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qp2/src/determinants/slater_rules.irp.f

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70 KiB
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subroutine get_excitation_degree(key1,key2,degree,Nint)
use bitmasks
include 'utils/constants.include.F'
implicit none
BEGIN_DOC
! Returns the excitation degree between two determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key1(Nint*2)
integer(bit_kind), intent(in) :: key2(Nint*2)
integer, intent(out) :: degree
integer(bit_kind) :: xorvec(2*N_int_max)
integer :: l
ASSERT (Nint > 0)
select case (Nint)
case (1)
xorvec(1) = xor( key1(1), key2(1))
xorvec(2) = xor( key1(2), key2(2))
degree = popcnt(xorvec(1))+popcnt(xorvec(2))
case (2)
xorvec(1) = xor( key1(1), key2(1))
xorvec(2) = xor( key1(2), key2(2))
xorvec(3) = xor( key1(3), key2(3))
xorvec(4) = xor( key1(4), key2(4))
degree = sum(popcnt(xorvec(1:4)))
case (3)
do l=1,6
xorvec(l) = xor( key1(l), key2(l))
enddo
degree = sum(popcnt(xorvec(1:6)))
case (4)
do l=1,8
xorvec(l) = xor( key1(l), key2(l))
enddo
degree = sum(popcnt(xorvec(1:8)))
case default
integer :: lmax
lmax = shiftl(Nint,1)
do l=1,lmax
xorvec(l) = xor( key1(l), key2(l))
enddo
degree = sum(popcnt(xorvec(1:lmax)))
end select
degree = shiftr(degree,1)
end
subroutine get_excitation(det1,det2,exc,degree,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the excitation operators between two determinants and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint,2)
integer(bit_kind), intent(in) :: det2(Nint,2)
integer, intent(out) :: exc(0:2,2,2)
integer, intent(out) :: degree
double precision, intent(out) :: phase
! exc(number,hole/particle,spin)
! ex :
! exc(0,1,1) = number of holes alpha
! exc(0,2,1) = number of particle alpha
! exc(0,2,2) = number of particle beta
! exc(1,2,1) = first particle alpha
! exc(1,1,1) = first hole alpha
! exc(1,2,2) = first particle beta
! exc(1,1,2) = first hole beta
! E_pq : T^alpha_pq + T^beta_pq
! T^alpha_pq : exc(0,1,1) = 1
! exc(0,2,1) = 1
! exc(1,1,1) = q
! exc(1,2,1) = p
! T^alpha_pq : exc(0,1,2) = 1
! exc(0,2,2) = 1
! exc(1,1,2) = q
! exc(1,2,2) = p
ASSERT (Nint > 0)
!DIR$ FORCEINLINE
call get_excitation_degree(det1,det2,degree,Nint)
select case (degree)
case (3:)
degree = -1
return
case (2)
call get_double_excitation(det1,det2,exc,phase,Nint)
return
case (1)
call get_single_excitation(det1,det2,exc,phase,Nint)
return
case(0)
return
end select
end
subroutine decode_exc(exc,degree,h1,p1,h2,p2,s1,s2)
use bitmasks
implicit none
BEGIN_DOC
! Decodes the exc arrays returned by get_excitation.
! h1,h2 : Holes
! p1,p2 : Particles
! s1,s2 : Spins (1:alpha, 2:beta)
! degree : Degree of excitation
END_DOC
integer, intent(in) :: exc(0:2,2,2),degree
integer, intent(out) :: h1,h2,p1,p2,s1,s2
ASSERT (degree > 0)
ASSERT (degree < 3)
select case(degree)
case(2)
if (exc(0,1,1) == 2) then
h1 = exc(1,1,1)
h2 = exc(2,1,1)
p1 = exc(1,2,1)
p2 = exc(2,2,1)
s1 = 1
s2 = 1
else if (exc(0,1,2) == 2) then
h1 = exc(1,1,2)
h2 = exc(2,1,2)
p1 = exc(1,2,2)
p2 = exc(2,2,2)
s1 = 2
s2 = 2
else
h1 = exc(1,1,1)
h2 = exc(1,1,2)
p1 = exc(1,2,1)
p2 = exc(1,2,2)
s1 = 1
s2 = 2
endif
case(1)
if (exc(0,1,1) == 1) then
h1 = exc(1,1,1)
h2 = 0
p1 = exc(1,2,1)
p2 = 0
s1 = 1
s2 = 0
else
h1 = exc(1,1,2)
h2 = 0
p1 = exc(1,2,2)
p2 = 0
s1 = 2
s2 = 0
endif
case(0)
h1 = 0
p1 = 0
h2 = 0
p2 = 0
s1 = 0
s2 = 0
end select
end
subroutine get_double_excitation(det1,det2,exc,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the two excitation operators between two doubly excited determinants and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint,2)
integer(bit_kind), intent(in) :: det2(Nint,2)
integer, intent(out) :: exc(0:2,2,2)
double precision, intent(out) :: phase
integer :: tz
integer :: l, ispin, idx_hole, idx_particle, ishift
integer :: nperm
integer :: i,j,k,m,n
integer :: high, low
integer :: a,b,c,d
integer(bit_kind) :: hole, particle, tmp
double precision, parameter :: phase_dble(0:1) = (/ 1.d0, -1.d0 /)
ASSERT (Nint > 0)
nperm = 0
exc(0,1,1) = 0
exc(0,2,1) = 0
exc(0,1,2) = 0
exc(0,2,2) = 0
do ispin = 1,2
idx_particle = 0
idx_hole = 0
ishift = 1-bit_kind_size
do l=1,Nint
ishift = ishift + bit_kind_size
if (det1(l,ispin) == det2(l,ispin)) then
cycle
endif
tmp = xor( det1(l,ispin), det2(l,ispin) )
particle = iand(tmp, det2(l,ispin))
hole = iand(tmp, det1(l,ispin))
do while (particle /= 0_bit_kind)
tz = trailz(particle)
idx_particle = idx_particle + 1
exc(0,2,ispin) = exc(0,2,ispin) + 1
exc(idx_particle,2,ispin) = tz+ishift
particle = iand(particle,particle-1_bit_kind)
enddo
if (iand(exc(0,1,ispin),exc(0,2,ispin))==2) then ! exc(0,1,ispin)==2 or exc(0,2,ispin)==2
exit
endif
do while (hole /= 0_bit_kind)
tz = trailz(hole)
idx_hole = idx_hole + 1
exc(0,1,ispin) = exc(0,1,ispin) + 1
exc(idx_hole,1,ispin) = tz+ishift
hole = iand(hole,hole-1_bit_kind)
enddo
if (iand(exc(0,1,ispin),exc(0,2,ispin))==2) then ! exc(0,1,ispin)==2 or exc(0,2,ispin)
exit
endif
enddo
select case (exc(0,1,ispin))
case(0)
cycle
case(1)
high = max(exc(1,1,ispin), exc(1,2,ispin))-1
low = min(exc(1,1,ispin), exc(1,2,ispin))
ASSERT (low >= 0)
ASSERT (high > 0)
k = shiftr(high,bit_kind_shift)+1
j = shiftr(low,bit_kind_shift)+1
m = iand(high,bit_kind_size-1)
n = iand(low,bit_kind_size-1)
if (j==k) then
nperm = nperm + popcnt(iand(det1(j,ispin), &
iand( shiftl(1_bit_kind,m)-1_bit_kind, &
