCHIVE & ar, const unsigned int version) {
ar & BOOST_SERIALIZATION_NVP(c_);
ar & BOOST_SERIALIZATION_NVP(j_);
}
};
} // namespace gtsam