anchor.diff:          select case(opt_target)
           case('absolute','abs')
              rmsd1 = rmsd_E + rmsd_dE
  -        case('relative','rel')  
  +        case('relative','rel')
              rmsd1 = rmsd_err + rmsd_dE
              bias  = dmean_E
  -        case('differences','diff')  
  +        case('differences','diff')
              rmsd1 = rmsd_dE
              bias  = dmean_E
           end select
  
positive.code:     double precision,                    intent(in)  :: r0, r1
      integer,                             intent(in)  :: nr
      double precision, dimension(nr),     intent(out) :: p
      
      integer, parameter :: u_hist = 50
  
      double precision :: r, dr
  
negative.code:   !--------------------------------------------------------------------!
  
    subroutine init_csplines_fit()
  
      implicit none
  
      ! restarting previous fit?
  