code: def elliot_function( signal, derivative=False ):
      
      s = 1 # steepness
      
      abs_signal = (1 + np.abs(signal * s))
      if derivative:
          return 0.5 * s / abs_signal**2
      else:
          # Return the activation signal
          return 0.5*(signal * s) / abs_signal + 0.5
docs: A fast approximation of sigmoid