anchor.diff:             -Uc,  0,   0,  V, &
                0, Uf,   V,  0 /)
   
  -        call write_data(0.0_dp,0.3_dp)
  -      end do
  +        call write_data(0.25_dp*j,0.1_dp)
  +!       end do
       end do
     end do
   
  
positive.code: 
    do i=0,4
      do j=0,4
        do k=0,4
  
  ! Set experimental data
          t   = 1_dp
  
negative.code:         x0  = 0.02_dp
          epsf= 0.1_dp*x0
          Uc  = 0.25_dp*i
          Uf  = 0.25_dp*i
          V   = 0.1_dp
  
  ! Set up matrix as an array of size 16
          Gkinv = (/ complex(dp) :: &
  