State Class Reference

A State object records a snapshot of the current state of a simulation at a point in time. More...

#include <State.h>

Inheritance diagram for State:

Public Types
enum	DataType {   Positions =1, Velocities =2, Forces =4, Energy =8,   Parameters =16 }
	This is an enumeration of the types of data which may be stored in a State. More...

Public Member Functions
	State ()
	Construct an empty State containing no data.
double	getTime () const
	Get the time for which this State was created.
const std::vector< Vec3 > &	getPositions () const
	Get the position of each particle.
const std::vector< Vec3 > &	getVelocities () const
	Get the velocity of each particle.
const std::vector< Vec3 > &	getForces () const
	Get the force acting on each particle.
double	getKineticEnergy () const
	Get the total kinetic energy of the system.
double	getPotentialEnergy () const
	Get the total potential energy of the system.
void	getPeriodicBoxVectors (Vec3 &a, Vec3 &b, Vec3 &c) const
	Get the vectors defining the axes of the periodic box (measured in nm).
double	getPeriodicBoxVolume () const
	Get the volume of the periodic box (measured in nm^3).
const std::map< std::string, double > &	getParameters () const
	Get a map containing the values of all parameters.
	StateBuilder (double time)
State	getState ()
void	setPositions (const std::vector< Vec3 > &pos)
void	setVelocities (const std::vector< Vec3 > &vel)
void	setForces (const std::vector< Vec3 > &force)
void	setParameters (const std::map< std::string, double > &params)
void	setEnergy (double ke, double pe)
void	setPeriodicBoxVectors (const Vec3 &a, const Vec3 &b, const Vec3 &c)

Detailed Description

A State object records a snapshot of the current state of a simulation at a point in time.

Internal class used to construct new State objects.

You create it by calling getState() on a Context.

When a State is created, you specify what information should be stored in it. This saves time and memory by only copying in the information that you actually want. This is especially important for forces and energies, since they may need to be calculated. If you query a State object for a piece of information which is not available (because it was not requested when the State was created), it will throw an exception.

Member Enumeration Documentation

enum DataType

This is an enumeration of the types of data which may be stored in a State.

When you create a State, use these values to specify which data types it should contain.

Enumerator:

Positions
Velocities
Forces
Energy
Parameters

Constructor & Destructor Documentation

State

(

)

Construct an empty State containing no data.

This exists so State objects can be used in STL containers.

Member Function Documentation

const std::vector<Vec3>& getForces

(

)

const

Get the force acting on each particle.

If this State does not contain forces, this will throw an exception.

double getKineticEnergy

(

)

const

Get the total kinetic energy of the system.

If this State does not contain energies, this will throw an exception.

Note that this may be different from simply mv²/2 summed over all particles. For example, a leapfrog integrator will store velocities offset by half a step, so they must be adjusted before computing the kinetic energy. This routine returns the kinetic energy at the current time, computed in a way that is appropriate for whatever Integrator is being used.

const std::map<std::string, double>& getParameters

(

)

const

Get a map containing the values of all parameters.

If this State does not contain parameters, this will throw an exception.

void getPeriodicBoxVectors	(	Vec3 &	a,
		Vec3 &	b,
		Vec3 &	c
	)		const

Get the vectors defining the axes of the periodic box (measured in nm).

Parameters

a	on exit, this contains the vector defining the first edge of the periodic box
b	on exit, this contains the vector defining the second edge of the periodic box
c	on exit, this contains the vector defining the third edge of the periodic box

double getPeriodicBoxVolume

(

)

const

Get the volume of the periodic box (measured in nm^3).

const std::vector<Vec3>& getPositions

(

)

const

Get the position of each particle.

If this State does not contain positions, this will throw an exception.

double getPotentialEnergy

(

)

const

Get the total potential energy of the system.

If this State does not contain energies, this will throw an exception.

State getState

(

)

double getTime

(

)

const

Get the time for which this State was created.

const std::vector<Vec3>& getVelocities

(

)

const

Get the velocity of each particle.

If this State does not contain velocities, this will throw an exception.

void setEnergy	(	double	ke,
		double	pe
	)

void setForces

(

const std::vector< Vec3 > &

force

)

void setParameters

(

const std::map< std::string, double > &

params

)

void setPeriodicBoxVectors	(	const Vec3 &	a,
		const Vec3 &	b,
		const Vec3 &	c
	)

void setPositions

(

const std::vector< Vec3 > &

pos

)

void setVelocities

(

const std::vector< Vec3 > &

vel

)

StateBuilder

(

double

time

)

---

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

• State.h