GAS_doubles_PCHB_init Subroutine

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

@brief Initialize the pchb excitation generator

@details This does two things: 1. setup the lookup table for the mapping ab -> (a,b) 2. setup the alias table for picking ab given ij with probability ~

Type Bound

GAS_PCHB_DoublesSpinorbFullyWeightedExcGenerator_t

Arguments

Type IntentOptional Attributes Name
class(GAS_PCHB_DoublesSpinorbFullyWeightedExcGenerator_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

Contents

Source Code

GAS_doubles_PCHB_init

Source Code

    subroutine GAS_doubles_PCHB_init(this, GAS_spec, &
            use_lookup, create_lookup, PCHB_particle_selection)
        class(GAS_PCHB_DoublesSpinorbFullyWeightedExcGenerator_t), intent(inout) :: this
        class(GASSpec_t), intent(in) :: GAS_spec
        logical, intent(in) :: use_lookup, create_lookup
        type(PCHB_ParticleSelection_t), intent(in) :: PCHB_particle_selection
        character(*), parameter :: this_routine = 'GAS_doubles_PCHB_init'

        this%GAS_spec = GAS_spec
        allocate(this%indexer, source=SuperGroupIndexer_t(GAS_spec, nEl))
        this%create_lookup = create_lookup
        this%use_lookup = use_lookup

        if (this%create_lookup) then
            if (associated(lookup_supergroup_indexer)) then
                call stop_all(this_routine, 'Someone else is already managing the supergroup lookup.')
            else
                write(stdout, *) 'GAS PCHB (RHF) doubles is creating and managing the supergroup lookup'
                lookup_supergroup_indexer => this%indexer
            end if
        end if
        if (this%use_lookup) write(stdout, *) 'GAS PCHB doubles is using the supergroup lookup'

        this%last_possible_occupied = 0_n_int
        block
            integer :: i
            do i = 0, ilut_off(nBasis)
                this%last_possible_occupied = ibset(this%last_possible_occupied, i)
            end do
        end block

        call this%compute_samplers(PCHB_particle_selection)

        write(stdout, *) "Finished excitation generator initialization"
    end subroutine GAS_doubles_PCHB_init