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qp2/src/casscf_cipsi/densities.irp.f

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2023-06-18 21:42:40 +02:00
use bitmasks
BEGIN_PROVIDER [real*8, D0tu, (n_act_orb,n_act_orb) ]
implicit none
BEGIN_DOC
! the first-order density matrix in the basis of the starting MOs.
! matrix is state averaged.
END_DOC
integer :: t,u
do u=1,n_act_orb
do t=1,n_act_orb
D0tu(t,u) = one_e_dm_mo_alpha_average( list_act(t), list_act(u) ) + &
one_e_dm_mo_beta_average ( list_act(t), list_act(u) )
enddo
enddo
END_PROVIDER
BEGIN_PROVIDER [real*8, P0tuvx, (n_act_orb,n_act_orb,n_act_orb,n_act_orb) ]
BEGIN_DOC
! The second-order density matrix in the basis of the starting MOs ONLY IN THE RANGE OF ACTIVE MOS
! The values are state averaged
!
! We use the spin-free generators of mono-excitations
! E_pq destroys q and creates p
! D_pq = <0|E_pq|0> = D_qp
! P_pqrs = 1/2 <0|E_pq E_rs - delta_qr E_ps|0>
!
! P0tuvx(p,q,r,s) = chemist notation : 1/2 <0|E_pq E_rs - delta_qr E_ps|0>
END_DOC
implicit none
integer :: t,u,v,x
integer :: tt,uu,vv,xx
integer :: mu,nu,istate,ispin,jspin,ihole,ipart,jhole,jpart
integer :: ierr
real*8 :: phase1,phase11,phase12,phase2,phase21,phase22
integer :: nu1,nu2,nu11,nu12,nu21,nu22
integer :: ierr1,ierr2,ierr11,ierr12,ierr21,ierr22
real*8 :: cI_mu(N_states),term
integer(bit_kind), dimension(N_int,2) :: det_mu, det_mu_ex
integer(bit_kind), dimension(N_int,2) :: det_mu_ex1, det_mu_ex11, det_mu_ex12
integer(bit_kind), dimension(N_int,2) :: det_mu_ex2, det_mu_ex21, det_mu_ex22
if (bavard) then
write(6,*) ' providing the 2 body RDM on the active part'
endif
P0tuvx= 0.d0
if(fast_2rdm)then
do istate=1,N_states
do x = 1, n_act_orb
do v = 1, n_act_orb
do u = 1, n_act_orb
do t = 1, n_act_orb
! 1 1 2 2 1 2 1 2
P0tuvx(t,u,v,x) = 0.5d0 * state_av_act_2_rdm_spin_trace_mo(t,v,u,x)
enddo
enddo
enddo
enddo
enddo
else
P0tuvx = P0tuvx_peter
endif
END_PROVIDER