not(shiftl(1_bit_kind,n))+1_bit_kind)) )
else
nperm = nperm + popcnt( &
iand(det1(j,ispin), &
iand(not(0_bit_kind), &
(not(shiftl(1_bit_kind,n)) + 1_bit_kind) ))) &
+ popcnt(iand(det1(k,ispin), &
(shiftl(1_bit_kind,m) - 1_bit_kind ) ))
do i=j+1,k-1
nperm = nperm + popcnt(det1(i,ispin))
end do
endif
case (2)
do l=1,2
high = max(exc(l,1,ispin), exc(l,2,ispin))-1
low = min(exc(l,1,ispin), exc(l,2,ispin))
ASSERT (low > 0)
ASSERT (high > 0)
k = shiftr(high,bit_kind_shift)+1
j = shiftr(low,bit_kind_shift)+1
m = iand(high,bit_kind_size-1)
n = iand(low,bit_kind_size-1)
if (j==k) then
nperm = nperm + popcnt(iand(det1(j,ispin), &
iand( shiftl(1_bit_kind,m)-1_bit_kind, &
not(shiftl(1_bit_kind,n))+1_bit_kind)) )
else
nperm = nperm + popcnt( &
iand(det1(j,ispin), &
iand(not(0_bit_kind), &
(not(shiftl(1_bit_kind,n)) + 1_bit_kind) ))) &
+ popcnt(iand(det1(k,ispin), &
(shiftl(1_bit_kind,m) - 1_bit_kind ) ))
do i=j+1,k-1
nperm = nperm + popcnt(det1(i,ispin))
end do
endif
enddo
a = min(exc(1,1,ispin), exc(1,2,ispin))
b = max(exc(1,1,ispin), exc(1,2,ispin))
c = min(exc(2,1,ispin), exc(2,2,ispin))
d = max(exc(2,1,ispin), exc(2,2,ispin))
if ((a<c) .and. (c<b) .and. (b<d)) then
nperm = nperm + 1
endif
exit
end select
enddo
phase = phase_dble(iand(nperm,1))
end
subroutine get_phasemask_bit(det1, pm, Nint)
use bitmasks
implicit none
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint,2)
integer(bit_kind), intent(out) :: pm(Nint,2)
integer(bit_kind) :: tmp
integer :: ispin, i
do ispin=1,2
tmp = 0_8
do i=1,Nint
pm(i,ispin) = xor(det1(i,ispin), shiftl(det1(i,ispin), 1))
pm(i,ispin) = xor(pm(i,ispin), shiftl(pm(i,ispin), 2))
pm(i,ispin) = xor(pm(i,ispin), shiftl(pm(i,ispin), 4))
pm(i,ispin) = xor(pm(i,ispin), shiftl(pm(i,ispin), 8))
pm(i,ispin) = xor(pm(i,ispin), shiftl(pm(i,ispin), 16))
pm(i,ispin) = xor(pm(i,ispin), shiftl(pm(i,ispin), 32))
pm(i,ispin) = xor(pm(i,ispin), tmp)
if(iand(popcnt(det1(i,ispin)), 1) == 1) tmp = not(tmp)
end do
end do
end
subroutine get_single_excitation(det1,det2,exc,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the excitation operator between two singly excited determinants and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint,2)
integer(bit_kind), intent(in) :: det2(Nint,2)
integer, intent(out) :: exc(0:2,2,2)
double precision, intent(out) :: phase
integer :: tz
integer :: l, ispin, idx_hole, idx_particle, ishift
integer :: nperm
integer :: i,j,k,m,n
integer :: high, low
integer :: a,b,c,d
integer(bit_kind) :: hole, particle, tmp
double precision, parameter :: phase_dble(0:1) = (/ 1.d0, -1.d0 /)
ASSERT (Nint > 0)
nperm = 0
exc(0,1,1) = 0
exc(0,2,1) = 0
exc(0,1,2) = 0
exc(0,2,2) = 0
do ispin = 1,2
ishift = 1-bit_kind_size
do l=1,Nint
ishift = ishift + bit_kind_size
if (det1(l,ispin) == det2(l,ispin)) then
cycle
endif
tmp = xor( det1(l,ispin), det2(l,ispin) )
particle = iand(tmp, det2(l,ispin))
hole = iand(tmp, det1(l,ispin))
if (particle /= 0_bit_kind) then
tz = trailz(particle)
exc(0,2,ispin) = 1
exc(1,2,ispin) = tz+ishift
endif
if (hole /= 0_bit_kind) then
tz = trailz(hole)
exc(0,1,ispin) = 1
exc(1,1,ispin) = tz+ishift
endif
if ( iand(exc(0,1,ispin),exc(0,2,ispin)) /= 1) then ! exc(0,1,ispin)/=1 and exc(0,2,ispin) /= 1
cycle
endif
high = max(exc(1,1,ispin), exc(1,2,ispin))-1
low = min(exc(1,1,ispin), exc(1,2,ispin))
ASSERT (low >= 0)
ASSERT (high > 0)
k = shiftr(high,bit_kind_shift)+1
j = shiftr(low,bit_kind_shift)+1
m = iand(high,bit_kind_size-1)
n = iand(low,bit_kind_size-1)
if (j==k) then
nperm = nperm + popcnt(iand(det1(j,ispin), &
iand( shiftl(1_bit_kind,m)-1_bit_kind, &
not(shiftl(1_bit_kind,n))+1_bit_kind)) )
else
nperm = nperm + popcnt( &
iand(det1(j,ispin), &
iand(not(0_bit_kind), &
(not(shiftl(1_bit_kind,n)) + 1_bit_kind) ))) &
+ popcnt(iand(det1(k,ispin), &
(shiftl(1_bit_kind,m) - 1_bit_kind ) ))
do i=j+1,k-1
nperm = nperm + popcnt(det1(i,ispin))
end do
endif
phase = phase_dble(iand(nperm,1))
return
enddo
enddo
end
subroutine bitstring_to_list_ab( string, list, n_elements, Nint)
use bitmasks
implicit none
BEGIN_DOC
! Gives the indices(+1) of the bits set to 1 in the bit string
! For alpha/beta determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: string(Nint,2)
integer, intent(out) :: list(Nint*bit_kind_size,2)
integer, intent(out) :: n_elements(2)
integer :: i, j, ishift
integer(bit_kind) :: l
n_elements(1) = 0
n_elements(2) = 0
ishift = 1
do i=1,Nint
l = string(i,1)
do while (l /= 0_bit_kind)
j = trailz(l)
n_elements(1) = n_elements(1)+1
l = ibclr(l,j)
list(n_elements(1),1) = ishift+j
enddo
l = string(i,2)
do while (l /= 0_bit_kind)
j = trailz(l)
n_elements(2) = n_elements(2)+1
l = ibclr(l,j)
list(n_elements(2),2) = ishift+j
enddo
ishift = ishift + bit_kind_size
enddo
end
!subroutine bitstring_to_list( string, list, n_elements, Nint)
! use bitmasks
! implicit none
! BEGIN_DOC
! ! Gives the indices(+1) of the bits set to 1 in the bit string
! END_DOC
! integer, intent(in) :: Nint
! integer(bit_kind), intent(in) :: string(Nint)
! integer, intent(out) :: list(Nint*bit_kind_size)
! integer, intent(out) :: n_elements
!
! integer :: i, j, ishift
! integer(bit_kind) :: l
!
! n_elements = 0
! ishift = 1
! do i=1,Nint
! l = string(i)
! do while (l /= 0_bit_kind)
! j = trailz(l)
! n_elements = n_elements + 1
! l = ibclr(l,j)
! list(n_elements) = ishift+j
! enddo
! ishift = ishift + bit_kind_size
! enddo
!
