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quantum_package/plugins/MRCC_Utils/multi_state.irp.f

102 lines
2.6 KiB
Fortran

subroutine multi_state(CI_electronic_energy_dressed_,CI_eigenvectors_dressed_,LDA)
implicit none
BEGIN_DOC
! Multi-state mixing
END_DOC
integer, intent(in) :: LDA
double precision, intent(inout) :: CI_electronic_energy_dressed_(N_states)
double precision, intent(inout) :: CI_eigenvectors_dressed_(LDA,N_states)
double precision, allocatable :: h(:,:,:), s(:,:), Psi(:,:), H_Psi(:,:,:), H_jj(:)
allocate( h(N_states,N_states,0:N_states), s(N_states,N_states) )
allocate( Psi(LDA,N_states), H_Psi(LDA,N_states,0:N_states) )
allocate (H_jj(LDA) )
! e_0(i) = u_dot_v(v_0(1,i),u_0(1,i),n)/u_dot_u(u_0(1,i),n)
integer :: i,j,k,istate
double precision :: U(N_states,N_states), Vt(N_states,N_states), D(N_states)
double precision, external :: diag_H_mat_elem
do istate=1,N_states
do i=1,N_det
H_jj(i) = diag_H_mat_elem(psi_det(1,1,i),N_int)
enddo
do i=1,N_det_ref
H_jj(idx_ref(i)) += delta_ii(istate,i)
enddo
do k=1,N_states
do i=1,N_det
Psi(i,k) = CI_eigenvectors_dressed_(i,k)
enddo
enddo
call H_u_0_mrcc_nstates(H_Psi(1,1,istate),Psi,H_jj,N_det,psi_det,N_int,istate,N_states,LDA)
do k=1,N_states
do i=1,N_states
double precision, external :: u_dot_v
h(i,k,istate) = u_dot_v(Psi(1,i), H_Psi(1,k,istate), N_det)
enddo
enddo
enddo
do k=1,N_states
do i=1,N_states
s(i,k) = u_dot_v(Psi(1,i), Psi(1,k), N_det)
enddo
enddo
print *, s(:,:)
print *, ''
h(:,:,0) = h(:,:,1)
do istate=2,N_states
U(:,:) = h(:,:,0)
call dgemm('N','N',N_states,N_states,N_states,1.d0,&
U, size(U,1), h(1,1,istate), size(h,1), 0.d0, &
h(1,1,0), size(Vt,1))
enddo
call svd(h(1,1,0), size(h,1), U, size(U,1), D, Vt, size(Vt,1), N_states, N_states)
do k=1,N_states
D(k) = D(k)**(1./dble(N_states))
if (D(k) > 0.d0) then
D(k) = -D(k)
endif
enddo
do j=1,N_states
do i=1,N_states
h(i,j,0) = 0.d0
do k=1,N_states
h(i,j,0) += U(i,k) * D(k) * Vt(k,j)
enddo
enddo
enddo
print *, h(:,:,0)
print *,''
integer :: LWORK, INFO
double precision, allocatable :: WORK(:)
LWORK=3*N_states
allocate (WORK(LWORK))
call dsygv(1, 'V', 'U', N_states, h(1,1,0), size(h,1), s, size(s,1), D, WORK, LWORK, INFO)
deallocate(WORK)
do j=1,N_states
do i=1,N_det
CI_eigenvectors_dressed_(i,j) = 0.d0
do k=1,N_states
CI_eigenvectors_dressed_(i,j) += Psi(i,k) * h(k,j,0)
enddo
enddo
CI_electronic_energy_dressed_(j) = D(j)
enddo
deallocate (h,s, H_jj)
deallocate( Psi, H_Psi )
end