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https://github.com/QuantumPackage/qp2.git
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210 lines
7.8 KiB
Fortran
210 lines
7.8 KiB
Fortran
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BEGIN_PROVIDER [ double precision, CI_energy, (N_states_diag) ]
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implicit none
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BEGIN_DOC
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! :c:data:`n_states` lowest eigenvalues of the |CI| matrix
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END_DOC
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integer :: j
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character*(8) :: st
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call write_time(6)
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do j=1,min(N_det,N_states_diag)
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CI_energy(j) = CI_electronic_energy(j) + nuclear_repulsion
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enddo
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do j=1,min(N_det,N_states)
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write(st,'(I4)') j
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call write_double(6,CI_energy(j),'Energy of state '//trim(st))
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call write_double(6,CI_s2(j),'S^2 of state '//trim(st))
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enddo
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END_PROVIDER
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BEGIN_PROVIDER [ double precision, CI_electronic_energy, (N_states_diag) ]
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&BEGIN_PROVIDER [ double precision, CI_eigenvectors, (N_det,N_states_diag) ]
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&BEGIN_PROVIDER [ double precision, CI_s2, (N_states_diag) ]
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BEGIN_DOC
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! Eigenvectors/values of the |CI| matrix
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END_DOC
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implicit none
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double precision :: ovrlp,u_dot_v
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integer :: i_good_state
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integer, allocatable :: index_good_state_array(:)
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logical, allocatable :: good_state_array(:)
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double precision, allocatable :: s2_values_tmp(:)
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integer :: i_other_state
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double precision, allocatable :: eigenvectors(:,:), eigenvalues(:), H_prime(:,:)
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integer :: i_state
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double precision :: e_0
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integer :: i,j,k
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double precision, allocatable :: s2_eigvalues(:)
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double precision, allocatable :: e_array(:)
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integer, allocatable :: iorder(:)
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logical :: converged
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PROVIDE threshold_davidson nthreads_davidson
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! Guess values for the "N_states" states of the |CI| eigenvectors
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do j=1,min(N_states,N_det)
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do i=1,N_det
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CI_eigenvectors(i,j) = psi_coef(i,j)
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enddo
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enddo
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do j=min(N_states,N_det)+1,N_states_diag
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do i=1,N_det
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CI_eigenvectors(i,j) = 0.d0
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enddo
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enddo
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if (diag_algorithm == "Davidson") then
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call davidson_diag_HS2(psi_det,CI_eigenvectors, CI_s2, &
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size(CI_eigenvectors,1),CI_electronic_energy, &
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N_det,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
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integer :: N_states_diag_save
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N_states_diag_save = N_states_diag
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do while (.not.converged)
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double precision, allocatable :: CI_electronic_energy_tmp (:)
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double precision, allocatable :: CI_eigenvectors_tmp (:,:)
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double precision, allocatable :: CI_s2_tmp (:)
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N_states_diag *= 2
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TOUCH N_states_diag
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allocate (CI_electronic_energy_tmp (N_states_diag) )
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allocate (CI_eigenvectors_tmp (N_det,N_states_diag) )
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allocate (CI_s2_tmp (N_states_diag) )
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CI_electronic_energy_tmp(1:N_states_diag_save) = CI_electronic_energy(1:N_states_diag_save)
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CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save) = CI_eigenvectors(1:N_det,1:N_states_diag_save)
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CI_s2_tmp(1:N_states_diag_save) = CI_s2(1:N_states_diag_save)
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call davidson_diag_HS2(psi_det,CI_eigenvectors_tmp, CI_s2_tmp, &
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size(CI_eigenvectors_tmp,1),CI_electronic_energy_tmp, &
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N_det,min(N_det,N_states),min(N_det,N_states_diag),N_int,0,converged)
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CI_electronic_energy(1:N_states_diag_save) = CI_electronic_energy_tmp(1:N_states_diag_save)
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CI_eigenvectors(1:N_det,1:N_states_diag_save) = CI_eigenvectors_tmp(1:N_det,1:N_states_diag_save)
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CI_s2(1:N_states_diag_save) = CI_s2_tmp(1:N_states_diag_save)
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deallocate (CI_electronic_energy_tmp)
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deallocate (CI_eigenvectors_tmp)
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deallocate (CI_s2_tmp)
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enddo
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if (N_states_diag > N_states_diag_save) then
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N_states_diag = N_states_diag_save
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TOUCH N_states_diag
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endif
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else if (diag_algorithm == "Lapack") then
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print *, 'Diagonalization of H using Lapack'
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allocate (eigenvectors(size(H_matrix_all_dets,1),N_det))
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allocate (eigenvalues(N_det))
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if (s2_eig) then
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double precision, parameter :: alpha = 0.1d0
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allocate (H_prime(N_det,N_det) )
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H_prime(1:N_det,1:N_det) = H_matrix_all_dets(1:N_det,1:N_det) + &
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alpha * S2_matrix_all_dets(1:N_det,1:N_det)
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do j=1,N_det
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H_prime(j,j) = H_prime(j,j) + alpha*(S_z2_Sz - expected_s2)
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enddo
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call lapack_diag(eigenvalues,eigenvectors,H_prime,size(H_prime,1),N_det)
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CI_electronic_energy(:) = 0.d0
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i_state = 0
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allocate (s2_eigvalues(N_det))
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allocate(index_good_state_array(N_det),good_state_array(N_det))
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good_state_array = .False.
