subroutine $subroutine($params_main)
  implicit none
  use omp_lib
  use bitmasks
  BEGIN_DOC
  ! Calls H_apply on the HF determinant and selects all connected single and double
  ! excitations (of the same symmetry). Auto-generated by the ``generate_h_apply`` script.
  END_DOC
  
  $decls_main
  
  integer                        :: i_generator, nmax
  double precision               :: wall_0, wall_1
  integer(omp_lock_kind)         :: lck
  integer(bit_kind), allocatable :: mask(:,:,:)
  integer                        :: ispin, k
  integer                        :: iproc
  double precision, allocatable  :: fock_diag_tmp(:,:)

  $initialization
  PROVIDE H_apply_buffer_allocated mo_bielec_integrals_in_map psi_det_generators psi_coef_generators

  
  nmax = mod( N_det_generators,nproc )

  !$ call omp_init_lock(lck)

  call wall_time(wall_0)

  iproc = 0
  allocate( mask(N_int,2,6), fock_diag_tmp(2,mo_tot_num+1) )
  do i_generator=1,nmax

    $skip

    ! Compute diagonal of the Fock matrix
    call build_fock_tmp(fock_diag_tmp,psi_det_generators(1,1,i_generator),N_int)

    ! Create bit masks for holes and particles
    do ispin=1,2
      do k=1,N_int
        mask(k,ispin,s_hole) =                                      &
            iand(generators_bitmask(k,ispin,s_hole,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,s_part) =                                      &
            iand(generators_bitmask(k,ispin,s_part,i_bitmask_gen),  &
            not(psi_det_generators(k,ispin,i_generator)) )
        mask(k,ispin,d_hole1) =                                      &
            iand(generators_bitmask(k,ispin,d_hole1,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,d_part1) =                                      &
            iand(generators_bitmask(k,ispin,d_part1,i_bitmask_gen),  &
            not(psi_det_generators(k,ispin,i_generator)) )
        mask(k,ispin,d_hole2) =                                      &
            iand(generators_bitmask(k,ispin,d_hole2,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,d_part2) =                                      &
            iand(generators_bitmask(k,ispin,d_part2,i_bitmask_gen),  &
            not(psi_det_generators(k,ispin,i_generator)) )
      enddo
    enddo
    if($do_double_excitations)then
     call $subroutine_diexc(psi_det_generators(1,1,i_generator),      &
         psi_det_generators(1,1,1),                                   &
         mask(1,1,d_hole1), mask(1,1,d_part1),                        &
         mask(1,1,d_hole2), mask(1,1,d_part2),                        &
         fock_diag_tmp, i_generator, iproc $params_post)
    endif
    if($do_mono_excitations)then
     call $subroutine_monoexc(psi_det_generators(1,1,i_generator),    &
         mask(1,1,s_hole ), mask(1,1,s_part ),                        &
         fock_diag_tmp, i_generator, iproc $params_post)
    endif
    call wall_time(wall_1)
    $printout_always
    if (wall_1 - wall_0 > 2.d0) then
        $printout_now
        wall_0 = wall_1
    endif
  enddo

  deallocate( mask, fock_diag_tmp )

  !$OMP PARALLEL DEFAULT(SHARED) &
  !$OMP PRIVATE(i_generator,wall_1,wall_0,ispin,k,mask,iproc,fock_diag_tmp) 
  call wall_time(wall_0)
  !$ iproc = omp_get_thread_num()
  allocate( mask(N_int,2,6), fock_diag_tmp(2,mo_tot_num+1) )
  !$OMP DO SCHEDULE(dynamic,1)
  do i_generator=nmax+1,N_det_generators
    $skip

    ! Compute diagonal of the Fock matrix
    call build_fock_tmp(fock_diag_tmp,psi_det_generators(1,1,i_generator),N_int)

    ! Create bit masks for holes and particles
    do ispin=1,2
      do k=1,N_int
        mask(k,ispin,s_hole) =                                      &
            iand(generators_bitmask(k,ispin,s_hole,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,s_part) =                                      &
            iand(generators_bitmask(k,ispin,s_part,i_bitmask_gen),  &
            not(psi_det_generators(k,ispin,i_generator)) )
        mask(k,ispin,d_hole1) =                                      &
            iand(generators_bitmask(k,ispin,d_hole1,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,d_part1) =                                      &
            iand(generators_bitmask(k,ispin,d_part1,i_bitmask_gen),  &
            not(psi_det_generators(k,ispin,i_generator)) )
        mask(k,ispin,d_hole2) =                                      &
            iand(generators_bitmask(k,ispin,d_hole2,i_bitmask_gen),  &
            psi_det_generators(k,ispin,i_generator) )
        mask(k,ispin,d_part2) =                                      &
            iand(generators_bitmask(k,ispin,d_part2,i_bitmask_gen),  &
            not (psi_det_generators(k,ispin,i_generator)) )
      enddo
    enddo

    if($do_double_excitations)then
      call $subroutine_diexc(psi_det_generators(1,1,i_generator),    &
        psi_det_generators(1,1,1),                                   &
        mask(1,1,d_hole1), mask(1,1,d_part1),                        &
        mask(1,1,d_hole2), mask(1,1,d_part2),                        &
        fock_diag_tmp, i_generator, iproc $params_post)
    endif
    if($do_mono_excitations)then
      call $subroutine_monoexc(psi_det_generators(1,1,i_generator),  &
        mask(1,1,s_hole ), mask(1,1,s_part ),                        &
        fock_diag_tmp, i_generator, iproc $params_post)
    endif
    !$ call omp_set_lock(lck)
    call wall_time(wall_1)
    $printout_always
    if (wall_1 - wall_0 > 2.d0) then
        $printout_now
        wall_0 = wall_1
    endif
    !$ call omp_unset_lock(lck)
  enddo
  !$OMP END DO 
  deallocate( mask, fock_diag_tmp )
  !$OMP END PARALLEL
  !$ call omp_destroy_lock(lck)

  $copy_buffer
  $generate_psi_guess
  
end