Package etomica.potential

Class Potential2SoftSpherical

java.lang.Object

etomica.potential.Potential

etomica.potential.Potential2

etomica.potential.Potential2SoftSpherical

All Implemented Interfaces:

IPotential, IPotentialAtomic, Potential2Soft, Potential2Spherical, PotentialSoft

Direct Known Subclasses:

P2Anharmonic, P2ArgonAziz1993, P2ArgonSlavicekEtAl2003, P2ArgonTangAndToennies2003, P2Cohesion, P2DiscreteFeynmanHibbs.P2HeEmpericalQuantum, P2Dreiding, P2Electrostatic, P2ElectrostaticWithHardCore, P2Exp6, P2Exp6Buckingham, P2Fene, P2Harmonic, P2HC2Yukawa, P2HePCJS, P2HePCKLJS, P2HeSimplified, P2HydrogenPatkowskiIso, P2LennardJones, P2LennardJonesDreiding, P2LJQQ, P2ModifiedMorse, P2Morse, P2QChemInterpolated, P2RepRowley, P2SoftSphere, P2SoftSphericalTruncated, P2WCA, P2Yukawa

public abstract class Potential2SoftSpherical
extends Potential2
implements Potential2Soft

Methods for a soft (non-impulsive), spherically-symmetric pair potential. Subclasses must provide concrete definitions for the energy (method u(double)) and its derivatives.

Field Summary

Fields

Modifier and Type	Field	Description
protected Boundary	boundary
protected Vector	dr
protected Vector[]	gradient

Fields inherited from class etomica.potential.Potential

space

Constructor Summary

Constructors

Constructor	Description
Potential2SoftSpherical(Space space)

Method Summary

Modifier and Type	Method	Description
abstract double	d2u(double r2)	The second derivative of the pair energy, times the square of the separation: r^2 d^2u/dr^2.
abstract double	du(double r2)	The derivative of the pair energy, times the separation r: r du/dr.
double	energy(IAtomList atoms)	Energy of the pair as given by the u(double) method
double	getRange()	Returns infinity.
Vector[]	gradient(IAtomList atoms)	Gradient of the pair potential as given by the du(double) method.
Vector[]	gradient(IAtomList atoms, Tensor pressureTensor)	Returns the same gradient as gradient(AtomSet) and also adds in the contribution of the AtomSet to the pressureTensor.
double	hyperVirial(IAtomList atoms)	Hypervirial of the pair as given by the du(double) and d2u(double) methods
double	integral(double rC)	Same as uInt.
void	setBox(Box box)	Informs the potential of the box on which it acts.
abstract double	uInt(double rC)	Integral of the potential, used to evaluate corrections for potential truncation.
double	virial(IAtomList atoms)	Virial of the pair as given by the du(double) method

Methods inherited from interface etomica.potential.IPotential

nBody

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from class etomica.potential.Potential

nBody

Methods inherited from interface etomica.potential.Potential2Spherical

u

Field Detail

gradient

protected final Vector[] gradient

boundary

protected Boundary boundary

dr

protected final Vector dr

Constructor Detail

Potential2SoftSpherical

public Potential2SoftSpherical(Space space)

Method Detail

du

public abstract double du(double r2)

The derivative of the pair energy, times the separation r: r du/dr.

Specified by:

du in interface Potential2Soft

d2u

public abstract double d2u(double r2)

The second derivative of the pair energy, times the square of the separation: r^2 d^2u/dr^2.

uInt

public abstract double uInt(double rC)

Integral of the potential, used to evaluate corrections for potential truncation. Specifically, this is the integral from rC (the argument) to infinity of u(r) A r^(D-1), where D is the spatial dimension, and A is the area of a unit sphere in D dimensions. Normally, the long-range potential correction would be obtained by multiplying this quantity by the pair density nPairs/V, where nPairs is the number of pairs of atoms affected by this potential, and V is the volume they occupy.

energy

public double energy(IAtomList atoms)

Energy of the pair as given by the u(double) method

Specified by:

energy in interface IPotentialAtomic

Specified by:

energy in class Potential

virial

public double virial(IAtomList atoms)

Virial of the pair as given by the du(double) method

Specified by:

virial in interface PotentialSoft

hyperVirial

public double hyperVirial(IAtomList atoms)

Hypervirial of the pair as given by the du(double) and d2u(double) methods

Specified by:

hyperVirial in interface Potential2Soft

gradient

public Vector[] gradient(IAtomList atoms)

Gradient of the pair potential as given by the du(double) method.

Specified by:

gradient in interface PotentialSoft

Returns:

gradient

public Vector[] gradient(IAtomList atoms,
                         Tensor pressureTensor)

Description copied from interface: PotentialSoft

Returns the same gradient as gradient(AtomSet) and also adds in the contribution of the AtomSet to the pressureTensor. Their contribution is added to the given Tensor. This combined method exists for computational efficiency. Calculating the pressureTensor is generally trivial once the gradient is known but often requires intermediate information.

Specified by:

gradient in interface PotentialSoft

integral

public double integral(double rC)

Same as uInt.

Specified by:

integral in interface Potential2Soft

getRange

public double getRange()

Returns infinity. May be overridden to define a finite-ranged potential.

Specified by:

getRange in interface IPotential

Specified by:

getRange in class Potential

setBox

public void setBox(Box box)

Description copied from class: Potential

Informs the potential of the box on which it acts. Typically this requires at least that it update the nearestImageTransformer of its coordinatePair (if it uses one), e.g.: cPair.setNearestImageTransformer(box.boundary());

Specified by:

setBox in interface IPotential

Specified by:

setBox in class Potential