gasci_pchb_doubles_spinorb_fastweighted Module

spin-orbital-resolved GASCI-PCHB using the “fast weighted” scheme


Uses


Contents

Derived Types

Functions

Subroutines


Derived Types

type, public, extends(DoubleExcitationGenerator_t) ::  GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t

GAS PCHB excitation generator for doubles using spin orbitals, with “fast weighting” This means we choose holes via

Components

Type Visibility Attributes Name Initial
logical, public :: use_lookup = .false.

use a lookup for the supergroup index
logical, public :: create_lookup = .false.

create and manage the supergroup index
class(ParticleSelector_t), private, allocatable :: particle_selector

particle selector for getting I, J
type(AliasSampler_2D_t), private :: AB_sampler

sampler for holes, dubbed (fused index) It yields where IJ is a fused index I < J and i_sg is the supergroup.
type(SuperGroupIndexer_t), private, pointer :: indexer => null()
class(GASSpec_t), private, allocatable :: GAS_spec
integer, private, allocatable :: tgtOrbs(:,:)

Type-Bound Procedures

procedure , public :: init => GAS_doubles_PCHB_spinorb_init Subroutine
procedure , public :: finalize => GAS_doubles_PCHB_spinorb_finalize Subroutine
procedure , public :: gen_exc => GAS_doubles_PCHB_spinorb_gen_exc Subroutine
procedure , public :: get_pgen => GAS_doubles_PCHB_spinorb_get_pgen Function
procedure , public :: gen_all_excits => GAS_doubles_PCHB_spinorb_gen_all_excits Subroutine
procedure , private , :: compute_samplers => GAS_doubles_PCHB_spinorb_compute_samplers Subroutine

Functions

private function GAS_doubles_PCHB_spinorb_get_pgen(this, nI, ilutI, ex, ic, ClassCount2, ClassCountUnocc2) result(pgen)

calculates the probability of drawing a given double excitation parametrised by the excitation matrix ex

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(inout) :: this
integer, intent(in) :: nI(nel)
integer(kind=n_int), intent(in) :: ilutI(0:NIfTot)
integer, intent(in) :: ex(2,maxExcit)

excitation matrix
integer, intent(in) :: ic

excitation matrix
integer, intent(in) :: ClassCount2(ScratchSize)
integer, intent(in) :: ClassCountUnocc2(ScratchSize)

Return Value real(kind=dp)


Subroutines

private subroutine GAS_doubles_PCHB_spinorb_init(this, GAS_spec, use_lookup, create_lookup, PCHB_particle_selection)

initalises the spinorb-resolved PCHB doubles excitation generator

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Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(inout) :: this
class(GASSpec_t), intent(in) :: GAS_spec
logical, intent(in) :: use_lookup
logical, intent(in) :: create_lookup
type(PCHB_ParticleSelection_t), intent(in) :: PCHB_particle_selection

private subroutine GAS_doubles_PCHB_spinorb_finalize(this)

deallocates the sampler and mapper

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(inout) :: this

private subroutine GAS_doubles_PCHB_spinorb_gen_exc(this, nI, ilutI, nJ, ilutJ, exFlag, ic, ex, tParity, pGen, hel, store, part_type)

given the initial determinant (both as nI and ilut), create a random doubles excitation using the Hamiltonian matrix elements as weights

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(inout) :: this

the exctitation generator
integer, intent(in) :: nI(nel)

determinant to excite from unused in this generator
integer(kind=n_int), intent(in) :: ilutI(0:NIfTot)

determint from which to excite, ilut format
integer, intent(out) :: nJ(nel)

the excited determinant upon return excitation order (for doubles generator, always == 2) excitation matrix nI -> nJ
integer(kind=n_int), intent(out) :: ilutJ(0:NifTot)

excited determinant, ilut format
integer, intent(in) :: exFlag

determinant to excite from unused in this generator
integer, intent(out) :: ic

the excited determinant upon return excitation order (for doubles generator, always == 2) excitation matrix nI -> nJ
integer, intent(out) :: ex(2,maxExcit)

the excited determinant upon return excitation order (for doubles generator, always == 2) excitation matrix nI -> nJ
logical, intent(out) :: tParity

the parity of the excitation nI -> nJ
real(kind=dp), intent(out) :: pGen

probability of generating the excitation
real(kind=dp), intent(out) :: hel

matrix element Hijab
type(excit_gen_store_type), intent(inout), target :: store
integer, intent(in), optional :: part_type

unused in this generator

private subroutine GAS_doubles_PCHB_spinorb_gen_all_excits(this, nI, n_excits, det_list)

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(in) :: this
integer, intent(in) :: nI(nEl)
integer, intent(out) :: n_excits
integer(kind=n_int), intent(out), allocatable :: det_list(:,:)

private subroutine GAS_doubles_PCHB_spinorb_compute_samplers(this, nBI, PCHB_particle_selection)

computes and stores values for the alias (spin-independent) sampling table

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinOrbFastWeightedExcGenerator_t), intent(inout) :: this
integer, intent(in) :: nBI
type(PCHB_ParticleSelection_t), intent(in) :: PCHB_particle_selection