!end
subroutine i_H_j_s2(key_i,key_j,Nint,hij,s2)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ and $\langle i|S^2|j \rangle$
! where $i$ and $j$ are determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2), key_j(Nint,2)
double precision, intent(out) :: hij, s2
integer :: exc(0:2,2,2)
integer :: degree
double precision :: get_two_e_integral
integer :: m,n,p,q
integer :: i,j,k
integer :: occ(Nint*bit_kind_size,2)
double precision :: diag_H_mat_elem, phase
integer :: n_occ_ab(2)
PROVIDE mo_two_e_integrals_in_map mo_integrals_map big_array_exchange_integrals
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
ASSERT (sum(popcnt(key_i(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_i(:,2))) == elec_beta_num)
ASSERT (sum(popcnt(key_j(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_j(:,2))) == elec_beta_num)
hij = 0.d0
s2 = 0d0
!DIR$ FORCEINLINE
call get_excitation_degree(key_i,key_j,degree,Nint)
integer :: spin
select case (degree)
case (2)
call get_double_excitation(key_i,key_j,exc,phase,Nint)
! Single alpha, single beta
if (exc(0,1,1) == 1) then
if ( (exc(1,1,1) == exc(1,2,2)).and.(exc(1,1,2) == exc(1,2,1)) ) then
s2 = -phase
endif
if(exc(1,1,1) == exc(1,2,2) )then
hij = phase * big_array_exchange_integrals(exc(1,1,1),exc(1,1,2),exc(1,2,1))
else if (exc(1,2,1) ==exc(1,1,2))then
hij = phase * big_array_exchange_integrals(exc(1,2,1),exc(1,1,1),exc(1,2,2))
else
hij = phase*get_two_e_integral( &
exc(1,1,1), &
exc(1,1,2), &
exc(1,2,1), &
exc(1,2,2) ,mo_integrals_map)
endif
! Double alpha
else if (exc(0,1,1) == 2) then
hij = phase*(get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(1,2,1), &
exc(2,2,1) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(2,2,1), &
exc(1,2,1) ,mo_integrals_map) )
! Double beta
else if (exc(0,1,2) == 2) then
hij = phase*(get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(1,2,2), &
exc(2,2,2) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(2,2,2), &
exc(1,2,2) ,mo_integrals_map) )
endif
case (1)
call get_single_excitation(key_i,key_j,exc,phase,Nint)
!DIR$ FORCEINLINE
call bitstring_to_list_ab(key_i, occ, n_occ_ab, Nint)
! Single alpha
if (exc(0,1,1) == 1) then
m = exc(1,1,1)
p = exc(1,2,1)
spin = 1
! Single beta
else
m = exc(1,1,2)
p = exc(1,2,2)
spin = 2
endif
call get_single_excitation_from_fock(key_i,key_j,p,m,spin,phase,hij)
case (0)
double precision, external :: diag_S_mat_elem
s2 = diag_S_mat_elem(key_i,Nint)
hij = diag_H_mat_elem(key_i,Nint)
end select
end
subroutine i_H_j(key_i,key_j,Nint,hij)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ where $i$ and $j$ are determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2), key_j(Nint,2)
double precision, intent(out) :: hij
integer :: exc(0:2,2,2)
integer :: degree
double precision :: get_two_e_integral
integer :: m,n,p,q
integer :: i,j,k
integer :: occ(Nint*bit_kind_size,2)
double precision :: diag_H_mat_elem, phase
integer :: n_occ_ab(2)
PROVIDE mo_two_e_integrals_in_map mo_integrals_map big_array_exchange_integrals
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
ASSERT (sum(popcnt(key_i(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_i(:,2))) == elec_beta_num)
ASSERT (sum(popcnt(key_j(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_j(:,2))) == elec_beta_num)
hij = 0.d0
!DIR$ FORCEINLINE
call get_excitation_degree(key_i,key_j,degree,Nint)
integer :: spin
select case (degree)
case (2)
call get_double_excitation(key_i,key_j,exc,phase,Nint)
if (exc(0,1,1) == 1) then
! Single alpha, single beta
if(exc(1,1,1) == exc(1,2,2) )then
hij = phase * big_array_exchange_integrals(exc(1,1,1),exc(1,1,2),exc(1,2,1))
else if (exc(1,2,1) ==exc(1,1,2))then
hij = phase * big_array_exchange_integrals(exc(1,2,1),exc(1,1,1),exc(1,2,2))
else
hij = phase*get_two_e_integral( &
exc(1,1,1), &
exc(1,1,2), &
exc(1,2,1), &
exc(1,2,2) ,mo_integrals_map)
endif
else if (exc(0,1,1) == 2) then
! Double alpha
hij = phase*(get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(1,2,1), &
exc(2,2,1) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(2,2,1), &
exc(1,2,1) ,mo_integrals_map) )
else if (exc(0,1,2) == 2) then
! Double beta
hij = phase*(get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(1,2,2), &
exc(2,2,2) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(2,2,2), &
exc(1,2,2) ,mo_integrals_map) )
endif
case (1)
call get_single_excitation(key_i,key_j,exc,phase,Nint)
!DIR$ FORCEINLINE
call bitstring_to_list_ab(key_i, occ, n_occ_ab, Nint)
if (exc(0,1,1) == 1) then
! Single alpha
m = exc(1,1,1)
p = exc(1,2,1)
spin = 1
else
! Single beta
m = exc(1,1,2)
p = exc(1,2,2)
spin = 2
endif
call get_single_excitation_from_fock(key_i,key_j,p,m,spin,phase,hij)
case (0)
hij = diag_H_mat_elem(key_i,Nint)
end select
end
subroutine i_H_j_verbose(key_i,key_j,Nint,hij,hmono,hdouble,phase)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ where $i$ and $j$ are determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2), key_j(Nint,2)
double precision, intent(out) :: hij,hmono,hdouble,phase
integer :: exc(0:2,2,2)
integer :: degree
double precision :: get_two_e_integral
integer :: m,n,p,q
integer :: i,j,k
integer :: occ(Nint*bit_kind_size,2)
double precision :: diag_H_mat_elem
integer :: n_occ_ab(2)
logical :: has_mipi(Nint*bit_kind_size)
double precision :: mipi(Nint*bit_kind_size), miip(Nint*bit_kind_size)
PROVIDE mo_two_e_integrals_in_map mo_integrals_map
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
ASSERT (sum(popcnt(key_i(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_i(:,2))) == elec_beta_num)
ASSERT (sum(popcnt(key_j(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(key_j(:,2))) == elec_beta_num)
hij = 0.d0
hmono = 0.d0
hdouble = 0.d0
!DIR$ FORCEINLINE
call get_excitation_degree(key_i,key_j,degree,Nint)
select case (degree)
case (2)
call get_double_excitation(key_i,key_j,exc,phase,Nint)
if (exc(0,1,1) == 1) then
! Single alpha, single beta
hij = phase*get_two_e_integral( &
exc(1,1,1), &
exc(1,1,2), &
exc(1,2,1), &
exc(1,2,2) ,mo_integrals_map)
else if (exc(0,1,1) == 2) then
! Double alpha
hij = phase*(get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(1,2,1), &
exc(2,2,1) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,1), &
exc(2,1,1), &
exc(2,2,1), &
exc(1,2,1) ,mo_integrals_map) )
else if (exc(0,1,2) == 2) then
! Double beta
hij = phase*(get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(1,2,2), &
exc(2,2,2) ,mo_integrals_map) - &
get_two_e_integral( &
exc(1,1,2), &
exc(2,1,2), &
exc(2,2,2), &
exc(1,2,2) ,mo_integrals_map) )
endif
case (1)
call get_single_excitation(key_i,key_j,exc,phase,Nint)
!DIR$ FORCEINLINE
call bitstring_to_list_ab(key_i, occ, n_occ_ab, Nint)
has_mipi = .False.
if (exc(0,1,1) == 1) then
! Single alpha
m = exc(1,1,1)
p = exc(1,2,1)
do k = 1, elec_alpha_num
i = occ(k,1)
if (.not.has_mipi(i)) then
mipi(i) = get_two_e_integral(m,i,p,i,mo_integrals_map)
miip(i) = get_two_e_integral(m,i,i,p,mo_integrals_map)
has_mipi(i) = .True.
endif
enddo
do k = 1, elec_beta_num
i = occ(k,2)
if (.not.has_mipi(i)) then
mipi(i) = get_two_e_integral(m,i,p,i,mo_integrals_map)
has_mipi(i) = .True.
endif
enddo
do k = 1, elec_alpha_num
hdouble = hdouble + mipi(occ(k,1)) - miip(occ(k,1))
enddo
do k = 1, elec_beta_num
hdouble = hdouble + mipi(occ(k,2))
enddo
else
! Single beta
m = exc(1,1,2)
p = exc(1,2,2)
do k = 1, elec_beta_num
i = occ(k,2)
if (.not.has_mipi(i)) then
mipi(i) = get_two_e_integral(m,i,p,i,mo_integrals_map)
miip(i) = get_two_e_integral(m,i,i,p,mo_integrals_map)
has_mipi(i) = .True.
endif
enddo
do k = 1, elec_alpha_num
i = occ(k,1)
if (.not.has_mipi(i)) then
mipi(i) = get_two_e_integral(m,i,p,i,mo_integrals_map)
has_mipi(i) = .True.
endif
enddo
do k = 1, elec_alpha_num
hdouble = hdouble + mipi(occ(k,1))
enddo
do k = 1, elec_beta_num
hdouble = hdouble + mipi(occ(k,2)) - miip(occ(k,2))
enddo
endif
hmono = mo_one_e_integrals(m,p)
hij = phase*(hdouble + hmono)
case (0)
phase = 1.d0
hij = diag_H_mat_elem(key_i,Nint)
end select
end
subroutine create_minilist(key_mask, fullList, miniList, idx_miniList, N_fullList, N_miniList, Nint)
use bitmasks
implicit none
integer, intent(in) :: N_fullList
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: fullList(Nint, 2, N_fullList)
integer(bit_kind),intent(out) :: miniList(Nint, 2, N_fullList)
integer,intent(out) :: idx_miniList(N_fullList), N_miniList
integer(bit_kind) :: key_mask(Nint, 2)
integer :: ni, k, i, n_a, n_b, e_a, e_b
n_a = popcnt(key_mask(1,1))
n_b = popcnt(key_mask(1,2))
do ni=2,nint
n_a = n_a + popcnt(key_mask(ni,1))
n_b = n_b + popcnt(key_mask(ni,2))
end do
if(n_a == 0) then
N_miniList = N_fullList
do k=1,N_fullList
do ni=1,Nint
miniList(ni,1,k) = fullList(ni,1,k)
miniList(ni,2,k) = fullList(ni,2,k)
enddo
enddo
do i=1,N_fullList
idx_miniList(i) = i
end do
return
end if
N_miniList = 0
integer :: e_ab
e_ab = n_a+n_b
do i=1,N_fullList
e_a = e_ab - popcnt(iand(fullList(1, 1, i), key_mask(1, 1))) &
- popcnt(iand(fullList(1, 2, i), key_mask(1, 2)))
do ni=2,nint
e_a = e_a - popcnt(iand(fullList(ni, 1, i), key_mask(ni, 1))) &
- popcnt(iand(fullList(ni, 2, i), key_mask(ni, 2)))
end do
if(e_a > 2) then
cycle
endif
N_miniList = N_miniList + 1
miniList(1,1,N_miniList) = fullList(1,1,i)
miniList(1,2,N_miniList) = fullList(1,2,i)
do ni=2,Nint
miniList(ni,1,N_miniList) = fullList(ni,1,i)
miniList(ni,2,N_miniList) = fullList(ni,2,i)
enddo
idx_miniList(N_miniList) = i
end do
end subroutine
subroutine create_minilist_find_previous(key_mask, fullList, miniList, N_fullList, N_miniList, fullMatch, Nint)
use bitmasks
implicit none
integer, intent(in) :: N_fullList
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: fullList(Nint, 2, N_fullList)
integer(bit_kind),intent(out) :: miniList(Nint, 2, N_fullList)
integer(bit_kind), allocatable :: subList(:,:,:)
logical,intent(out) :: fullMatch
integer,intent(out) :: N_miniList
integer(bit_kind) :: key_mask(Nint, 2)
integer :: ni, i, k, l, N_subList
allocate (subList(Nint, 2, N_fullList))
fullMatch = .false.
