Corr Wilder EMA

ÿþ//------------------------------------------------------------------

#property copyright   "© mladen, 2019"

#property link        "mladenfx@gmail.com"

#property description "Corrected double smoothed Wilder's EMA"

//------------------------------------------------------------------

#property indicator_chart_window

#property indicator_buffers 5

#property indicator_plots   2

#property indicator_label1  "Corrected average original"

#property indicator_type1   DRAW_COLOR_LINE

#property indicator_color1  clrSilver,clrMediumSeaGreen,clrOrangeRed

#property indicator_label2  "Corrected average "

#property indicator_type2   DRAW_COLOR_LINE

#property indicator_color2  clrSilver,clrMediumSeaGreen,clrOrangeRed

#property indicator_width2  3



//

//---

//



input int                inpPeriod           = 14;             // Average period

input ENUM_APPLIED_PRICE inpPrice            = PRICE_CLOSE;    // Price

input int                inpCorrectionPeriod =  0;             // "Correction" period (<0 no correction,0 to 1 same as average)



//

//---

//



double val[],valc[],avg[],avgc[],avgw[];

int  ª_maPeriod,ª_corrPeriod; 

double _alpha;



//------------------------------------------------------------------

//

//------------------------------------------------------------------



int OnInit()

{

   //

   //---

   //

         SetIndexBuffer(0,avg ,INDICATOR_DATA);

         SetIndexBuffer(1,avgc,INDICATOR_COLOR_INDEX);

         SetIndexBuffer(2,val ,INDICATOR_DATA);

         SetIndexBuffer(3,valc,INDICATOR_COLOR_INDEX);

         SetIndexBuffer(4,avgw,INDICATOR_CALCULATIONS);

         

         ª_corrPeriod = (inpCorrectionPeriod>0) ? inpCorrectionPeriod : (inpCorrectionPeriod<0) ? 0 : inpPeriod ;

         ª_maPeriod   = (inpPeriod>1) ? inpPeriod : 1;

            _alpha = 1.0 /MathSqrt(ª_maPeriod);

   //

   //---

   //      

   IndicatorSetString(INDICATOR_SHORTNAME,"\"Corrected\" Wilder\'s EMA ("+(string)inpPeriod+","+(string)inpCorrectionPeriod+")");

   return(0);

}



//------------------------------------------------------------------

// Custom indicator iteration function

//------------------------------------------------------------------

//

//---

//



#define _setPrice(_priceType,_target,_index) \

   { \

   switch(_priceType) \

   { \

      case PRICE_CLOSE:    _target = close[_index];                                              break; \

      case PRICE_OPEN:     _target = open[_index];                                               break; \

      case PRICE_HIGH:     _target = high[_index];                                               break; \

      case PRICE_LOW:      _target = low[_index];                                                break; \

      case PRICE_MEDIAN:   _target = (high[_index]+low[_index])/2.0;                             break; \

      case PRICE_TYPICAL:  _target = (high[_index]+low[_index]+close[_index])/3.0;               break; \

      case PRICE_WEIGHTED: _target = (high[_index]+low[_index]+close[_index]+close[_index])/4.0; break; \

      default : _target = 0; \

   }}

//

//---

//



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[])

{ 

   int i= prev_calculated-1; if (i<0) i=0; for (; i<rates_total && !_StopFlag; i++)

   {

      double _price; _setPrice(inpPrice,_price,i);

      if (i>0)

      {

         avgw[i] = avgw[i-1] + _alpha*(_price-avgw[i-1]);

         avg[i]  = avg[i-1]  + _alpha*(avgw[i]-avg[i-1]);

      }

      else avg[i]  = avgw[i] = _price;

           val[i]  = iCorrMa(_price,avg[i],ª_corrPeriod,i,rates_total);

           avgc[i] = valc[i] = (avg[i]>val[i]) ? 1 : (avg[i]<val[i]) ? 2 : 0;

   }

   return(i);

}



//------------------------------------------------------------------

// Custom function(s)

//------------------------------------------------------------------

//

//

//



double iCorrMa(double price, double average, int period, int i, int bars, int instance=0)

{

   #define ¤ instance

   #define _functionInstances 1

      

      struct sCorrMaStruct

         {

            double corrected;

            double price;

            double price2;

            double summ;

            double summ2;

         };

      static sCorrMaStruct m_array[][_functionInstances];

      static int m_arraySize=0;

             if (m_arraySize<bars) { m_arraySize = ArrayResize(m_array,bars+500); if (m_arraySize<=bars) return(0); }

      

      //

      //---

      //

      

      m_array[i][¤].price  = price;

      m_array[i][¤].price2 = price*price;

      if (i>period)

            {

               m_array[i][¤].summ  = m_array[i-1][¤].summ +price               -m_array[i-period][¤].price;

               m_array[i][¤].summ2 = m_array[i-1][¤].summ2+m_array[i][¤].price2-m_array[i-period][¤].price2;

            }

      else  {

               m_array[i][¤].summ  = m_array[i][¤].price;

               m_array[i][¤].summ2 = m_array[i][¤].price2; 

               for(int k=1; k<period && i>=k; k++) 

               {

                  m_array[i][¤].summ  += m_array[i-k][¤].price; 

                  m_array[i][¤].summ2 += m_array[i-k][¤].price2; 

               }                  

            }         



      //

      //---

      //

      

      if (i>0) 

      {

         double v1 = (m_array[i][¤].summ2-m_array[i][¤].summ*m_array[i][¤].summ/(double)period)/(double)period;

         double v2 = (m_array[i-1][¤].corrected-average)*(m_array[i-1][¤].corrected-average);

         double c  = (v2<v1 || v2==0) ? 0 : 1.0-v1/v2;

            m_array[i][¤].corrected = m_array[i-1][¤].corrected + c*(average-m_array[i-1][¤].corrected);

      }

      else m_array[i][¤].corrected = average;

   return (m_array[i][¤].corrected);

   

   //

   //---

   //

   

   #undef ¤ #undef _functionInstances

}

//------------------------------------------------------------------