Decomposition by density fitting with respect to some kernel. More...

#include <chemistry/qc/lcao/df.h>

Inheritance diagram for sc::DensityFitting:

Public Types
enum	SolveMethod { SolveMethod_InverseCholesky = 0, SolveMethod_Cholesky = 1, SolveMethod_RefinedCholesky = 2, SolveMethod_InverseBunchKaufman = 3, SolveMethod_BunchKaufman = 4, SolveMethod_RefinedBunchKaufman = 5 }

typedef TwoBodyMOIntsRuntimeUnion23	MOIntsRuntime

Public Member Functions
	DensityFitting (const Ref< MOIntsRuntime > &rtime, const std::string &kernel_key, SolveMethod solver, const Ref< OrbitalSpace > &space1, const Ref< OrbitalSpace > &space2, const Ref< GaussianBasisSet > &fitting_basis, bool ri=false)
	Determines density fitting of product (space1 space2) in terms of fitting basis. More...

	DensityFitting (StateIn &)

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. More...

const Ref< MOIntsRuntime > &	runtime () const

const Ref< Integral > &	integral () const

const Ref< OrbitalSpace > &	space1 () const

const Ref< OrbitalSpace > &	space2 () const

const Ref< GaussianBasisSet > &	fbasis () const

const std::string &	kernel_key () const

SolveMethod	solver () const

const Ref< DistArray4 > &	C () const
	returns the fitting coeffcients

RefSCDimension	product_dimension () const
	produces RefSCDimension that corresponds to the product space

virtual void	compute ()

Public Member Functions inherited from sc::SavableState
SavableState &	operator= (const SavableState &)

void	save_state (StateOut &)
	Save the state of the object as specified by the StateOut object. More...

void	save_object_state (StateOut &)
	This can be used for saving state when the exact type of the object is known for both the save and the restore. More...

virtual void	save_vbase_state (StateOut &)
	Save the virtual bases for the object. More...

Public Member Functions inherited from sc::DescribedClass
	DescribedClass (const DescribedClass &)

DescribedClass &	operator= (const DescribedClass &)

ClassDesc *	class_desc () const MPQC__NOEXCEPT
	This returns the unique pointer to the ClassDesc corresponding to the given type_info object. More...

const char *	class_name () const
	Return the name of the object's exact type.

int	class_version () const
	Return the version of the class.

virtual void	print (std::ostream &=ExEnv::out0()) const
	Print the object.

Ref< DescribedClass >	ref ()
	Return this object wrapped up in a Ref smart pointer. More...

Public Member Functions inherited from sc::RefCount
size_t	identifier () const
	Return the unique identifier for this object that can be compared for different objects of different types. More...

int	lock_ptr () const
	Lock this object.

int	unlock_ptr () const
	Unlock this object.

void	use_locks (bool inVal)
	start and stop using locks on this object

refcount_t	nreference () const
	Return the reference count.

refcount_t	reference ()
	Increment the reference count and return the new count.

refcount_t	dereference ()
	Decrement the reference count and return the new count.

int	managed () const

void	unmanage ()
	Turn off the reference counting mechanism for this object. More...

Static Public Member Functions
static int	definite_kernel (TwoBodyOper::type kernel_type, const Ref< IntParams > &kernel_params)
	Test whether a density-fitting kernel has definite sign. More...

static int	definite_kernel (TwoBodyOper::type kernel_type, const std::string &kernel_params_key)

Static Public Member Functions inherited from sc::SavableState
static void	save_state (SavableState *s, StateOut &)

static SavableState *	restore_state (StateIn &si)
	Restores objects saved with save_state. More...

static SavableState *	key_restore_state (StateIn &si, const char *keyword)
	Like restore_state, but keyword is used to override values while restoring.

static SavableState *	dir_restore_state (StateIn &si, const char objectname, const char keyword=0)

Protected Member Functions
const RefSymmSCMatrix &	kernel () const
	returns the kernel matrix in the fitting basis, i.e. $(A\|\hat{W}\|B)$ .

const Ref< DistArray4 > &	conjugateC () const
	returns the conjugate expansion matrix defined as $\tilde{C}^{rs}_A \equiv (A\|\hat{W}\|rs) = \sum_B C^{rs}_B (A\|\hat{W}\|B)$ . More...