N_miniList = 0
N_subList = 0
l = popcnt(key_mask(1,1)) + popcnt(key_mask(1,2))
do ni = 2,Nint
l = l + popcnt(key_mask(ni,1)) + popcnt(key_mask(ni,2))
end do
if(l == 0) then
N_miniList = N_fullList
do k=1,N_fullList
do ni=1,Nint
miniList(ni,1,k) = fullList(ni,1,k)
miniList(ni,2,k) = fullList(ni,2,k)
enddo
enddo
else
do i=N_fullList,1,-1
k = l
do ni=1,nint
k -= popcnt(iand(key_mask(ni,1), fullList(ni,1,i))) + popcnt(iand(key_mask(ni,2), fullList(ni,2,i)))
end do
if(k == 2) then
N_subList += 1
do ni=1,Nint
subList(ni,1,N_subList) = fullList(ni,1,i)
subList(ni,2,N_subList) = fullList(ni,2,i)
enddo
else if(k == 1) then
N_minilist += 1
do ni=1,Nint
miniList(ni,1,N_minilist) = fullList(ni,1,i)
miniList(ni,2,N_minilist) = fullList(ni,2,i)
enddo
else if(k == 0) then
N_minilist += 1
do ni=1,Nint
miniList(ni,1,N_minilist) = fullList(ni,1,i)
miniList(ni,2,N_minilist) = fullList(ni,2,i)
enddo
! fullMatch = .true.
! return
end if
end do
end if
if(N_subList > 0) then
do k=1,N_subList
do ni=1,Nint
miniList(ni,1,N_minilist+k) = sublist(ni,1,k)
miniList(ni,2,N_minilist+k) = sublist(ni,2,k)
enddo
enddo
N_minilist = N_minilist + N_subList
end if
deallocate(sublist)
end subroutine
subroutine i_H_psi(key,keys,coef,Nint,Ndet,Ndet_max,Nstate,i_H_psi_array)
use bitmasks
implicit none
BEGIN_DOC
! Computes $\langle i|H|Psi \rangle = \sum_J c_J \langle i | H | J \rangle$.
!
! Uses filter_connected_i_H_psi0 to get all the $|J \rangle$ to which $|i \rangle$
! is connected.
! The i_H_psi_minilist is much faster but requires to build the
! minilists.
END_DOC
integer, intent(in) :: Nint, Ndet,Ndet_max,Nstate
integer(bit_kind), intent(in) :: keys(Nint,2,Ndet)
integer(bit_kind), intent(in) :: key(Nint,2)
double precision, intent(in) :: coef(Ndet_max,Nstate)
double precision, intent(out) :: i_H_psi_array(Nstate)
integer :: i, ii,j
double precision :: phase
integer :: exc(0:2,2,2)
double precision :: hij
integer, allocatable :: idx(:)
ASSERT (Nint > 0)
ASSERT (N_int == Nint)
ASSERT (Nstate > 0)
ASSERT (Ndet > 0)
ASSERT (Ndet_max >= Ndet)
allocate(idx(0:Ndet))
i_H_psi_array = 0.d0
call filter_connected_i_H_psi0(keys,key,Nint,Ndet,idx)
if (Nstate == 1) then
do ii=1,idx(0)
i = idx(ii)
!DIR$ FORCEINLINE
call i_H_j(keys(1,1,i),key,Nint,hij)
i_H_psi_array(1) = i_H_psi_array(1) + coef(i,1)*hij
enddo
else
do ii=1,idx(0)
i = idx(ii)
!DIR$ FORCEINLINE
call i_H_j(keys(1,1,i),key,Nint,hij)
do j = 1, Nstate
i_H_psi_array(j) = i_H_psi_array(j) + coef(i,j)*hij
enddo
enddo
endif
end
subroutine i_H_psi_minilist(key,keys,idx_key,N_minilist,coef,Nint,Ndet,Ndet_max,Nstate,i_H_psi_array)
use bitmasks
implicit none
integer, intent(in) :: Nint, Ndet,Ndet_max,Nstate,idx_key(Ndet), N_minilist
integer(bit_kind), intent(in) :: keys(Nint,2,Ndet)
integer(bit_kind), intent(in) :: key(Nint,2)
double precision, intent(in) :: coef(Ndet_max,Nstate)
double precision, intent(out) :: i_H_psi_array(Nstate)
integer :: i, ii,j, i_in_key, i_in_coef
double precision :: phase
integer :: exc(0:2,2,2)
double precision :: hij
integer, allocatable :: idx(:)
BEGIN_DOC
! Computes $\langle i|H|\Psi \rangle = \sum_J c_J \langle i|H|J\rangle$.
!
! Uses filter_connected_i_H_psi0 to get all the $|J \rangle$ to which $|i \rangle$
! is connected. The $|J\rangle$ are searched in short pre-computed lists.
END_DOC
ASSERT (Nint > 0)
ASSERT (N_int == Nint)
ASSERT (Nstate > 0)
ASSERT (Ndet > 0)
ASSERT (Ndet_max >= Ndet)
allocate(idx(0:Ndet))
i_H_psi_array = 0.d0
call filter_connected_i_H_psi0(keys,key,Nint,N_minilist,idx)
if (Nstate == 1) then
do ii=1,idx(0)
i_in_key = idx(ii)
i_in_coef = idx_key(idx(ii))
!DIR$ FORCEINLINE
call i_H_j(keys(1,1,i_in_key),key,Nint,hij)
! TODO : Cache misses
i_H_psi_array(1) = i_H_psi_array(1) + coef(i_in_coef,1)*hij
enddo
else
do ii=1,idx(0)
i_in_key = idx(ii)
i_in_coef = idx_key(idx(ii))
!DIR$ FORCEINLINE
call i_H_j(keys(1,1,i_in_key),key,Nint,hij)
do j = 1, Nstate
i_H_psi_array(j) = i_H_psi_array(j) + coef(i_in_coef,j)*hij
enddo
enddo
endif
end
subroutine get_excitation_degree_vector_single(key1,key2,degree,Nint,sze,idx)
use bitmasks
implicit none
BEGIN_DOC
! Applies get_excitation_degree to an array of determinants and returns only
! the single excitations.
END_DOC
integer, intent(in) :: Nint, sze
integer(bit_kind), intent(in) :: key1(Nint,2,sze)
integer(bit_kind), intent(in) :: key2(Nint,2)
integer, intent(out) :: degree(sze)
integer, intent(out) :: idx(0:sze)
integer :: i,l,d,m
ASSERT (Nint > 0)
ASSERT (sze > 0)
l=1
if (Nint==1) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2)))
if (d > 2) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==2) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2)))
if (d > 2) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==3) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2))) + &
popcnt(xor( key1(3,1,i), key2(3,1))) + &
popcnt(xor( key1(3,2,i), key2(3,2)))
if (d > 2) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = 0
!DIR$ LOOP COUNT MIN(4)
do m=1,Nint
d = d + popcnt(xor( key1(m,1,i), key2(m,1))) &
+ popcnt(xor( key1(m,2,i), key2(m,2)))
enddo
if (d > 2) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
endif
idx(0) = l-1
end
subroutine get_excitation_degree_vector_single_or_exchange(key1,key2,degree,Nint,sze,idx)
use bitmasks
implicit none
BEGIN_DOC
! Applies get_excitation_degree to an array of determinants and return only the
! single excitations and the connections through exchange integrals.