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call u_0_S2_u_0(s2_eigvalues,eigenvectors,N_det,psi_det,N_int,&
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N_det,size(eigenvectors,1))
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do j=1,N_det
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! Select at least n_states states with S^2 values closed to "expected_s2"
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if(dabs(s2_eigvalues(j)-expected_s2).le.0.5d0)then
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i_state +=1
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index_good_state_array(i_state) = j
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good_state_array(j) = .True.
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endif
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if(i_state.eq.N_states) then
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exit
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endif
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enddo
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if(i_state .ne.0)then
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! Fill the first "i_state" states that have a correct S^2 value
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do j = 1, i_state
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do i=1,N_det
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CI_eigenvectors(i,j) = eigenvectors(i,index_good_state_array(j))
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enddo
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CI_electronic_energy(j) = eigenvalues(index_good_state_array(j))
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CI_s2(j) = s2_eigvalues(index_good_state_array(j))
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enddo
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i_other_state = 0
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do j = 1, N_det
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if(good_state_array(j))cycle
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i_other_state +=1
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if(i_state+i_other_state.gt.n_states_diag)then
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exit
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endif
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do i=1,N_det
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CI_eigenvectors(i,i_state+i_other_state) = eigenvectors(i,j)
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enddo
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CI_electronic_energy(i_state+i_other_state) = eigenvalues(j)
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CI_s2(i_state+i_other_state) = s2_eigvalues(i_state+i_other_state)
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enddo
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else
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print*,''
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print*,'!!!!!!!! WARNING !!!!!!!!!'
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print*,' Within the ',N_det,'determinants selected'
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print*,' and the ',N_states_diag,'states requested'
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print*,' We did not find any state with S^2 values close to ',expected_s2
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print*,' We will then set the first N_states eigenvectors of the H matrix'
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print*,' as the CI_eigenvectors'
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print*,' You should consider more states and maybe ask for s2_eig to be .True. or just enlarge the CI space'
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print*,''
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do j=1,min(N_states_diag,N_det)
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do i=1,N_det
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CI_eigenvectors(i,j) = eigenvectors(i,j)
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enddo
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CI_electronic_energy(j) = eigenvalues(j)
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CI_s2(j) = s2_eigvalues(j)
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enddo
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endif
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deallocate(index_good_state_array,good_state_array)
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deallocate(s2_eigvalues)
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else
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call lapack_diag(eigenvalues,eigenvectors, &
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H_matrix_all_dets,size(H_matrix_all_dets,1),N_det)
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CI_electronic_energy(:) = 0.d0
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call u_0_S2_u_0(CI_s2,eigenvectors,N_det,psi_det,N_int,&
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min(N_det,N_states_diag),size(eigenvectors,1))
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! Select the "N_states_diag" states of lowest energy
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do j=1,min(N_det,N_states_diag)
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do i=1,N_det
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CI_eigenvectors(i,j) = eigenvectors(i,j)
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enddo
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CI_electronic_energy(j) = eigenvalues(j)
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enddo
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endif
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deallocate(eigenvectors,eigenvalues)
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endif
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END_PROVIDER
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subroutine diagonalize_CI
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implicit none
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BEGIN_DOC
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! Replace the coefficients of the |CI| states by the coefficients of the
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! eigenstates of the |CI| matrix.
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END_DOC
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integer :: i,j
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do j=1,N_states
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do i=1,N_det
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psi_coef(i,j) = CI_eigenvectors(i,j)
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enddo
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enddo
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psi_energy(1:N_states) = CI_electronic_energy(1:N_states)
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psi_s2(1:N_states) = CI_s2(1:N_states)
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SOFT_TOUCH psi_coef CI_electronic_energy CI_energy CI_eigenvectors CI_s2 psi_energy psi_s2
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end
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