IMP::Constraint Class Reference

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Detailed Description

Implement a constraint on the Model.

The solution model can be restricted two ways, either by penalizing "bad" conformations (a restraint) or by forcing some set of attributes to a function of other attributes (a constraint). For example, rigid bodies consisting of a number of particles could be implemented either way.

• As a restraint: the particles in the rigid body are each moved independently by the optimizer. The scoring function has a term for how far each particle diverges from its rigid position.

• As a constraint: the optimizer only changes the position of the rigid body itself and the position of the particles in the body are computed from the position of the rigid body.

In IMP, constraints are implemented as a type of ScoreState. Before evaluation, the constraint updates the attributes of some of the particles to ensure that the constraint is satisfied. Since this update creates implicit relationships between the particles, after the derivatives are computed, the constraint can move them around to make sure the derivatives of the optimizer parameters are correct.

In general, constraints are associated with Decorator objects and created invisibly when needed.

Note:

Constraint invariants will not necessarily hold if involved particles have been called and Model::evaluate() has not been called. For example, if you change a particle's coordinates, a IMP::core::Centroid of a set containing the particle will not be correct until the Model is evaluated.

Implementors

Developers who wish to implement a Constraint should inherit from this class and use the IMP_CONSTRAINT() macro to help define the needed functions. Lamentably, we do not provide an example.

Inheritance diagram for IMP::Constraint:

List of all members.

Public Member Functions
	Constraint (Model *m, std::string name="Constraint %1%")
Public Member Functions inherited from IMP::ScoreState
	ScoreState (Model *m, std::string name="ScoreState %1%")
void	after_evaluate (DerivativeAccumulator *accpt)
void	before_evaluate ()
virtual ContainersTemp	get_input_containers () const =0
virtual ContainersTemp	get_output_containers () const =0
virtual ParticlesTemp	get_input_particles () const =0
virtual ParticlesTemp	get_output_particles () const =0
Public Member Functions inherited from IMP::ModelObject
	ModelObject (Model *m, std::string name)
ModelObjectsTemp	get_inputs () const
Model *	get_model () const
ModelObjectsTemp	get_outputs () const
Public Member Functions inherited from IMP::base::Object
std::size_t	__hash__ () const
virtual std::string	get_type_name () const =0
	Return a string identifying the type of the object.
virtual IMP::base::VersionInfo	get_version_info () const =0
	Get information about the module and version of the object.
void	set_check_level (CheckLevel l)
void	set_log_level (LogLevel l)
	Set the logging level used in this object.
void	set_was_used (bool tf) const
void	show (std::ostream &out=std::cout) const
const std::string &	get_name () const
void	set_name (std::string name)

Additional Inherited Members
Protected Member Functions inherited from IMP::ScoreState
virtual void	do_after_evaluate (DerivativeAccumulator *accpt)=0
virtual void	do_before_evaluate ()=0
Protected Member Functions inherited from IMP::ModelObject
virtual ModelObjectsTemp	do_get_inputs () const =0
virtual ModelObjectsTemp	do_get_outputs () const =0
virtual void	do_update_dependencies (const DependencyGraph &, const DependencyGraphVertexIndex &)
void	update_dependencies (const DependencyGraph &dg, const DependencyGraphVertexIndex &index)
Protected Member Functions inherited from IMP::base::Object
	Object (std::string name)

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

• Constraint.h