END_DOC
integer, intent(in) :: Nint, sze
integer(bit_kind), intent(in) :: key1(Nint,2,sze)
integer(bit_kind), intent(in) :: key2(Nint,2)
integer, intent(out) :: degree(sze)
integer, intent(out) :: idx(0:sze)
integer(bit_kind) :: key_tmp(Nint,2)
integer :: i,l,d,m
integer :: exchange_1,exchange_2
ASSERT (Nint > 0)
ASSERT (sze > 0)
l=1
if (Nint==1) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2)))
key_tmp(1,1) = xor(key1(1,1,i),key2(1,1))
key_tmp(1,2) = xor(key1(1,2,i),key2(1,2))
if(popcnt(key_tmp(1,1)) .ge.3 .or. popcnt(key_tmp(1,2)) .ge.3 )cycle !! no double excitations of same spin
if (d > 4)cycle
if (d ==4)then
if(popcnt(xor(key_tmp(1,1),key_tmp(1,2))) == 0)then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else
cycle
endif
! pause
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else
print*, 'get_excitation_degree_vector_single_or_exchange not yet implemented for N_int > 1 ...'
stop
endif
idx(0) = l-1
end
subroutine get_excitation_degree_vector_double_alpha_beta(key1,key2,degree,Nint,sze,idx)
use bitmasks
implicit none
BEGIN_DOC
! Applies get_excitation_degree to an array of determinants and return only the
! single excitations and the connections through exchange integrals.
END_DOC
integer, intent(in) :: Nint, sze
integer(bit_kind), intent(in) :: key1(Nint,2,sze)
integer(bit_kind), intent(in) :: key2(Nint,2)
integer, intent(out) :: degree(sze)
integer, intent(out) :: idx(0:sze)
integer(bit_kind) :: key_tmp(Nint,2)
integer :: i,l,d,m
integer :: degree_alpha, degree_beta
ASSERT (Nint > 0)
ASSERT (sze > 0)
l=1
if (Nint==1) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2)))
if (d .ne.4)cycle
key_tmp(1,1) = xor(key1(1,1,i),key2(1,1))
key_tmp(1,2) = xor(key1(1,2,i),key2(1,2))
degree_alpha = popcnt(key_tmp(1,1))
degree_beta = popcnt(key_tmp(1,2))
if(degree_alpha .ge.3 .or. degree_beta .ge.3 )cycle !! no double excitations of same spin
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
enddo
else if (Nint==2) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2)))
if (d .ne.4)cycle
key_tmp(1,1) = xor(key1(1,1,i),key2(1,1))
key_tmp(1,2) = xor(key1(1,2,i),key2(1,2))
key_tmp(2,1) = xor(key1(2,1,i),key2(2,1))
key_tmp(2,2) = xor(key1(2,2,i),key2(2,2))
degree_alpha = popcnt(key_tmp(1,1)) + popcnt(key_tmp(2,1))
degree_beta = popcnt(key_tmp(1,2)) + popcnt(key_tmp(2,2))
if(degree_alpha .ge.3 .or. degree_beta .ge.3 )cycle !! no double excitations of same spin
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
enddo
else if (Nint==3) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2))) + &
popcnt(xor( key1(3,1,i), key2(3,1))) + &
popcnt(xor( key1(3,2,i), key2(3,2)))
if (d .ne.4)cycle
key_tmp(1,1) = xor(key1(1,1,i),key2(1,1))
key_tmp(1,2) = xor(key1(1,2,i),key2(1,2))
key_tmp(2,1) = xor(key1(2,1,i),key2(2,1))
key_tmp(2,2) = xor(key1(2,2,i),key2(2,2))
key_tmp(3,1) = xor(key1(3,1,i),key2(3,1))
key_tmp(3,2) = xor(key1(3,2,i),key2(3,2))
degree_alpha = popcnt(key_tmp(1,1)) + popcnt(key_tmp(2,1)) + popcnt(key_tmp(3,1))
degree_beta = popcnt(key_tmp(1,2)) + popcnt(key_tmp(2,2)) + popcnt(key_tmp(3,2))
if(degree_alpha .ge.3 .or. degree_beta .ge.3 )cycle !! no double excitations of same spin
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
enddo
else
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = 0
degree_alpha = 0
degree_beta = 0
!DIR$ LOOP COUNT MIN(4)
do m=1,Nint
d = d + popcnt(xor( key1(m,1,i), key2(m,1))) &
+ popcnt(xor( key1(m,2,i), key2(m,2)))
key_tmp(m,1) = xor(key1(m,1,i),key2(m,1))
key_tmp(m,2) = xor(key1(m,2,i),key2(m,2))
degree_alpha += popcnt(key_tmp(m,1))
degree_beta += popcnt(key_tmp(m,2))
enddo
if(degree_alpha .ge.3 .or. degree_beta .ge.3 )cycle !! no double excitations of same spin
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
enddo
endif
idx(0) = l-1
end
subroutine get_excitation_degree_vector_single_or_exchange_verbose(key1,key2,degree,Nint,sze,idx)
use bitmasks
implicit none
BEGIN_DOC
! Applies get_excitation_degree to an array of determinants and return only the single
! excitations and the connections through exchange integrals.
END_DOC
integer, intent(in) :: Nint, sze
integer(bit_kind), intent(in) :: key1(Nint,2,sze)
integer(bit_kind), intent(in) :: key2(Nint,2)
integer, intent(out) :: degree(sze)
integer, intent(out) :: idx(0:sze)
integer :: i,l,d,m
integer :: exchange_1,exchange_2
ASSERT (Nint > 0)
ASSERT (sze > 0)
l=1
if (Nint==1) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2)))
exchange_1 = popcnt(xor(ior(key1(1,1,i),key1(1,2,i)),ior(key2(1,1),key2(1,2))))
exchange_2 = popcnt(ior(xor(key1(1,1,i),key2(1,1)),xor(key1(1,2,i),key2(1,2))))
if(i==99)then
integer(bit_kind) :: key_test(N_int,2)
key_test(1,2) = 0_bit_kind
call debug_det(key2,N_int)
key_test(1,1) = ior(key2(1,1),key2(1,2))
call debug_det(key_test,N_int)
key_test(1,1) = ior(key1(1,1,i),key1(1,2,i))
call debug_det(key1(1,1,i),N_int)
call debug_det(key_test,N_int)
key_test(1,1) = xor(ior(key1(1,1,i),key1(1,2,i)),ior(key2(1,1),key2(1,2)))
call debug_det(key_test,N_int)
print*, exchange_1 , exchange_2
stop
endif
if (d > 4)cycle
if (d ==4)then
if(exchange_1 .eq. 0 ) then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else if (exchange_1 .eq. 2 .and. exchange_2.eq.2)then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else
cycle
endif
! pause
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==2) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2)))
exchange_1 = popcnt(xor(iand(key1(1,1,i),key1(1,2,i)),iand(key2(1,2),key2(1,2)))) + &
popcnt(xor(iand(key1(2,1,i),key1(2,2,i)),iand(key2(2,2),key2(2,2))))
exchange_2 = popcnt(iand(xor(key1(1,1,i),key2(1,1)),xor(key1(1,2,i),key2(1,2)))) + &
popcnt(iand(xor(key1(2,1,i),key2(2,1)),xor(key1(2,2,i),key2(2,2))))
if (d > 4)cycle
if (d ==4)then
if(exchange_1 .eq. 0 ) then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else if (exchange_1 .eq. 2 .and. exchange_2.eq.2)then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else
cycle
endif
! pause
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==3) then
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2))) + &
popcnt(xor( key1(3,1,i), key2(3,1))) + &
popcnt(xor( key1(3,2,i), key2(3,2)))
exchange_1 = popcnt(xor(iand(key1(1,1,i),key1(1,2,i)),iand(key2(1,1),key2(1,2)))) + &
popcnt(xor(iand(key1(2,1,i),key1(2,2,i)),iand(key2(2,1),key2(2,2)))) + &
popcnt(xor(iand(key1(3,1,i),key1(3,2,i)),iand(key2(3,1),key2(3,2))))
exchange_2 = popcnt(iand(xor(key1(1,1,i),key2(1,1)),xor(key1(1,2,i),key2(1,2)))) + &
popcnt(iand(xor(key1(2,1,i),key2(2,1)),xor(key1(2,2,i),key2(2,2)))) + &
popcnt(iand(xor(key1(3,1,i),key2(3,1)),xor(key1(3,2,i),key2(3,2))))
if (d > 4)cycle
if (d ==4)then
if(exchange_1 .eq. 0 ) then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else if (exchange_1 .eq. 2 .and. exchange_2.eq.2)then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else
cycle
endif
! pause
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else
!DIR$ LOOP COUNT (1000)
do i=1,sze
d = 0
exchange_1 = 0
exchange_2 = 0
!DIR$ LOOP COUNT MIN(4)
do m=1,Nint
d = d + popcnt(xor( key1(m,1,i), key2(m,1))) &
+ popcnt(xor( key1(m,2,i), key2(m,2)))
exchange_1 += popcnt(xor(iand(key1(m,1,i),key1(m,2,i)),iand(key2(m,1),key2(m,2))))
exchange_2 += popcnt(iand(xor(key1(m,1,i),key2(m,1)),xor(key1(m,2,i),key2(m,2))))
enddo
if (d > 4)cycle
if (d ==4)then
if(exchange_1 .eq. 0 ) then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else if (exchange_1 .eq. 2 .and. exchange_2.eq.2)then
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
else
cycle
endif
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
endif
idx(0) = l-1
end
subroutine get_excitation_degree_vector(key1,key2,degree,Nint,sze,idx)
use bitmasks
implicit none
BEGIN_DOC
! Applies get_excitation_degree to an array of determinants.
