code: def NRM(f,a,b,best):
      WARN = True    # Warn, rather than stop if I encounter a NaN...
      
      if float(f)==0:
          print('ERROR: NRM: f==0.')
      if not WARN : sys.exit()
      m = (old_div(float(best),float(f))) * TRM(f,a,b)
      return float(m)
docs: Calculate NRM expected lab field and estimated ancient field
      NRM(blab,best)= (best/blab)*TRM(blab)