#include <DMRGSCFintegrals.h>

Public Member Functions
	DMRGSCFintegrals (DMRGSCFindices *iHandler)
	Constructor. More...

virtual	~DMRGSCFintegrals ()
	Destructor.

void	clear ()
	Set the storage objects to zero.

void	set_coulomb (const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2, const double val)
	Set an element of the Coulomb object ( c1 c2 \| a1 a2 ) More...

void	add_coulomb (const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2, const double val)
	Add a double to an element of the Coulomb object ( c1 c2 \| a1 a2 ) More...

double	get_coulomb (const int Ic1, const int Ic2, const int Ia1, const int Ia2, const int c1, const int c2, const int a1, const int a2) const
	Get an element of the Coulomb object ( c1 c2 \| a1 a2 ) More...

void	set_exchange (const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2, const double val)
	Set an element of the Exchange object ( c1 v1 \| c2 v2 ) More...

void	add_exchange (const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2, const double val)
	Add a double to an element of the Exchange object ( c1 v1 \| c2 v2 ) More...

double	get_exchange (const int Ic1, const int Ic2, const int Iv1, const int Iv2, const int c1, const int c2, const int v1, const int v2) const
	Get an element of the Exchange object ( c1 v1 \| c2 v2 ) More...

double	FourIndexAPI (const int I1, const int I2, const int I3, const int I4, const int index1, const int index2, const int index3, const int index4) const
	Get a two-body matrix element with at most 2 virtual indices, using the FourIndex API. More...

Detailed Description

DMRGSCFintegrals class.

Author: Sebastian Wouters sebas.nosp@m.tian.nosp@m.woute.nosp@m.rs@g.nosp@m.mail..nosp@m.com

Date: January 27, 2015

Container class for rotated DMRGSCF integrals. At most two virtual indices are needed to compute the gradient and Hessian, which allows for computational as well as memory savings. The integrals are stored in two objects:

$\begin{eqnarray*} Coulomb & : & ( c_1 c_2 | a_1 a_2 ) \\ Exchange & : & ( c_1 v_1 | c_2 v_2 ) \end{eqnarray*}$

where $c$ denote core (occupied + active) orbitals, $v$ virtual orbitals, and $a$ both core and virtual orbitals. For the Coulomb integrals the fourfold permutation symmetry $c_1 \leq c_2$ and $a_1 \leq a_2$ is taken into account and for the exchange integrals the twofold permutation symmetry $c_1 \leq c_2$ .

Consider for example a molecule in C1 symmetry with 100 core (occupied + active) and 300 virtual orbitals. The FourIndex class needs to store $\frac{1}{8}(N_{core} + N_{virt})^4$ doubles or 25.6 GB. This class needs to store $\frac{1}{4} N_{core}^2 (N_{core}+N_{virt})^2 + \frac{1}{2} N_{core}^2 N_{virt}^2$ doubles or 6.8 GB. The eightfold permutation symmetry of the $( c_1 c_2 | c_3 c_4 )$ part of the Coulomb object is not used in this class. For the example, this would however only result in a reduction of $\frac{1}{8} N_{core}^4$ doubles or 0.1 GB.

Definition at line 39 of file DMRGSCFintegrals.h.

Constructor & Destructor Documentation

CheMPS2::DMRGSCFintegrals::DMRGSCFintegrals ( DMRGSCFindices * iHandler )

Constructor.

Parameters

iHandler The DMRGSCFindices which contain information on the core (occupied + active) and virtual spaces

Definition at line 24 of file DMRGSCFintegrals.cpp.

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Member Function Documentation

void CheMPS2::DMRGSCFintegrals::add_coulomb	(	const int	Ic1,
		const int	Ic2,
		const int	Ia1,
		const int	Ia2,
		const int	c1,
		const int	c2,
		const int	a1,
		const int	a2,
		const double	val
	)

Add a double to an element of the Coulomb object ( c1 c2 | a1 a2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Ia1	The irrep of the first core+virtual index
Ia2	The irrep of the second core+virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
a1	The first core+virtual index (within the irrep block)
a2	The second core+virtual index (within the irrep block)
val	The value with which the element should be augmented

Definition at line 188 of file DMRGSCFintegrals.cpp.

