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.

	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.

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.

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.

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

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.

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.

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.

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
	Return 1 if the object is managed. Otherwise return 0.

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.

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.

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

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.

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()