subroutine form_taus_nc(t1,t2,taus)

! Form tau in CCSD

  implicit none

! Input variables

  double precision,intent(in)   :: t1(spin_occ_num,spin_vir_num)
  double precision,intent(in)   :: t2(spin_occ_num,spin_occ_num,spin_vir_num,spin_vir_num)

! Local variables

  integer                       :: i,j,k,l
  integer                       :: a,b,c,d

! Output variables

  double precision,intent(out)  :: taus(spin_occ_num,spin_occ_num,spin_vir_num,spin_vir_num)

  do b=1,spin_vir_num
   do a=1,spin_vir_num
    do j=1,spin_occ_num
     do i=1,spin_occ_num

          taus(i,j,a,b) = t2(i,j,a,b) + 0.5d0*(t1(i,a)*t1(j,b) - t1(i,b)*t1(j,a))

        enddo
      enddo
    enddo
  enddo

end subroutine form_taus_nc