anchor.diff:       do j = jlo-3, jhi+3
           do i = ilo-3, ihi+3
   
  +           ! test whether we are at an extremum
              test = (a(i+1,j) - a(i,j))*(a(i,j) - a(i-1,j))
   
              if (test > 0.0d0) then
  
positive.code: !f2py intent(in) :: a
  !f2py intent(out) :: lda
  
  ! call this as: lda = reconstruction_f.nolimit(1,a,qx,qy,ng)
  
    integer :: ilo, ihi, jlo, jhi
    integer :: nx, ny
  
negative.code:      do j = jlo-3, jhi+3
          do i = ilo-3, ihi+3
  
             ! test whether we are at an extremum
             test = (a(i,j+1) - a(i,j))*(a(i,j) - a(i,j-1))
  
             if (test > 0.0d0) then
  