как заставить iOpen срабатывать по OnCalculate ?

[Evgenii Sidorov]

К примеру такой пользовательский индикатор , проблема в том что при такой записи данные из BufferL отображаются единожды и больше не обновляются

//+------------------------------------------------------------------+
//|                                                         trio.mq4 |
//|                        Copyright 2017, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2017, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property strict
#property indicator_chart_window
#property indicator_buffers 1

#property indicator_color1 Blue
#property indicator_width1 2
#property indicator_style1 0

#property indicator_color2 Red
#property indicator_width2 2
#property indicator_style2 0


double BufferH[];
double BufferL[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexBuffer(0,BufferH);
   SetIndexStyle(0,DRAW_LINE);
  
   SetIndexBuffer(1,BufferL);
   SetIndexStyle(1,DRAW_LINE);
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[]
               
               
                )
               
   {

   for(int i =0; i<Bars; i++)
   {
      BufferH[i] = ((Open[i] + High[i] + Low[i] + Close[i])/4);
      BufferL[i] = (iOpen("EURUSD",0,i)+ iClose("EURUSD",0,i)/2);
   }
  

   return(rates_total);

   }