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quantum_package/src/CISD/SC2.irp.f

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2014-05-19 18:35:56 +02:00
subroutine CISD_SC2(dets_in,u_in,energies,dim_in,sze,N_st,Nint)
use bitmasks
implicit none
BEGIN_DOC
! CISD+SC2 method :: take off all the disconnected terms of a CISD (selected or not)
!
! dets_in : bitmasks corresponding to determinants
!
! u_in : guess coefficients on the various states. Overwritten
! on exit
!
! dim_in : leftmost dimension of u_in
!
! sze : Number of determinants
!
! N_st : Number of eigenstates
!
! Initial guess vectors are not necessarily orthonormal
END_DOC
integer, intent(in) :: dim_in, sze, N_st, Nint
integer(bit_kind), intent(in) :: dets_in(Nint,2,sze)
double precision, intent(inout) :: u_in(dim_in,N_st)
double precision, intent(out) :: energies(N_st)
PROVIDE ref_bitmask_energy
ASSERT (N_st > 0)
ASSERT (sze > 0)
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
integer :: iter
integer :: i,j,k,l,m
logical :: converged
double precision :: overlap(N_st,N_st)
double precision :: u_dot_v, u_dot_u
integer :: degree,N_double,index_hf,index_double(sze)
double precision :: hij_elec, e_corr_double,e_corr,diag_h_mat_elem,inv_c0
double precision :: e_corr_array(sze),H_jj_ref(sze),H_jj_dressed(sze),hij_double(sze)
double precision :: e_corr_double_before,accu,cpu_2,cpu_1
integer :: i_ok
!$OMP PARALLEL DEFAULT(NONE) &
!$OMP SHARED(sze,N_st, &
!$OMP H_jj_ref,Nint,dets_in,u_in) &
!$OMP PRIVATE(i)
!$OMP DO
do i=1,sze
H_jj_ref(i) = diag_h_mat_elem(dets_in(1,1,i),Nint)
enddo
!$OMP END DO NOWAIT
!$OMP END PARALLEL
N_double = 0
e_corr = 0.d0
e_corr_double = 0.d0
do i = 1, sze
call get_excitation_degree(ref_bitmask,dets_in(1,1,i),degree,Nint)
if(degree==0)then
index_hf=i
else if (degree == 2)then
N_double += 1
index_double(N_double) = i
call i_H_j(ref_bitmask,dets_in(1,1,i),Nint,hij_elec)
hij_double(N_double) = hij_elec
e_corr_array(N_double) = u_in(i,1)* hij_elec
e_corr_double += e_corr_array(N_double)
e_corr += e_corr_array(N_double)
index_double(N_double) = i
else if (degree == 1)then
call i_H_j(ref_bitmask,dets_in(1,1,i),Nint,hij_elec)
print*,hij_elec
e_corr += u_in(i,1)* hij_elec
endif
enddo
inv_c0 = 1.d0/u_in(index_hf,1)
do i = 1, N_double
e_corr_array(i) = e_corr_array(i) * inv_c0
enddo
e_corr = e_corr * inv_c0
e_corr_double = e_corr_double * inv_c0
print*, 'E_corr = ',e_corr
print*, 'E_corr_double = ', e_corr_double
converged = .False.
e_corr_double_before = e_corr_double
iter = 0
do while (.not.converged)
iter +=1
print*,'SC2 iteration : ',iter
call cpu_time(cpu_1)
do i=1,sze
H_jj_dressed(i) = H_jj_ref(i)
if (i==index_hf)cycle
accu = 0.d0
do j=1,N_double
call repeat_excitation(dets_in(1,1,i),ref_bitmask,dets_in(1,1,index_double(j)),i_ok,Nint)
if (i_ok==1)cycle! you check if the excitation is possible
accu += e_corr_array(j)
enddo
H_jj_dressed(i) += accu
enddo
call cpu_time(cpu_2)
print*,'time for the excitations = ',cpu_2 - cpu_1
print*,H_jj_ref(1),H_jj_ref(2)
print*,H_jj_dressed(1),H_jj_dressed(2)
print*,u_in(index_hf,1),u_in(index_double(1),1)
call davidson_diag_hjj(dets_in,u_in,H_jj_dressed,energies,dim_in,sze,N_st,Nint)
print*,u_in(index_hf,1),u_in(index_double(1),1)
e_corr_double = 0.d0
inv_c0 = 1.d0/u_in(index_hf,1)
do i = 1, N_double
e_corr_array(i) = u_in(index_double(i),1)*inv_c0 * hij_double(i)
e_corr_double += e_corr_array(i)
enddo
print*,'E_corr = ',e_corr_double
print*,'delta E_corr =',e_corr_double - e_corr_double_before
converged = dabs(e_corr_double - e_corr_double_before) < 1.d-10
if (converged) then
exit
endif
e_corr_double_before = e_corr_double
enddo
end
subroutine davidson_diag_hjj(dets_in,u_in,H_jj,energies,dim_in,sze,N_st,Nint)
use bitmasks
implicit none
BEGIN_DOC
! Davidson diagonalization with specific diagonal elements of the H matrix
!
! H_jj : specific diagonal H matrix elements to diagonalize de Davidson
!
! dets_in : bitmasks corresponding to determinants
!
! u_in : guess coefficients on the various states. Overwritten
! on exit
!
! dim_in : leftmost dimension of u_in
!
! sze : Number of determinants
!
! N_st : Number of eigenstates
!
! Initial guess vectors are not necessarily orthonormal
END_DOC
integer, intent(in) :: dim_in, sze, N_st, Nint
integer(bit_kind), intent(in) :: dets_in(Nint,2,sze)
double precision, intent(in) :: H_jj(dim_in)
double precision, intent(inout) :: u_in(dim_in,N_st)
double precision, intent(out) :: energies(N_st)
integer :: iter
integer :: i,j,k,l,m
logical :: converged
double precision :: overlap(N_st,N_st)
double precision :: u_dot_v, u_dot_u
integer, allocatable :: kl_pairs(:,:)
integer :: k_pairs, kl
integer :: iter2
double precision, allocatable :: W(:,:,:), U(:,:,:), R(:,:)
double precision, allocatable :: y(:,:,:,:), h(:,:,:,:), lambda(:)
double precision :: diag_h_mat_elem
double precision :: residual_norm(N_st)
PROVIDE ref_bitmask_energy
allocate( &
kl_pairs(2,N_st*(N_st+1)/2), &
W(sze,N_st,davidson_sze_max), &
U(sze,N_st,davidson_sze_max), &
R(sze,N_st), &
h(N_st,davidson_sze_max,N_st,davidson_sze_max), &
y(N_st,davidson_sze_max,N_st,davidson_sze_max), &
lambda(N_st*davidson_sze_max))
ASSERT (N_st > 0)
ASSERT (sze > 0)
ASSERT (Nint > 0)
ASSERT (Nint == N_int)
! Initialization
! ==============
k_pairs=0
do l=1,N_st
do k=1,l
k_pairs+=1
kl_pairs(1,k_pairs) = k
kl_pairs(2,k_pairs) = l
enddo
enddo
!$OMP PARALLEL DEFAULT(NONE) &
!$OMP SHARED(U,sze,N_st,overlap,kl_pairs,k_pairs, &
!$OMP Nint,dets_in,u_in) &
!$OMP PRIVATE(k,l,kl,i)
! Orthonormalize initial guess
! ============================
!$OMP DO
do kl=1,k_pairs
k = kl_pairs(1,kl)
l = kl_pairs(2,kl)
if (k/=l) then
overlap(k,l) = u_dot_v(U_in(1,k),U_in(1,l),sze)
overlap(l,k) = overlap(k,l)
else
overlap(k,k) = u_dot_u(U_in(1,k),sze)
endif
enddo
!$OMP END DO
!$OMP END PARALLEL
call ortho_lowdin(overlap,size(overlap,1),N_st,U_in,size(U_in,1),sze)
! Davidson iterations
! ===================
converged = .False.
do while (.not.converged)
!$OMP PARALLEL DEFAULT(NONE) &
!$OMP PRIVATE(k,i) SHARED(U,u_in,sze,N_st)
do k=1,N_st
!$OMP DO
do i=1,sze
U(i,k,1) = u_in(i,k)
enddo
!$OMP END DO
enddo
!$OMP END PARALLEL
do iter=1,davidson_sze_max-1
! Compute W_k = H |u_k>
! ----------------------
do k=1,N_st
call H_u_0(W(1,k,iter),U(1,k,iter),H_jj,sze,dets_in,Nint)
enddo
! Compute h_kl = <u_k | W_l> = <u_k| H |u_l>
! -------------------------------------------
do l=1,N_st
do k=1,N_st
do iter2=1,iter-1
h(k,iter2,l,iter) = u_dot_v(U(1,k,iter2),W(1,l,iter),sze)
h(k,iter,l,iter2) = h(k,iter2,l,iter)
enddo
enddo
do k=1,l
h(k,iter,l,iter) = u_dot_v(U(1,k,iter),W(1,l,iter),sze)
h(l,iter,k,iter) = h(k,iter,l,iter)
enddo
enddo
! Diagonalize h
! -------------
call lapack_diag(lambda,y,h,N_st*davidson_sze_max,N_st*iter)
! Express eigenvectors of h in the determinant basis
! --------------------------------------------------
! call dgemm ( 'N','N', sze, N_st*iter, N_st, &
! 1.d0, U(1,1,1), size(U,1), y(1,1,1,1), size(y,1)*size(y,2), &
! 0.d0, U(1,1,iter+1), size(U,1) )
do k=1,N_st
do i=1,sze
U(i,k,iter+1) = 0.d0
W(i,k,iter+1) = 0.d0
do l=1,N_st
do iter2=1,iter
U(i,k,iter+1) = U(i,k,iter+1) + U(i,l,iter2)*y(l,iter2,k,1)
W(i,k,iter+1) = W(i,k,iter+1) + W(i,l,iter2)*y(l,iter2,k,1)
enddo
enddo
enddo
enddo
! Compute residual vector
! -----------------------
do k=1,N_st
do i=1,sze
R(i,k) = lambda(k) * U(i,k,iter+1) - W(i,k,iter+1)
enddo
residual_norm(k) = u_dot_u(R(1,k),sze)
enddo
print '(I3,15(F16.8,x))', iter, lambda(1:N_st) + nuclear_repulsion
print '(3x,15(E16.5,x))', residual_norm(1:N_st)
converged = maxval(residual_norm) < 1.d-10
if (converged) then
exit
endif
! Davidson step
! -------------
do k=1,N_st
do i=1,sze
U(i,k,iter+1) = 1.d0/(lambda(k) - H_jj(i)) * R(i,k)
enddo
enddo
! Gram-Schmidt
! ------------
double precision :: c
do k=1,N_st
do iter2=1,iter
do l=1,N_st
c = u_dot_v(U(1,k,iter+1),U(1,l,iter2),sze)
do i=1,sze
U(i,k,iter+1) -= c * U(i,l,iter2)
enddo
enddo
enddo
do l=1,k-1
c = u_dot_v(U(1,k,iter+1),U(1,l,iter+1),sze)
do i=1,sze
U(i,k,iter+1) -= c * U(i,l,iter+1)
enddo
enddo
call normalize( U(1,k,iter+1), sze )
enddo
enddo
if (.not.converged) then
iter = davidson_sze_max-1
endif
! Re-contract to u_in
! -----------
do k=1,N_st
energies(k) = lambda(k)
do i=1,sze
u_in(i,k) = 0.d0
do iter2=1,iter
do l=1,N_st
u_in(i,k) += U(i,l,iter2)*y(l,iter2,k,1)
enddo
enddo
enddo
enddo
enddo
deallocate ( &
kl_pairs, &
W, &
U, &
R, &
h, &
y, &
lambda &
)
end
subroutine repeat_excitation(key_in,key_1,key_2,i_ok,Nint)
use bitmasks
implicit none
integer(bit_kind), intent(in) :: key_in(Nint,2),key_1(Nint,2),key_2(Nint,2),Nint
integer,intent(out):: i_ok
integer :: ispin,i_hole,k_hole,j_hole,i_particl,k_particl,j_particl,i_trou,degree,exc(0:2,2,2)
double precision :: phase
i_ok = 1
call get_excitation(key_1,key_2,exc,degree,phase,Nint)
integer :: h1,p1,h2,p2,s1,s2
if(degree==2)then
call decode_exc(exc,degree,h1,p1,h2,p2,s1,s2)
! first hole
k_hole = ishft(h1-1,-5)+1
j_hole = h1-ishft(k_hole-1,5)-1
if(iand(key_in(k_hole,s1),ibset(0,j_hole)).eq.0)then
i_ok = 0
return
endif
! second hole
k_hole = ishft(h2-1,-5)+1
j_hole = h2-ishft(k_hole-1,5)-1
if(iand(key_in(k_hole,s2),ibset(0,j_hole)).eq.0)then
i_ok = 0
return
endif
! first particle
k_particl = ishft(p1-1,-5)+1
j_particl = p1-ishft(k_particl-1,5)-1
if(iand(key_in(k_particl,s1),ibset(0,j_particl)).ne.0)then
i_ok = 0
return
endif
! second particle
k_particl = ishft(p2-1,-5)+1
j_particl = p2-ishft(k_particl-1,5)-1
if(iand(key_in(k_particl,s2),ibset(0,j_particl)).ne.0)then
i_ok = 0
return
endif
return
endif
end