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 modified directly (not through e.g., an Optimizer), until Model::update() or Model::evaluate() have been called. For example, if you change a particle's coordinates, a IMP::core::Centroid of a set of particles that contains the particle, will not be the correct centroid until the Model is updated.

Definition at line 49 of file Constraint.h.

Public Member Functions
	Constraint (Model *m, std::string name="Constraint %1%")

virtual void	do_after_evaluate (DerivativeAccumulator *da) override
	Do any necessary updates after the model score is calculated. More...

virtual void	do_before_evaluate () override
	Update the state given the current state of the model. More...

virtual void	do_update_attributes ()=0

virtual void	do_update_derivatives (DerivativeAccumulator *da)=0

Public Member Functions inherited from IMP::ScoreState
	ScoreState (Model *m, std::string name)

void	after_evaluate (DerivativeAccumulator *accpt)
	Do post evaluation work if needed. More...

void	before_evaluate ()
	Force update of the structure. More...

bool	get_can_skip () const
	Get whether this state can be skipped if its inputs/outputs didn't move. More...

Public Member Functions inherited from IMP::ModelObject
	ModelObject (Model *m, std::string name)

bool	get_has_dependencies () const
	Return whether this object has dependencies computed. More...

bool	get_has_required_score_states () const
	Return whether score states are computed. More...

ModelObjectsTemp	get_inputs () const

ModelObjectsTemps	get_interactions () const
	Get the interacting sets induced by this ModelObject. More...

Model *	get_model () const

ModelObjectsTemp	get_outputs () const

const ScoreStatesTemp &	get_required_score_states () const
	Get the score states that are ancestors of this in the dependency graph. More...

void	set_has_dependencies (bool tf)
	Either invalidate the dependencies or ensure they are correct. More...

void	set_has_required_score_states (bool tf)
	Compute the required score states. More...

Public Member Functions inherited from IMP::Object
virtual void	clear_caches ()

CheckLevel	get_check_level () const

LogLevel	get_log_level () const

virtual VersionInfo	get_version_info () const
	Get information about the module and version of the object. More...

void	set_check_level (CheckLevel l)

void	set_log_level (LogLevel l)
	Set the logging level used in this object. More...

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)

virtual std::string	get_type_name () const

Additional Inherited Members
Protected Member Functions inherited from IMP::ScoreState
void	set_can_skip (bool can_skip)
	Set whether we can skip during model evaluation if appropriate. More...

Protected Member Functions inherited from IMP::ModelObject
virtual ModelObjectsTemp	do_get_inputs () const =0

virtual ModelObjectsTemps	do_get_interactions () const

virtual ModelObjectsTemp	do_get_outputs () const =0

virtual void	handle_set_has_required_score_states (bool)

Protected Member Functions inherited from IMP::Object
	Object (std::string name)
	Construct an object with the given name. More...

virtual void	do_destroy ()