END_DOC
integer, intent(in) :: Nint, sze
integer(bit_kind), intent(in) :: key1(Nint,2,sze)
integer(bit_kind), intent(in) :: key2(Nint,2)
integer, intent(out) :: degree(sze)
integer, intent(out) :: idx(0:sze)
integer :: i,l,d,m
ASSERT (Nint > 0)
ASSERT (sze > 0)
l=1
if (Nint==1) then
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2)))
if (d > 4) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==2) then
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2)))
if (d > 4) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else if (Nint==3) then
do i=1,sze
d = popcnt(xor( key1(1,1,i), key2(1,1))) + &
popcnt(xor( key1(1,2,i), key2(1,2))) + &
popcnt(xor( key1(2,1,i), key2(2,1))) + &
popcnt(xor( key1(2,2,i), key2(2,2))) + &
popcnt(xor( key1(3,1,i), key2(3,1))) + &
popcnt(xor( key1(3,2,i), key2(3,2)))
if (d > 4) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
else
do i=1,sze
d = 0
do m=1,Nint
d = d + popcnt(xor( key1(m,1,i), key2(m,1))) &
+ popcnt(xor( key1(m,2,i), key2(m,2)))
enddo
if (d > 4) then
cycle
else
degree(l) = shiftr(d,1)
idx(l) = i
l = l+1
endif
enddo
endif
idx(0) = l-1
end
double precision function diag_H_mat_elem_fock(det_ref,det_pert,fock_diag_tmp,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Computes $\langle i|H|i \rangle$ when $i$ is at most a double excitation from
! a reference.
END_DOC
integer,intent(in) :: Nint
integer(bit_kind),intent(in) :: det_ref(Nint,2), det_pert(Nint,2)
double precision, intent(in) :: fock_diag_tmp(2,mo_num+1)
integer :: degree
double precision :: phase, E0
integer :: exc(0:2,2,2)
integer :: h1, p1, h2, p2, s1, s2
call get_excitation_degree(det_ref,det_pert,degree,Nint)
E0 = fock_diag_tmp(1,mo_num+1)
if (degree == 2) then
call get_double_excitation(det_ref,det_pert,exc,phase,Nint)
call decode_exc(exc,2,h1,p1,h2,p2,s1,s2)
if ( (s1 == 1).and.(s2 == 1) ) then ! alpha/alpha
diag_H_mat_elem_fock = E0 &
- fock_diag_tmp(1,h1) &
+ ( fock_diag_tmp(1,p1) - mo_two_e_integrals_jj_anti(h1,p1) ) &
- ( fock_diag_tmp(1,h2) - mo_two_e_integrals_jj_anti(h1,h2) &
+ mo_two_e_integrals_jj_anti(p1,h2) ) &
+ ( fock_diag_tmp(1,p2) - mo_two_e_integrals_jj_anti(h1,p2) &
+ mo_two_e_integrals_jj_anti(p1,p2) - mo_two_e_integrals_jj_anti(h2,p2) )
else if ( (s1 == 2).and.(s2 == 2) ) then ! beta/beta
diag_H_mat_elem_fock = E0 &
- fock_diag_tmp(2,h1) &
+ ( fock_diag_tmp(2,p1) - mo_two_e_integrals_jj_anti(h1,p1) ) &
- ( fock_diag_tmp(2,h2) - mo_two_e_integrals_jj_anti(h1,h2) &
+ mo_two_e_integrals_jj_anti(p1,h2) ) &
+ ( fock_diag_tmp(2,p2) - mo_two_e_integrals_jj_anti(h1,p2) &
+ mo_two_e_integrals_jj_anti(p1,p2) - mo_two_e_integrals_jj_anti(h2,p2) )
else ! alpha/beta
diag_H_mat_elem_fock = E0 &
- fock_diag_tmp(1,h1) &
+ ( fock_diag_tmp(1,p1) - mo_two_e_integrals_jj_anti(h1,p1) ) &
- ( fock_diag_tmp(2,h2) - mo_two_e_integrals_jj(h1,h2) &
+ mo_two_e_integrals_jj(p1,h2) ) &
+ ( fock_diag_tmp(2,p2) - mo_two_e_integrals_jj(h1,p2) &
+ mo_two_e_integrals_jj(p1,p2) - mo_two_e_integrals_jj_anti(h2,p2) )
endif
else if (degree == 1) then
call get_single_excitation(det_ref,det_pert,exc,phase,Nint)
call decode_exc(exc,1,h1,p1,h2,p2,s1,s2)
if (s1 == 1) then
diag_H_mat_elem_fock = E0 - fock_diag_tmp(1,h1) &
+ ( fock_diag_tmp(1,p1) - mo_two_e_integrals_jj_anti(h1,p1) )
else
diag_H_mat_elem_fock = E0 - fock_diag_tmp(2,h1) &
+ ( fock_diag_tmp(2,p1) - mo_two_e_integrals_jj_anti(h1,p1) )
endif
else if (degree == 0) then
diag_H_mat_elem_fock = E0
else
STOP 'Bug in diag_H_mat_elem_fock'
endif
end
double precision function diag_H_mat_elem(det_in,Nint)
implicit none
BEGIN_DOC
! Computes $\langle i|H|i \rangle$.
END_DOC
integer,intent(in) :: Nint
integer(bit_kind),intent(in) :: det_in(Nint,2)
integer(bit_kind) :: hole(Nint,2)
integer(bit_kind) :: particle(Nint,2)
integer :: i, nexc(2), ispin
integer :: occ_particle(Nint*bit_kind_size,2)
integer :: occ_hole(Nint*bit_kind_size,2)
integer(bit_kind) :: det_tmp(Nint,2)
integer :: na, nb
ASSERT (Nint > 0)
ASSERT (sum(popcnt(det_in(:,1))) == elec_alpha_num)
ASSERT (sum(popcnt(det_in(:,2))) == elec_beta_num)
nexc(1) = 0
nexc(2) = 0
do i=1,Nint
hole(i,1) = xor(det_in(i,1),ref_bitmask(i,1))
hole(i,2) = xor(det_in(i,2),ref_bitmask(i,2))
particle(i,1) = iand(hole(i,1),det_in(i,1))
particle(i,2) = iand(hole(i,2),det_in(i,2))
hole(i,1) = iand(hole(i,1),ref_bitmask(i,1))
hole(i,2) = iand(hole(i,2),ref_bitmask(i,2))
nexc(1) = nexc(1) + popcnt(hole(i,1))
nexc(2) = nexc(2) + popcnt(hole(i,2))
enddo
diag_H_mat_elem = ref_bitmask_energy
if (nexc(1)+nexc(2) == 0) then
return
endif
!call debug_det(det_in,Nint)
integer :: tmp(2)
!DIR$ FORCEINLINE
call bitstring_to_list_ab(particle, occ_particle, tmp, Nint)
ASSERT (tmp(1) == nexc(1))
ASSERT (tmp(2) == nexc(2))
!DIR$ FORCEINLINE
call bitstring_to_list_ab(hole, occ_hole, tmp, Nint)
ASSERT (tmp(1) == nexc(1))
ASSERT (tmp(2) == nexc(2))
det_tmp = ref_bitmask
do ispin=1,2
na = elec_num_tab(ispin)
nb = elec_num_tab(iand(ispin,1)+1)
do i=1,nexc(ispin)
!DIR$ FORCEINLINE
call ac_operator( occ_particle(i,ispin), ispin, det_tmp, diag_H_mat_elem, Nint,na,nb)
!DIR$ FORCEINLINE
call a_operator ( occ_hole (i,ispin), ispin, det_tmp, diag_H_mat_elem, Nint,na,nb)
enddo
enddo
end
subroutine a_operator(iorb,ispin,key,hjj,Nint,na,nb)
use bitmasks
implicit none
BEGIN_DOC
! Needed for :c:func:`diag_H_mat_elem`.
