ExCorr Class Reference

Exchange-Correlation energy calculator. More...

#include <ExCorr.h>

Classes
struct	OrbitalDep
	Abstract base class (interface specification) for orbital-dependent potential functionals. More...

Public Member Functions
	ExCorr (ExCorrType exCorrType=ExCorrGGA_PBE, KineticType kineticType=KineticNone)
void	setup (const Everything &)
	Initialize.
string	getName () const
	Get a description of the DFT functional.
double	operator() (const ScalarFieldArray &n, ScalarFieldArray *Vxc=0, IncludeTXC includeTXC=IncludeTXC(), const ScalarFieldArray *tau=0, ScalarFieldArray *Vtau=0, matrix3<> *Exc_RRT=0) const
double	operator() (const ScalarField &n, ScalarField *Vxc=0, IncludeTXC includeTXC=IncludeTXC(), const ScalarField *tau=0, ScalarField *Vtau=0, matrix3<> *Exc_RRT=0) const
	Unpolarized wrapper to above function.
double	exxFactor () const
	retrieve the exact exchange scale factor (0 if no exact exchange)
double	exxRange () const
	range parameter (omega) for screened exchange (0 for long-range exchange)
bool	needsKEdensity () const
	whether orbital KE density is required as an input (for meta GGAs)
bool	hasEnergy () const
	whether functional supports a total energy (if not, only usable in SCF, and no forces)
void	getSecondDerivatives (const ScalarField &n, ScalarField &e_nn, ScalarField &e_sigma, ScalarField &e_nsigma, ScalarField &e_sigmasigma, double nCut=1e-4, ScalarField *sigma_alt=0) const
void	get_dVxc (const ScalarFieldArray &n, ScalarFieldArray *dVxc, IncludeTXC includeTXC, const ScalarFieldArray *tauPtr, ScalarFieldArray *Vtau, const ScalarFieldArray &dn) const
	Get change in Vxc due to change in density dn.
bool	needFiniteDifference_dVxc () const

Public Attributes
std::shared_ptr< OrbitalDep >	orbitalDep

Friends
struct	CommandElecExCorr
struct	CommandFluidExCorr
struct	CommandExchangeParameters

Detailed Description

Exchange-Correlation energy calculator.

Member Function Documentation

getSecondDerivatives()

void ExCorr::getSecondDerivatives	(	const ScalarField &	n,
		ScalarField &	e_nn,
		ScalarField &	e_sigma,
		ScalarField &	e_nsigma,
		ScalarField &	e_sigmasigma,
		double	nCut = 1e-4,
		ScalarField *	sigma_alt = 0
	)		const

Compute second derivatives of energy density w.r.t n and sigma=|grad n|^2 by finite difference (supported only for spin-unpolarized internal LDAs and GGAs). All sigma derivatives will be null on output for LDAs. The gradients will be set to zero for regions with n < nCut (useful to reduce numerical sensitivity in systems with empty space) By default, sigma will be computed from n, but this can be overridden by specifying sigma_alt.

operator()()

double ExCorr::operator()	(	const ScalarFieldArray &	n,
		ScalarFieldArray *	Vxc = 0,
		IncludeTXC	includeTXC = IncludeTXC(),
		const ScalarFieldArray *	tau = 0,
		ScalarFieldArray *	Vtau = 0,
		matrix3<> *	Exc_RRT = 0
	)		const

Compute the exchange-correlation energy (and optionally gradient) for a (spin) density n. includeTXC selects which components to include in result (XC without kinetic by default). Orbital KE density tau must be provided if needsKEdensity() is true (for meta GGAs) and the corresponding gradient will be returned in Vtau if non-null For metaGGAs, Vtau should be non-null if Vxc is non-null Optionally compute stress due to XC if Exc_RRT is non-null

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

• electronic/ExCorr.h