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