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mirror of https://github.com/QuantumPackage/qp2.git synced 2024-11-02 03:33:37 +01:00
qp2/src/mo_guess/mo_ortho_lowdin.irp.f

50 lines
1.4 KiB
Fortran

BEGIN_PROVIDER [double precision, ao_ortho_lowdin_coef, (ao_num,ao_num)]
implicit none
BEGIN_DOC
! matrix of the coefficients of the mos generated by the
! orthonormalization by the S^{-1/2} canonical transformation of the aos
! ao_ortho_lowdin_coef(i,j) = coefficient of the ith ao on the jth ao_ortho_lowdin orbital
END_DOC
integer :: i,j,k,l
double precision :: accu
double precision, allocatable :: tmp_matrix(:,:)
allocate (tmp_matrix(ao_num,ao_num))
tmp_matrix(:,:) = 0.d0
do j=1, ao_num
tmp_matrix(j,j) = 1.d0
enddo
call ortho_lowdin(ao_overlap,ao_num,ao_num,tmp_matrix,ao_num,ao_num,lin_dep_cutoff)
do i=1, ao_num
do j=1, ao_num
ao_ortho_lowdin_coef(j,i) = tmp_matrix(i,j)
enddo
enddo
deallocate(tmp_matrix)
END_PROVIDER
BEGIN_PROVIDER [double precision, ao_ortho_lowdin_overlap, (ao_num,ao_num)]
implicit none
BEGIN_DOC
! overlap matrix of the ao_ortho_lowdin
! supposed to be the Identity
END_DOC
integer :: i,j,k,l
double precision :: c
do j=1, ao_num
do i=1, ao_num
ao_ortho_lowdin_overlap(i,j) = 0.d0
enddo
enddo
do k=1, ao_num
do j=1, ao_num
c = 0.d0
do l=1, ao_num
c += ao_ortho_lowdin_coef(j,l) * ao_overlap(k,l)
enddo
do i=1, ao_num
ao_ortho_lowdin_overlap(i,j) += ao_ortho_lowdin_coef(i,k) * c
enddo
enddo
enddo
END_PROVIDER