END_DOC
integer, intent(in) :: iorb, ispin, Nint
integer, intent(inout) :: na, nb
integer(bit_kind), intent(inout) :: key(Nint,2)
double precision, intent(inout) :: hjj
integer :: occ(Nint*bit_kind_size,2)
integer :: other_spin
integer :: k,l,i
integer :: tmp(2)
ASSERT (iorb > 0)
ASSERT (ispin > 0)
ASSERT (ispin < 3)
ASSERT (Nint > 0)
k = shiftr(iorb-1,bit_kind_shift)+1
ASSERT (k>0)
l = iorb - shiftl(k-1,bit_kind_shift)-1
key(k,ispin) = ibclr(key(k,ispin),l)
other_spin = iand(ispin,1)+1
!DIR$ FORCEINLINE
call bitstring_to_list_ab(key, occ, tmp, Nint)
na = na-1
hjj = hjj - mo_one_e_integrals(iorb,iorb)
! Same spin
do i=1,na
hjj = hjj - mo_two_e_integrals_jj_anti(occ(i,ispin),iorb)
enddo
! Opposite spin
do i=1,nb
hjj = hjj - mo_two_e_integrals_jj(occ(i,other_spin),iorb)
enddo
end
subroutine ac_operator(iorb,ispin,key,hjj,Nint,na,nb)
use bitmasks
implicit none
BEGIN_DOC
! Needed for :c:func:`diag_H_mat_elem`.
END_DOC
integer, intent(in) :: iorb, ispin, Nint
integer, intent(inout) :: na, nb
integer(bit_kind), intent(inout) :: key(Nint,2)
double precision, intent(inout) :: hjj
integer :: occ(Nint*bit_kind_size,2)
integer :: other_spin
integer :: k,l,i
if (iorb < 1) then
print *, irp_here, ': iorb < 1'
print *, iorb, mo_num
stop -1
endif
if (iorb > mo_num) then
print *, irp_here, ': iorb > mo_num'
print *, iorb, mo_num
stop -1
endif
ASSERT (ispin > 0)
ASSERT (ispin < 3)
ASSERT (Nint > 0)
integer :: tmp(2)
!DIR$ FORCEINLINE
call bitstring_to_list_ab(key, occ, tmp, Nint)
ASSERT (tmp(1) == elec_alpha_num)
ASSERT (tmp(2) == elec_beta_num)
k = shiftr(iorb-1,bit_kind_shift)+1
ASSERT (k >0)
l = iorb - shiftl(k-1,bit_kind_shift)-1
ASSERT (l >= 0)
key(k,ispin) = ibset(key(k,ispin),l)
other_spin = iand(ispin,1)+1
hjj = hjj + mo_one_e_integrals(iorb,iorb)
! Same spin
do i=1,na
hjj = hjj + mo_two_e_integrals_jj_anti(occ(i,ispin),iorb)
enddo
! Opposite spin
do i=1,nb
hjj = hjj + mo_two_e_integrals_jj(occ(i,other_spin),iorb)
enddo
na = na+1
end
subroutine get_phase(key1,key2,phase,Nint)
use bitmasks
implicit none
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key1(Nint,2), key2(Nint,2)
double precision, intent(out) :: phase
BEGIN_DOC
! Returns the phase between key1 and key2.
END_DOC
integer :: exc(0:2, 2, 2), degree
!DIR$ FORCEINLINE
call get_excitation(key1, key2, exc, degree, phase, Nint)
end
! Spin-determinant routines
! -------------------------
subroutine get_excitation_degree_spin(key1,key2,degree,Nint)
use bitmasks
include 'utils/constants.include.F'
implicit none
BEGIN_DOC
! Returns the excitation degree between two determinants.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key1(Nint)
integer(bit_kind), intent(in) :: key2(Nint)
integer, intent(out) :: degree
integer(bit_kind) :: xorvec(N_int_max)
integer :: l
ASSERT (Nint > 0)
select case (Nint)
case (1)
xorvec(1) = xor( key1(1), key2(1))
degree = popcnt(xorvec(1))
case (2)
xorvec(1) = xor( key1(1), key2(1))
xorvec(2) = xor( key1(2), key2(2))
degree = popcnt(xorvec(1))+popcnt(xorvec(2))
case (3)
xorvec(1) = xor( key1(1), key2(1))
xorvec(2) = xor( key1(2), key2(2))
xorvec(3) = xor( key1(3), key2(3))
degree = sum(popcnt(xorvec(1:3)))
case (4)
xorvec(1) = xor( key1(1), key2(1))
xorvec(2) = xor( key1(2), key2(2))
xorvec(3) = xor( key1(3), key2(3))
xorvec(4) = xor( key1(4), key2(4))
degree = sum(popcnt(xorvec(1:4)))
case default
do l=1,Nint
xorvec(l) = xor( key1(l), key2(l))
enddo
degree = sum(popcnt(xorvec(1:Nint)))
end select
degree = shiftr(degree,1)
end
subroutine get_excitation_spin(det1,det2,exc,degree,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the excitation operators between two determinants and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint)
integer(bit_kind), intent(in) :: det2(Nint)
integer, intent(out) :: exc(0:2,2)
integer, intent(out) :: degree
double precision, intent(out) :: phase
! exc(number,hole/particle)
! ex :
! exc(0,1) = number of holes
! exc(0,2) = number of particles
! exc(1,2) = first particle
! exc(1,1) = first hole
ASSERT (Nint > 0)
!DIR$ FORCEINLINE
call get_excitation_degree_spin(det1,det2,degree,Nint)
select case (degree)
case (3:)
degree = -1
return
case (2)
call get_double_excitation_spin(det1,det2,exc,phase,Nint)
return
case (1)
call get_single_excitation_spin(det1,det2,exc,phase,Nint)
return
case(0)
return
end select
end
subroutine decode_exc_spin(exc,h1,p1,h2,p2)
use bitmasks
implicit none
BEGIN_DOC
! Decodes the exc arrays returned by get_excitation.
!
! h1,h2 : Holes
!
