TwoBodyEngine computes (ab|O|cd) (i.e. More...

#include <engine.h>

Collaboration diagram for libint2::TwoBodyEngine< Kernel >:

Classes
struct	class_id

struct	class_profile

Public Types
typedef libint2::TwoBodyEngineTraits< Kernel >::oper_params_type	oper_params_type

Public Member Functions
	TwoBodyEngine ()
	creates a default (unusable) TwoBodyEngine

	TwoBodyEngine (size_t max_nprim, int max_l, int deriv_order=0, real_t precision=std::numeric_limits< real_t >::epsilon(), const oper_params_type &oparams=oper_params_type())
	Constructs a (usable) TwoBodyEngine. More...

	TwoBodyEngine (TwoBodyEngine &&other)
	move constructor

	TwoBodyEngine (const TwoBodyEngine &other)
	(deep) copy constructor

TwoBodyEngine &	operator= (TwoBodyEngine &&other)
	move assignment

TwoBodyEngine &	operator= (const TwoBodyEngine &other)
	(deep) copy assignment

const real_t *	compute (const libint2::Shell &tbra1, const libint2::Shell &tbra2, const libint2::Shell &tket1, const libint2::Shell &tket2)
	computes shell set of integrals More...

void	set_precision (real_t prec)
	this specifies target precision for computing the integrals. More...

real_t	precision () const

void	print_timers ()

Public Attributes
Timers< 3 >	timers

std::map< class_id, class_profile >	class_profiles

Static Public Attributes
static bool	skip_core_ints = false

Friends
struct	detail::TwoBodyEngineDispatcher< Kernel >

Detailed Description

template<MultiplicativeSphericalTwoBodyKernel Kernel>
class libint2::TwoBodyEngine< Kernel >

TwoBodyEngine computes (ab|O|cd) (i.e.

four-center) integrals over a two-body kernel of type MultiplicativeSphericalTwoBodyKernel using Obara-Saika-Ahlrichs relations.

Template Parameters

Kernel kernel type, the supported values are enumerated by MultiplicativeSphericalTwoBodyKernel

Constructor & Destructor Documentation

template<MultiplicativeSphericalTwoBodyKernel Kernel>

libint2::TwoBodyEngine< Kernel >::TwoBodyEngine	(	size_t	max_nprim,
		int	max_l,
		int	deriv_order = `0`,
		real_t	precision = `std::numeric_limits<real_t>::epsilon()`,
		const oper_params_type &	oparams = `oper_params_type()`
	)

inline

Constructs a (usable) TwoBodyEngine.

Parameters

max_nprim	the maximum number of primitives per contracted Gaussian shell
max_l	the maximum angular momentum of Gaussian shell
deriv_order	if not 0, will compute geometric derivatives of Gaussian integrals of order `deriv_order`
precision	specifies the target precision with which the integrals will be computed; the default is the "epsilon" of `real_t` type, given by `std::numeric_limits<real_t>::epsilon()`. The precision control is somewhat empirical, hence be conservative.

See also: set_precision()

Parameters

oper_params

specifies the operator parameters. The type of oper_params depends on Kernel as follows:

Coulomb : empty type (does not need to be provided)
cGTG : ContractedGaussianGeminal
cGTG_times_Coulomb : ContractedGaussianGeminal
DelcGTG_square : ContractedGaussianGeminal

Warning: currently derivative integrals are not supported; currently only one-contraction Shell objects are supported; i.e. generally-contracted Shells are not yet supported

Member Function Documentation

template<MultiplicativeSphericalTwoBodyKernel Kernel>

const real_t* libint2::TwoBodyEngine< Kernel >::compute	(	const libint2::Shell &	tbra1,
		const libint2::Shell &	tbra2,
		const libint2::Shell &	tket1,
		const libint2::Shell &	tket2
	)

inline

computes shell set of integrals

Note: result is stored in the "chemists" form, i.e. (tbra1 tbra2 |tket1 tket2), in row-major order

References libint2::Shell::contr, libint2::Timers< N >::start(), and libint2::Timers< N >::stop().

template<MultiplicativeSphericalTwoBodyKernel Kernel>

real_t libint2::TwoBodyEngine< Kernel >::precision ( ) const

inline

Returns: the target precision for computing the integrals

See also: set_precision(real_t)

References libint2::Timers< N >::read(), and libint2::Timers< N >::set_now_overhead().

template<MultiplicativeSphericalTwoBodyKernel Kernel>

void libint2::TwoBodyEngine< Kernel >::set_precision ( real_t prec )

inline

this specifies target precision for computing the integrals.

target precision $\epsilon$ is used in 3 ways: (1) to screen out primitive pairs in ShellPair object for which ${\rm scr}_{12} = \max|c_1| \max|c_2| \exp(-\rho_{12} |AB|^2)/\gamma_{12} < \epsilon$ ; (2) to screen out primitive quartets outside compute_primdata() for which ${\rm scr}_{12} {\rm scr}_{34} < \epsilon$ ; (3) to screen out primitive quartets inside compute_primdata() for which the prefactor of $F_m(\rho, T)$ is smaller than $\epsilon$ .

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

engine.h

Classes

Public Types

Public Member Functions

Public Attributes

Static Public Attributes

Friends

Detailed Description

template<MultiplicativeSphericalTwoBodyKernel Kernel> class libint2::TwoBodyEngine< Kernel >

Constructor & Destructor Documentation

Member Function Documentation

template<MultiplicativeSphericalTwoBodyKernel Kernel>
class libint2::TwoBodyEngine< Kernel >