sc::R12Technology Class Reference

R12Technology describes technical features of the R12 approach. More...

#include <chemistry/qc/mbptr12/r12technology.h>

Inheritance diagram for sc::R12Technology:

[legend]

List of all members.

Public Member Functions
	R12Technology (StateIn &)
	R12Technology (const Ref< KeyVal > &, const Ref< GaussianBasisSet > &bs, const Ref< GaussianBasisSet > &vbs, const Ref< GaussianBasisSet > &abs)
	The KeyVal constructor.
void	save_data_state (StateOut &)
	Save the base classes (with save_data_state) and the members in the same order that the StateIn CTOR initializes them.
const Ref < LinearR12::CorrelationFactor > &	corrfactor () const
void	corrfactor (const Ref< LinearR12::CorrelationFactor > &)
	this changes the correlation factor
unsigned int	maxnabs () const
bool	gbc () const
bool	ebc () const
LinearR12::ABSMethod	abs_method () const
LinearR12::StandardApproximation	stdapprox () const
const Ref< LinearR12Ansatz > &	ansatz () const
bool	spinadapted () const
bool	omit_P () const
bool	pauli () const
bool	include_mp1 () const
bool	safety_check () const
const LinearR12::PositiveDefiniteB &	posdef_B () const
bool	omit_B () const
void	check_integral_factory (const Ref< Integral > &ints)
void	print (std::ostream &o=ExEnv::out0()) const
	Print the object.
Classes
struct	GTGFitWeight

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Detailed Description

R12Technology describes technical features of the R12 approach.

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Constructor & Destructor Documentation

sc::R12Technology::R12Technology	(	const Ref< KeyVal > &	,
		const Ref< GaussianBasisSet > &	bs,
		const Ref< GaussianBasisSet > &	vbs,
		const Ref< GaussianBasisSet > &	abs
	)

The KeyVal constructor.

corr_factor

This string specifies which correlation factor to use. Allowed values are "r12", "g12", "geng12", and "none". The default is "r12".

corr_param

This keyword specifies optional parameters of the correlation factor. corr_param can be a single floating-point value an array of floating-point values, or an array of arrays of 2-element arrays of floating-point values. Single value specifies the parameter of the single correlation function. The 1-d array form specifies a set of primitive correlation functions characterized by the corresponding parameters. The 3-d array form specifies a set of contracted correlation functions. For example, corr_param = 3.0 specifies a single correlation function with parameter 3.0. corr_param = [ 1.0 3.0 10.0 ] specifies 3 correlation functions with parameters 1.0, 3.0 and 10.0. corr_param = [ [[1.0 0.35][3.0 0.65]] [[10.0 1.0]] ] specifies 2 correlation functions, first composed of 2 primitive functions with parameters 1.0 and 3.0 combined linearly with coefficients 0.35 and 0.65, and second primitive function with parameter 10.0 .

This keyword has no meaning for some correlation factors, e.g., "r12" and "none", and is not used. There is no default.

stdapprox

This gives a string that must take on one of the values below. The default is A'. WARNING: standard approximation A is now obsolete.

A'

Use second order Møller-Plesset perturbation theory with linear R12 terms in standard approximation A' (MP2-R12/A'). This will cause MP2-R12/A energies to be computed also. Only energies can be computed with the MP2-R12/A' method.

A''

Use second order Møller-Plesset perturbation theory with linear R12 terms in standard approximation A'' (MP2-R12/A''). Only energies can be computed with the MP2-R12/A'' method.

B

Use second order Møller-Plesset perturbation theory with linear R12 terms in standard approximation B. This will cause A and A' energies to be computed also. Only energies can be computed with the MP2-R12/B method.

C

Use second order Møller-Plesset perturbation theory with linear R12 terms in standard approximation C. Only energies can be computed with the MP2-R12/C method.

ansatz

This object specifies the ansatz (see LinearR12Ansatz).

gbc

This boolean specifies whether Generalized Brillouin Condition (GBC) is assumed to hold. The default is "true". This keyword is only valid if stdapprox=A'. The effect of setting this keyword to true is very small -- hence it is not recommended to use this keyword.

ebc

This boolean specifies whether Extended Brillouin Condition (EBC) is assumed to hold. The default is "true". This keyword is only valid if stdapprox=A'. The effect of setting this keyword to true is small -- hence it is not recommended to use this keyword.

maxnabs

This integer specifies the maximum number of ABS indices per integral. Valid values are between 1 and 2. The default is to include all terms necessary for a given method. For example, MP2-F12/B energy involves integrals with 2 ABS indices. Setting maxnabs to 1 will leave out such terms.

abs_method

This string specifies whether the old ABS method, introduced by Klopper and Samson, or the new ABS variant, CABS, introduced by Valeev, should be used. Valid values are "ABS" (Klopper and Samson), "ABS+", "CABS", and "CABS+", where the "+" labels a method where the union of OBS and ABS is used to construct the RI basis. The default is "ABS". The default in 2.3.0 and later will be "CABS+".

safety_check

Set to true if you want to perform safety checks, e.g., for completeness of the RI basis, linear independence of the geminal basis, positive definiteness of B matrix, etc. The default is true (to perform the checks).

posdef_B

This keyword specifies whether and how to enforce the positive definiteness of matrix B. Valid choices are no, yes (enforce positive definite matrix B and its pair-dependent counterpart, tilde-B), weak (same as yes, except the positive-definiteness of tilde-B is not enforced). If this keyword is set to no then sometimes nonphysical results can be obtained, e.g., positive pair energy corrections can result from using too many correlation functions. posdef_B = yes offers the best protection against nonphysical results. The default is weak, which is cheaper yes and is definitely safer than no.

gtg_fit_weight

This keyword determines how the correlation factor is fit to Gaussians (hence only valid when corr_factor is set to stg-ng) The choices are tewklopper, which is appropriate for energy computations, and cusp, which is appropriate for accurate cusp region description. The default is tewklopper. Choosing cusp is probably only appropriate when many (9 or more) Gaussians are used for the fit.

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Member Function Documentation

void sc::R12Technology::save_data_state

(

StateOut &

)

[virtual]

Save the base classes (with save_data_state) and the members in the same order that the StateIn CTOR initializes them.

This must be implemented by the derived class if the class has data.

Reimplemented from sc::SavableState.

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

• src/lib/chemistry/qc/mbptr12/r12technology.h