code: def QA_indicator_DDI(DataFrame, N=13, N1=26, M=1, M1=5):
      
  
      H = DataFrame['high']
      L = DataFrame['low']
      DMZ = IF((H + L) > (REF(H, 1) + REF(L, 1)), 
               MAX(ABS(H - REF(H, 1)), ABS(L - REF(L, 1))), 0)
      DMF = IF((H + L) < (REF(H, 1) + REF(L, 1)),
               MAX(ABS(H - REF(H, 1)), ABS(L - REF(L, 1))), 0)
      DIZ = SUM(DMZ, N) / (SUM(DMZ, N) + SUM(DMF, N))
      DIF = SUM(DMF, N) / (SUM(DMF, N) + SUM(DMZ, N))
      ddi = DIZ - DIF
      ADDI = SMA(ddi, N1, M)
      AD = MA(ADDI, M1)
      DICT = {'DDI': ddi, 'ADDI': ADDI, 'AD': AD}
  
      return pd.DataFrame(DICT)
docs: '方向标准离差指数'
      分析DDI柱状线，由红变绿(正变负)，卖出信号参考；由绿变红，买入信号参考。