! p1,p2 : Particles
END_DOC
integer, intent(in) :: exc(0:2,2)
integer, intent(out) :: h1,h2,p1,p2
select case (exc(0,1))
case(2)
h1 = exc(1,1)
h2 = exc(2,1)
p1 = exc(1,2)
p2 = exc(2,2)
case(1)
h1 = exc(1,1)
h2 = 0
p1 = exc(1,2)
p2 = 0
case default
h1 = 0
p1 = 0
h2 = 0
p2 = 0
end select
end
subroutine get_double_excitation_spin(det1,det2,exc,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the two excitation operators between two doubly excited spin-determinants
! and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint)
integer(bit_kind), intent(in) :: det2(Nint)
integer, intent(out) :: exc(0:2,2)
double precision, intent(out) :: phase
integer :: tz
integer :: l, idx_hole, idx_particle, ishift
integer :: nperm
integer :: i,j,k,m,n
integer :: high, low
integer :: a,b,c,d
integer(bit_kind) :: hole, particle, tmp
double precision, parameter :: phase_dble(0:1) = (/ 1.d0, -1.d0 /)
ASSERT (Nint > 0)
nperm = 0
exc(0,1) = 0
exc(0,2) = 0
idx_particle = 0
idx_hole = 0
ishift = 1-bit_kind_size
do l=1,Nint
ishift = ishift + bit_kind_size
if (det1(l) == det2(l)) then
cycle
endif
tmp = xor( det1(l), det2(l) )
particle = iand(tmp, det2(l))
hole = iand(tmp, det1(l))
do while (particle /= 0_bit_kind)
tz = trailz(particle)
idx_particle = idx_particle + 1
exc(0,2) = exc(0,2) + 1
exc(idx_particle,2) = tz+ishift
particle = iand(particle,particle-1_bit_kind)
enddo
if (iand(exc(0,1),exc(0,2))==2) then ! exc(0,1)==2 or exc(0,2)==2
exit
endif
do while (hole /= 0_bit_kind)
tz = trailz(hole)
idx_hole = idx_hole + 1
exc(0,1) = exc(0,1) + 1
exc(idx_hole,1) = tz+ishift
hole = iand(hole,hole-1_bit_kind)
enddo
if (iand(exc(0,1),exc(0,2))==2) then ! exc(0,1)==2 or exc(0,2)==2
exit
endif
enddo
select case (exc(0,1))
case(1)
low = min(exc(1,1), exc(1,2))
high = max(exc(1,1), exc(1,2))
ASSERT (low > 0)
j = shiftr(low-1,bit_kind_shift)+1 ! Find integer in array(Nint)
n = iand(low-1,bit_kind_size-1)+1 ! mod(low,bit_kind_size)
ASSERT (high > 0)
k = shiftr(high-1,bit_kind_shift)+1
m = iand(high-1,bit_kind_size-1)+1
if (j==k) then
nperm = nperm + popcnt(iand(det1(j), &
iand( ibset(0_bit_kind,m-1)-1_bit_kind, &
ibclr(-1_bit_kind,n)+1_bit_kind ) ))
else
nperm = nperm + popcnt(iand(det1(k), &
ibset(0_bit_kind,m-1)-1_bit_kind))
if (n < bit_kind_size) then
nperm = nperm + popcnt(iand(det1(j), ibclr(-1_bit_kind,n) +1_bit_kind))
endif
do i=j+1,k-1
nperm = nperm + popcnt(det1(i))
end do
endif
case (2)
do i=1,2
low = min(exc(i,1), exc(i,2))
high = max(exc(i,1), exc(i,2))
ASSERT (low > 0)
j = shiftr(low-1,bit_kind_shift)+1 ! Find integer in array(Nint)
n = iand(low-1,bit_kind_size-1)+1 ! mod(low,bit_kind_size)
ASSERT (high > 0)
k = shiftr(high-1,bit_kind_shift)+1
m = iand(high-1,bit_kind_size-1)+1
if (j==k) then
nperm = nperm + popcnt(iand(det1(j), &
iand( ibset(0_bit_kind,m-1)-1_bit_kind, &
ibclr(-1_bit_kind,n)+1_bit_kind ) ))
else
nperm = nperm + popcnt(iand(det1(k), &
ibset(0_bit_kind,m-1)-1_bit_kind))
if (n < bit_kind_size) then
nperm = nperm + popcnt(iand(det1(j), ibclr(-1_bit_kind,n) +1_bit_kind))
endif
do l=j+1,k-1
nperm = nperm + popcnt(det1(l))
end do
endif
enddo
a = min(exc(1,1), exc(1,2))
b = max(exc(1,1), exc(1,2))
c = min(exc(2,1), exc(2,2))
d = max(exc(2,1), exc(2,2))
if (c>a .and. c<b .and. d>b) then
nperm = nperm + 1
endif
end select
phase = phase_dble(iand(nperm,1))
end
subroutine get_single_excitation_spin(det1,det2,exc,phase,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Returns the excitation operator between two singly excited determinants and the phase.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: det1(Nint)
integer(bit_kind), intent(in) :: det2(Nint)
integer, intent(out) :: exc(0:2,2)
double precision, intent(out) :: phase
integer :: tz
integer :: l, idx_hole, idx_particle, ishift
integer :: nperm
integer :: i,j,k,m,n
integer :: high, low
integer :: a,b,c,d
integer(bit_kind) :: hole, particle, tmp
double precision, parameter :: phase_dble(0:1) = (/ 1.d0, -1.d0 /)
ASSERT (Nint > 0)
nperm = 0
exc(0,1) = 0
exc(0,2) = 0
ishift = 1-bit_kind_size
do l=1,Nint
ishift = ishift + bit_kind_size
if (det1(l) == det2(l)) then
cycle
endif
tmp = xor( det1(l), det2(l) )
particle = iand(tmp, det2(l))
hole = iand(tmp, det1(l))
if (particle /= 0_bit_kind) then
tz = trailz(particle)
exc(0,2) = 1
exc(1,2) = tz+ishift
endif
if (hole /= 0_bit_kind) then
tz = trailz(hole)
exc(0,1) = 1
exc(1,1) = tz+ishift
endif
if ( iand(exc(0,1),exc(0,2)) /= 1) then ! exc(0,1)/=1 and exc(0,2) /= 1
cycle
endif
low = min(exc(1,1),exc(1,2))
high = max(exc(1,1),exc(1,2))
ASSERT (low > 0)
j = shiftr(low-1,bit_kind_shift)+1 ! Find integer in array(Nint)
n = iand(low-1,bit_kind_size-1)+1 ! mod(low,bit_kind_size)
ASSERT (high > 0)
k = shiftr(high-1,bit_kind_shift)+1
m = iand(high-1,bit_kind_size-1)+1
if (j==k) then
nperm = popcnt(iand(det1(j), &
iand(ibset(0_bit_kind,m-1)-1_bit_kind,ibclr(-1_bit_kind,n)+1_bit_kind)))
else
nperm = nperm + popcnt(iand(det1(k),ibset(0_bit_kind,m-1)-1_bit_kind))
if (n < bit_kind_size) then
nperm = nperm + popcnt(iand(det1(j),ibclr(-1_bit_kind,n)+1_bit_kind))
endif
do i=j+1,k-1
nperm = nperm + popcnt(det1(i))
end do
endif
phase = phase_dble(iand(nperm,1))
return
enddo
end
subroutine i_H_j_single_spin(key_i,key_j,Nint,spin,hij)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ where $i$ and $j$ are determinants differing by
! a single excitation.
END_DOC
integer, intent(in) :: Nint, spin
integer(bit_kind), intent(in) :: key_i(Nint,2), key_j(Nint,2)
double precision, intent(out) :: hij
integer :: exc(0:2,2)
double precision :: phase
PROVIDE big_array_exchange_integrals mo_two_e_integrals_in_map
call get_single_excitation_spin(key_i(1,spin),key_j(1,spin),exc,phase,Nint)
call get_single_excitation_from_fock(key_i,key_j,exc(1,1),exc(1,2),spin,phase,hij)
end
subroutine i_H_j_double_spin(key_i,key_j,Nint,hij)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ where $i$ and $j$ are determinants differing by
! a same-spin double excitation.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint), key_j(Nint)
double precision, intent(out) :: hij
integer :: exc(0:2,2)
double precision :: phase
double precision, external :: get_two_e_integral
PROVIDE big_array_exchange_integrals mo_two_e_integrals_in_map
call get_double_excitation_spin(key_i,key_j,exc,phase,Nint)
hij = phase*(get_two_e_integral( &
exc(1,1), &
exc(2,1), &
exc(1,2), &
exc(2,2), mo_integrals_map) - &
get_two_e_integral( &
exc(1,1), &
exc(2,1), &
exc(2,2), &
exc(1,2), mo_integrals_map) )
end
subroutine i_H_j_double_alpha_beta(key_i,key_j,Nint,hij)
use bitmasks
implicit none
BEGIN_DOC
! Returns $\langle i|H|j \rangle$ where $i$ and $j$ are determinants differing by
! an opposite-spin double excitation.
END_DOC
integer, intent(in) :: Nint
integer(bit_kind), intent(in) :: key_i(Nint,2), key_j(Nint,2)
double precision, intent(out) :: hij
integer :: exc(0:2,2,2)
double precision :: phase, phase2
double precision, external :: get_two_e_integral
PROVIDE big_array_exchange_integrals mo_two_e_integrals_in_map
call get_single_excitation_spin(key_i(1,1),key_j(1,1),exc(0,1,1),phase,Nint)
call get_single_excitation_spin(key_i(1,2),key_j(1,2),exc(0,1,2),phase2,Nint)
phase = phase*phase2
if (exc(1,1,1) == exc(1,2,2)) then
hij = phase * big_array_exchange_integrals(exc(1,1,1),exc(1,1,2),exc(1,2,1))
else if (exc(1,2,1) == exc(1,1,2)) then
hij = phase * big_array_exchange_integrals(exc(1,2,1),exc(1,1,1),exc(1,2,2))
else
hij = phase*get_two_e_integral( &
exc(1,1,1), &
exc(1,1,2), &
exc(1,2,1), &
exc(1,2,2) ,mo_integrals_map)
endif
end
subroutine connected_to_hf(key_i,yes_no)
implicit none
use bitmasks
integer(bit_kind), intent(in) :: key_i(N_int,2)
logical , intent(out) :: yes_no
double precision :: hij,phase
integer :: exc(0:2,2,2)
integer :: degree
integer :: m,p
yes_no = .True.
call get_excitation_degree(ref_bitmask,key_i,degree,N_int)
if(degree == 2)then
call i_H_j(ref_bitmask,key_i,N_int,hij)
if(dabs(hij) .lt. thresh_sym)then
yes_no = .False.
endif
else if(degree == 1)then
call get_single_excitation(ref_bitmask,key_i,exc,phase,N_int)
! Single alpha
if (exc(0,1,1) == 1) then
m = exc(1,1,1)
p = exc(1,2,1)
! Single beta
else
m = exc(1,1,2)
p = exc(1,2,2)
endif
hij = mo_one_e_integrals(m,p)
if(dabs(hij) .lt. thresh_sym)then
yes_no = .False.
endif
else if(degree == 0)then
yes_no = .True.
endif
end
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