gtsam  4.1.0
gtsam
gtsam::Value Class Referenceabstract

Detailed Description

This is the base class for any type to be stored in Values.

Note: As of GTSAM 4.0, Value types should no longer derive from Value or DerivedValue. Use type traits instead. See https://bitbucket.org/gtborg/gtsam/wiki/Migrating%20from%20GTSAM%203.X%20to%20GTSAM%204.0#markdown-header-custom-value-types for current usage and migration details.

+ Inheritance diagram for gtsam::Value:

Public Member Functions

virtual Valueclone_ () const =0
 Clone this value in a special memory pool, must be deleted with Value::deallocate_, not with the 'delete' operator.
 
virtual void deallocate_ () const =0
 Deallocate a raw pointer of this value.
 
virtual boost::shared_ptr< Valueclone () const =0
 Clone this value (normal clone on the heap, delete with 'delete' operator)
 
virtual bool equals_ (const Value &other, double tol=1e-9) const =0
 Compare this Value with another for equality.
 
virtual void print (const std::string &str="") const =0
 Print this value, for debugging and unit tests.
 
virtual size_t dim () const =0
 Return the dimensionality of the tangent space of this value. More...
 
virtual Valueretract_ (const Vector &delta) const =0
 Increment the value, by mapping from the vector delta in the tangent space of the current value back to the manifold to produce a new, incremented value. More...
 
virtual Vector localCoordinates_ (const Value &value) const =0
 Compute the coordinates in the tangent space of this value that retract() would map to value. More...
 
virtual Valueoperator= (const Value &)
 Assignment operator.
 
template<typename ValueType >
const ValueType & cast () const
 Cast to known ValueType.
 
virtual ~Value ()
 Virutal destructor.
 

Friends

class boost::serialization::access
 Empty serialization function. More...
 

Member Function Documentation

◆ dim()

virtual size_t gtsam::Value::dim ( ) const
pure virtual

Return the dimensionality of the tangent space of this value.

This is the dimensionality of delta passed into retract() and of the vector returned by localCoordinates().

Returns
The dimensionality of the tangent space

Implemented in gtsam::GenericValue< T >.

◆ localCoordinates_()

virtual Vector gtsam::Value::localCoordinates_ ( const Value value) const
pure virtual

Compute the coordinates in the tangent space of this value that retract() would map to value.

Parameters
valueThe value whose coordinates should be determined in the tangent space of the value on which this function is called.
Returns
The coordinates of value in the tangent space of this.

Implemented in gtsam::GenericValue< T >.

◆ retract_()

virtual Value* gtsam::Value::retract_ ( const Vector &  delta) const
pure virtual

Increment the value, by mapping from the vector delta in the tangent space of the current value back to the manifold to produce a new, incremented value.

Parameters
deltaThe delta vector in the tangent space of this value, by which to increment this value.

Implemented in gtsam::GenericValue< T >.

Friends And Related Function Documentation

◆ boost::serialization::access

friend class boost::serialization::access
friend

Empty serialization function.

There are two important things that users need to do to serialize derived objects in Values successfully: (Those derived objects are stored in Values as pointer to this abstract base class Value)

1. All DERIVED classes derived from Value must put the following line in their serialization function:
  \code
     ar & boost::serialization::make_nvp("DERIVED", boost::serialization::base_object<Value>(*this));
 \endcode
  or, alternatively
  \code
     ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(Value);
 \endcode
  See: http://www.boost.org/doc/libs/release/libs/serialization/doc/serialization.html#runtimecasting

2. The source module that includes archive class headers to serialize objects of derived classes
 (boost/archive/text_oarchive.h, for example) must *export* all derived classes, using either
 BOOST_CLASS_EXPORT or BOOST_CLASS_EXPORT_GUID macros:
      \code
     BOOST_CLASS_EXPORT(DERIVED_CLASS_1)
     BOOST_CLASS_EXPORT_GUID(DERIVED_CLASS_2, "DERIVED_CLASS_2_ID_STRING")
      \endcode
  See:   http://www.boost.org/doc/libs/release/libs/serialization/doc/serialization.html#derivedpointers
        http://www.boost.org/doc/libs/release/libs/serialization/doc/serialization.html#export
        http://www.boost.org/doc/libs/release/libs/serialization/doc/serialization.html#instantiation\
        http://www.boost.org/doc/libs/release/libs/serialization/doc/special.html#export
        http://www.boost.org/doc/libs/release/libs/serialization/doc/traits.html#export
  The last two links explain why these export lines have to be in the same source module that includes
  any of the archive class headers.

The documentation for this class was generated from the following files: