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qp2/src/davidson/diagonalize_ci.irp.f
2022-02-04 11:09:33 +01:00

261 lines
9.8 KiB
Fortran

BEGIN_PROVIDER [ double precision, CI_energy, (N_states_diag) ]
implicit none
BEGIN_DOC
! :c:data:`n_states` lowest eigenvalues of the |CI| matrix
END_DOC
PROVIDE distributed_davidson
integer :: j
character*(8) :: st
call write_time(6)
do j=1,min(N_det,N_states_diag)
CI_energy(j) = CI_electronic_energy(j) + nuclear_repulsion
enddo
do j=1,min(N_det,N_states)
write(st,'(I4)') j
call write_double(6,CI_energy(j),'Energy of state '//trim(st))
call write_double(6,CI_s2(j),'S^2 of state '//trim(st))
enddo
END_PROVIDER
BEGIN_PROVIDER [ double precision, CI_electronic_energy, (N_states_diag) ]
&BEGIN_PROVIDER [ double precision, CI_eigenvectors, (N_det,N_states_diag) ]
&BEGIN_PROVIDER [ double precision, CI_s2, (N_states_diag) ]
BEGIN_DOC
! Eigenvectors/values of the |CI| matrix
END_DOC
implicit none
double precision :: ovrlp,u_dot_v
integer :: i_good_state
integer, allocatable :: index_good_state_array(:)
logical, allocatable :: good_state_array(:)
double precision, allocatable :: s2_values_tmp(:)
integer :: i_other_state
double precision, allocatable :: eigenvectors(:,:), eigenvalues(:), H_prime(:,:)
integer :: i_state
double precision :: e_0
integer :: i,j,k
double precision, allocatable :: s2_eigvalues(:)
double precision, allocatable :: e_array(:)
integer, allocatable :: iorder(:)
logical :: converged
logical :: do_csf
PROVIDE threshold_davidson nthreads_davidson distributed_davidson
! Guess values for the "N_states" states of the |CI| eigenvectors
do j=1,min(N_states,N_det)
do i=1,N_det
CI_eigenvectors(i,j) = psi_coef(i,j)
enddo
enddo
do j=min(N_states,N_det)+1,N_states_diag
do i=1,N_det
CI_eigenvectors(i,j) = 0.d0
enddo
enddo
do_csf = s2_eig .and. only_expected_s2 .and. csf_based
if (diag_algorithm == "Davidson") then
if (do_csf) then
call davidson_diag_H_csf(psi_det,CI_eigenvectors, &
size(CI_eigenvectors,1),CI_electronic_energy, &
N_det,N_csf,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
else
call davidson_diag_HS2(psi_det,CI_eigenvectors, CI_s2, &
size(CI_eigenvectors,1),CI_electronic_energy, &
N_det,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
endif
integer :: N_states_diag_save
N_states_diag_save = N_states_diag
do while (.not.converged)
double precision, allocatable :: CI_electronic_energy_tmp (:)
double precision, allocatable :: CI_eigenvectors_tmp (:,:)
double precision, allocatable :: CI_s2_tmp (:)
N_states_diag *= 2
TOUCH N_states_diag
if (do_csf) then
allocate (CI_electronic_energy_tmp (N_states_diag) )
allocate (CI_eigenvectors_tmp (N_det,N_states_diag) )
CI_electronic_energy_tmp(1:N_states_diag_save) = CI_electronic_energy(1:N_states_diag_save)
CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save) = CI_eigenvectors(1:N_det,1:N_states_diag_save)
call davidson_diag_H_csf(psi_det,CI_eigenvectors_tmp, &
size(CI_eigenvectors_tmp,1),CI_electronic_energy_tmp, &
N_det,N_csf,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
CI_electronic_energy(1:N_states_diag_save) = CI_electronic_energy_tmp(1:N_states_diag_save)
CI_eigenvectors(1:N_det,1:N_states_diag_save) = CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save)
deallocate (CI_electronic_energy_tmp)
deallocate (CI_eigenvectors_tmp)
else
allocate (CI_electronic_energy_tmp (N_states_diag) )
allocate (CI_eigenvectors_tmp (N_det,N_states_diag) )
allocate (CI_s2_tmp (N_states_diag) )
CI_electronic_energy_tmp(1:N_states_diag_save) = CI_electronic_energy(1:N_states_diag_save)
CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save) = CI_eigenvectors(1:N_det,1:N_states_diag_save)
CI_s2_tmp(1:N_states_diag_save) = CI_s2(1:N_states_diag_save)
call davidson_diag_HS2(psi_det,CI_eigenvectors_tmp, CI_s2_tmp, &
size(CI_eigenvectors_tmp,1),CI_electronic_energy_tmp, &
N_det,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
CI_electronic_energy(1:N_states_diag_save) = CI_electronic_energy_tmp(1:N_states_diag_save)
CI_eigenvectors(1:N_det,1:N_states_diag_save) = CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save)
CI_s2(1:N_states_diag_save) = CI_s2_tmp(1:N_states_diag_save)
deallocate (CI_electronic_energy_tmp)
deallocate (CI_eigenvectors_tmp)
deallocate (CI_s2_tmp)
endif
enddo
if (N_states_diag > N_states_diag_save) then
N_states_diag = N_states_diag_save
TOUCH N_states_diag
endif
else if (diag_algorithm == "Lapack") then
print *, 'Diagonalization of H using Lapack'
allocate (eigenvectors(size(H_matrix_all_dets,1),N_det))
allocate (eigenvalues(N_det))
if (s2_eig) then
double precision, parameter :: alpha = 0.1d0
allocate (H_prime(N_det,N_det) )
H_prime(1:N_det,1:N_det) = H_matrix_all_dets(1:N_det,1:N_det) + &
alpha * S2_matrix_all_dets(1:N_det,1:N_det)
do j=1,N_det
H_prime(j,j) = H_prime(j,j) - alpha*expected_s2
enddo
call lapack_diag(eigenvalues,eigenvectors,H_prime,size(H_prime,1),N_det)
call nullify_small_elements(N_det,N_det,eigenvectors,size(eigenvectors,1),1.d-12)
CI_electronic_energy(:) = 0.d0
i_state = 0
allocate (s2_eigvalues(N_det))
allocate(index_good_state_array(N_det),good_state_array(N_det))
good_state_array = .False.