void CheMPS2::DMRGSCFintegrals::add_exchange	(	const int	Ic1,
		const int	Ic2,
		const int	Iv1,
		const int	Iv2,
		const int	c1,
		const int	c2,
		const int	v1,
		const int	v2,
		const double	val
	)

Add a double to an element of the Exchange object ( c1 v1 | c2 v2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Iv1	The irrep of the first virtual index
Iv2	The irrep of the second virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
v1	The first virtual index (within the irrep block; counting starts at NCORE[ Iv1 ])
v2	The second virtual index (within the irrep block; counting starts at NCORE[ Iv2 ])
val	The value with which the element should be augmented

Definition at line 233 of file DMRGSCFintegrals.cpp.

double CheMPS2::DMRGSCFintegrals::FourIndexAPI	(	const int	I1,
		const int	I2,
		const int	I3,
		const int	I4,
		const int	index1,
		const int	index2,
		const int	index3,
		const int	index4
	)		const

Get a two-body matrix element with at most 2 virtual indices, using the FourIndex API.

Parameters

I1	The irrep of the first index
I2	The irrep of the second index
I3	The irrep of the third index
I4	The irrep of the fourth index
index1	The first index (within the irrep block)
index2	The second index (within the irrep block)
index3	The third index (within the irrep block)
index4	The fourth index (within the irrep block)

Returns: The desired two-body matrix element

Definition at line 245 of file DMRGSCFintegrals.cpp.

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double CheMPS2::DMRGSCFintegrals::get_coulomb	(	const int	Ic1,
		const int	Ic2,
		const int	Ia1,
		const int	Ia2,
		const int	c1,
		const int	c2,
		const int	a1,
		const int	a2
	)		const

Get an element of the Coulomb object ( c1 c2 | a1 a2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Ia1	The irrep of the first core+virtual index
Ia2	The irrep of the second core+virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
a1	The first core+virtual index (within the irrep block)
a2	The second core+virtual index (within the irrep block)

Returns: The desired value of the Coulomb object

Definition at line 194 of file DMRGSCFintegrals.cpp.

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double CheMPS2::DMRGSCFintegrals::get_exchange	(	const int	Ic1,
		const int	Ic2,
		const int	Iv1,
		const int	Iv2,
		const int	c1,
		const int	c2,
		const int	v1,
		const int	v2
	)		const

Get an element of the Exchange object ( c1 v1 | c2 v2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Iv1	The irrep of the first virtual index
Iv2	The irrep of the second virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
v1	The first virtual index (within the irrep block; counting starts at NCORE[ Iv1 ])
v2	The second virtual index (within the irrep block; counting starts at NCORE[ Iv2 ])

Returns: The desired value of the Exchange object

Definition at line 239 of file DMRGSCFintegrals.cpp.

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void CheMPS2::DMRGSCFintegrals::set_coulomb	(	const int	Ic1,
		const int	Ic2,
		const int	Ia1,
		const int	Ia2,
		const int	c1,
		const int	c2,
		const int	a1,
		const int	a2,
		const double	val
	)

Set an element of the Coulomb object ( c1 c2 | a1 a2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Ia1	The irrep of the first core+virtual index
Ia2	The irrep of the second core+virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
a1	The first core+virtual index (within the irrep block)
a2	The second core+virtual index (within the irrep block)
val	The value to which the element of the object should be set

Definition at line 182 of file DMRGSCFintegrals.cpp.

void CheMPS2::DMRGSCFintegrals::set_exchange	(	const int	Ic1,
		const int	Ic2,
		const int	Iv1,
		const int	Iv2,
		const int	c1,
		const int	c2,
		const int	v1,
		const int	v2,
		const double	val
	)

Set an element of the Exchange object ( c1 v1 | c2 v2 )

Parameters

Ic1	The irrep of the first core index
Ic2	The irrep of the second core index
Iv1	The irrep of the first virtual index
Iv2	The irrep of the second virtual index
c1	The first core index (within the irrep block)
c2	The second core index (within the irrep block)
v1	The first virtual index (within the irrep block; counting starts at NCORE[ Iv1 ])
v2	The second virtual index (within the irrep block; counting starts at NCORE[ Iv2 ])
val	The value to which the element of the object should be set

Definition at line 227 of file DMRGSCFintegrals.cpp.

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

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation