//+------------------------------------------------------------------+
//|                                              InverseReaction 1.2 |
//|                                              2013-2014 Erdem SEN |
//|                         http://login.mql5.com/en/users/erdogenes |
//+------------------------------------------------------------------+
#property copyright "Copyright 2013-2015, Erdem Sen"
#property version   "1.2"
#property link      "http://login.mql5.com/en/users/erdogenes"
//---
#property description "This indicator is based on the idea of that an unusual impact" 
#property description "in price changes will be adjusted by an inverse reaction."
#property description "The signal comes out when the price-change exceeds the possible"
#property description "volatility limits, then you can expect an inverse reaction."
//--- Indicator
#property indicator_separate_window
#property indicator_buffers 3
#property indicator_plots   3
//--- PriceChanges Plot
#property indicator_label1  "PriceChanges"
#property indicator_type1   DRAW_HISTOGRAM
#property indicator_color1  clrBlueViolet
//--- UpperLevel Plot 
#property indicator_label2  "UpperLevel"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrRed
//--- LowerLevel Plot
#property indicator_label3  "LowerLevel"
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrGreen
//--- ZeroLevel
#property indicator_level1 0
#property indicator_levelcolor clrBlueViolet
//---inputs
input int      MaPeriod    = 3;     // Moving average period
input double   Coefficient = 1.618; // Confidence coefficient
//--- global variables
int      drawstart,calcstart;
//--- buffers
double   PriceChanges[],u_DCL[],l_DCL[];
//+------------------------------------------------------------------+
//| Initialization function                                          |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- main buffers
   SetIndexBuffer(0,PriceChanges,INDICATOR_DATA);
   SetIndexBuffer(1,u_DCL,INDICATOR_DATA);
   SetIndexBuffer(2,l_DCL,INDICATOR_DATA);
//--- determine the start point for plotting
   drawstart=MaPeriod-1;
   PlotIndexSetInteger(0,PLOT_DRAW_BEGIN,drawstart);
   PlotIndexSetInteger(1,PLOT_DRAW_BEGIN,drawstart);
   PlotIndexSetInteger(2,PLOT_DRAW_BEGIN,drawstart);
//--- set a shortname
   string name=StringFormat("InverseReaction (%d, %.3f)",MaPeriod,Coefficient);
   IndicatorSetString(INDICATOR_SHORTNAME,name);
//--- set digits for vertical axis
   IndicatorSetInteger(INDICATOR_DIGITS,_Digits);
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| 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 avoiding recalculation
   if(prev_calculated>rates_total || prev_calculated<=0) calcstart=0;
   else calcstart=prev_calculated-1;
//--- check if there are enough bars
   if(calcstart==0 && rates_total<MaPeriod)
     {
      Print("Sorry!!, there are not enough bars. Download more historical data and retry");
      return(0);
     }
//--- calculate the buffers
   for(int i=calcstart;i<rates_total;i++)
     {
      PriceChanges[i]=(close[i]-open[i]);
      u_DCL[i]= DynamicConfidenceLevel(i,MaPeriod,Coefficient,PriceChanges);
      l_DCL[i]= -u_DCL[i];
     }
//---
   return(rates_total);
  }
/*---Dynamic Confidence Level (DCL)----------------------------------+

   For stationary series with zero mean (like price changes) DCL can be calculated as
      
         DCL = Multiplier * MovingAverage(AbsoluteChanges)

   Just for example, when we use Golden Ratio as multiplier, with the perfect 
   conditions of normality, it gives us nearly 80% confidence levels:

         StandardDeviation = Sqrt(Pi/2) * Mean(Abs(Changes))
         GoldenRatio ~= z_%80 * Sqrt(Pi/2)
         DCL(z_%80) ~= GoldenRatio * MovingAverage(Abs(Price Changes))
   
   With large numbers of MovingAverage period, DCL aproximates to a static confidence 
   level. However, the system is dynamic and memory is very short for such economic 
   behaviors, so it is set with a small number (3 as default). Plus, considering the 
   HEAVY-TAIL problem, small period values will relatively response better!!!!

*/
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
double DynamicConfidenceLevel(const int position,const int period,const double coef,const double &price[])
  {
   double result=0.0;
   if(position>=period-1 && period>0)
     {
      for(int i=0;i<period;i++) result+=fabs(price[position-i]);
      result /= period;
      result *= coef;
     }
   return(result);
  }
//-------------------------------------------------------------------