call u_0_S2_u_0(s2_eigvalues,eigenvectors,N_det,psi_det,N_int,&
N_det,size(eigenvectors,1))
if (only_expected_s2) then
do j=1,N_det
! Select at least n_states states with S^2 values closed to "expected_s2"
if(dabs(s2_eigvalues(j)-expected_s2).le.0.5d0)then
i_state +=1
index_good_state_array(i_state) = j
good_state_array(j) = .True.
endif
if(i_state.eq.N_states) then
exit
endif
enddo
else
do j=1,N_det
index_good_state_array(j) = j
good_state_array(j) = .True.
enddo
endif
if(i_state .ne.0)then
! Fill the first "i_state" states that have a correct S^2 value
do j = 1, i_state
do i=1,N_det
CI_eigenvectors(i,j) = eigenvectors(i,index_good_state_array(j))
enddo
CI_electronic_energy(j) = eigenvalues(index_good_state_array(j))
CI_s2(j) = s2_eigvalues(index_good_state_array(j))
enddo
i_other_state = 0
do j = 1, N_det
if(good_state_array(j))cycle
i_other_state +=1
if(i_state+i_other_state.gt.n_states_diag)then
exit
endif
do i=1,N_det
CI_eigenvectors(i,i_state+i_other_state) = eigenvectors(i,j)
enddo
CI_electronic_energy(i_state+i_other_state) = eigenvalues(j)
CI_s2(i_state+i_other_state) = s2_eigvalues(i_state+i_other_state)
enddo
else
print*,''
print*,'!!!!!!!! WARNING !!!!!!!!!'
print*,' Within the ',N_det,'determinants selected'
print*,' and the ',N_states_diag,'states requested'
print*,' We did not find only states with S^2 values close to ',expected_s2
print*,' We will then set the first N_states eigenvectors of the H matrix'
print*,' as the CI_eigenvectors'
print*,' You should consider more states and maybe ask for s2_eig to be .True. or just enlarge the CI space'
print*,''
do j=1,min(N_states_diag,N_det)
do i=1,N_det
CI_eigenvectors(i,j) = eigenvectors(i,j)
enddo
CI_electronic_energy(j) = eigenvalues(j)
CI_s2(j) = s2_eigvalues(j)
enddo
endif
deallocate(index_good_state_array,good_state_array)
deallocate(s2_eigvalues)
else
call lapack_diag(eigenvalues,eigenvectors, &
H_matrix_all_dets,size(H_matrix_all_dets,1),N_det)
CI_electronic_energy(:) = 0.d0
call u_0_S2_u_0(CI_s2,eigenvectors,N_det,psi_det,N_int, &
min(N_det,N_states_diag),size(eigenvectors,1))
! Select the "N_states_diag" states of lowest energy
do j=1,min(N_det,N_states_diag)
do i=1,N_det
CI_eigenvectors(i,j) = eigenvectors(i,j)
enddo
CI_electronic_energy(j) = eigenvalues(j)
enddo
endif
do k=1,N_states_diag
CI_electronic_energy(k) = 0.d0
do j=1,N_det
do i=1,N_det
CI_electronic_energy(k) += &
CI_eigenvectors(i,k) * CI_eigenvectors(j,k) * &
H_matrix_all_dets(i,j)
enddo
enddo
enddo
deallocate(eigenvectors,eigenvalues)
endif
END_PROVIDER
subroutine diagonalize_CI
implicit none
BEGIN_DOC
! Replace the coefficients of the |CI| states by the coefficients of the
! eigenstates of the |CI| matrix.
END_DOC
integer :: i,j
PROVIDE distributed_davidson
do j=1,N_states
do i=1,N_det
psi_coef(i,j) = CI_eigenvectors(i,j)
enddo
enddo
psi_energy(1:N_states) = CI_electronic_energy(1:N_states)
psi_s2(1:N_states) = CI_s2(1:N_states)
SOFT_TOUCH psi_coef CI_electronic_energy CI_energy CI_eigenvectors CI_s2 psi_energy psi_s2
end