Protected Member Functions inherited from sc::SavableState
	SavableState (const SavableState &)

	SavableState (StateIn &)
	Each derived class StateIn CTOR handles the restore corresponding to calling save_object_state, save_vbase_state, and save_data_state listed above. More...

Protected Member Functions inherited from sc::RefCount
	RefCount (const RefCount &)

RefCount &	operator= (const RefCount &)

Protected Attributes
Ref< DistArray4 >	C_

RefSymmSCMatrix	kernel_

Ref< DistArray4 >	cC_

Detailed Description

Decomposition by density fitting with respect to some kernel.

The definition is as follows:

$|rs) = \sum_A C^{rs}_A |A) \quad ,$

where $ |A) $ belong to a fitting basis and $C^{rs}_A$ are determined by solving the linear system

$(A|\hat{W}|rs) = \sum_B C^{rs}_B (A|\hat{W}|B) \quad .$

The kernel $\hat{W}$ is any (positive-definite) operator.

Parameters

runtime	is the MOIntsRuntime object used to compute MO/AO integrals
kernel_key	denotes the kernel operator to be used for fitting. Currently only "1/r_{12}" is supported.
space1	is space r in \|rs) product space
space2	is space s in \|rs) product space
fitting_basis	is the basis set in which to perform the fitting

Constructor & Destructor Documentation

◆ DensityFitting()

sc::DensityFitting::DensityFitting	(	const Ref< MOIntsRuntime > &	rtime,
		const std::string &	kernel_key,
		SolveMethod	solver,
		const Ref< OrbitalSpace > &	space1,
		const Ref< OrbitalSpace > &	space2,
		const Ref< GaussianBasisSet > &	fitting_basis,
		bool	ri = `false`
	)

Determines density fitting of product (space1 space2) in terms of fitting basis.

Parameters

rtime
kernel_key
solver
space1
space2
fitting_basis
ri	false -> compute DF coeficients, true -> compute DF coefficients multiplied by the inverse square root of the fitting matrix (or of the matrix scaled by -1, for negative-definite kernels); only supported if using inverse-based Cholesky solver.

Returns

Member Function Documentation

◆ conjugateC()

const Ref<DistArray4>& sc::DensityFitting::conjugateC ( ) const

inlineprotected

returns the conjugate expansion matrix defined as $\tilde{C}^{rs}_A \equiv (A|\hat{W}|rs) = \sum_B C^{rs}_B (A|\hat{W}|B)$ .

$\tilde{C}$ is conjugate to $ C $ in the sense that their product returns reconstructed integrals: $(pq|rs) \approx \sum_A \tilde{C}^A_{pq} C^{rs}_A$

◆ definite_kernel()

static int sc::DensityFitting::definite_kernel	(	TwoBodyOper::type	kernel_type,
		const Ref< IntParams > &	kernel_params
	)

static

Test whether a density-fitting kernel has definite sign.

Note: this is a preliminary implementation that makes common assumptions about the kernel_params argument

Parameters

kernel_type	kernel type; only some operators are accepted as density fitting kernel
kernel_params	kernel parameters; must be in ParamsRegistry

Returns: +1 if the kernel is positive-definite, -1 if the kernel is negative-definite, 0 otherwise

◆ save_data_state()

void sc::DensityFitting::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.

Reimplemented in sc::PermutedDensityFitting, and sc::TransformedDensityFitting.

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

src/lib/chemistry/qc/lcao/df.h

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ DensityFitting()

Member Function Documentation

◆ conjugateC()

◆ definite_kernel()

◆ save_data_state()