I tried the following code, iin the custom indicator of the bollingerband Where I want to forecast or predict the future one bollinger. See the code:
#property copyright "2009-2017, MetaQuotes Software Corp."
#property link "http://www.mql5.com"
#property description "Bollinger Bands"
#include <MovingAverages.mqh>
//---
#property indicator_chart_window
#property indicator_buffers 4
#property indicator_plots 3
#property indicator_type1 DRAW_LINE
#property indicator_color1 LightSeaGreen
#property indicator_type2 DRAW_LINE
#property indicator_color2 LightSeaGreen
#property indicator_type3 DRAW_LINE
#property indicator_color3 LightSeaGreen
#property indicator_label1 "Bands middle"
#property indicator_label2 "Bands upper"
#property indicator_label3 "Bands lower"
//--- input parametrs
input int InpBandsPeriod=21; // Period
input int InpBandsShift=0; // Shift
input double InpBandsDeviations=2.0; // Deviation
//--- global variables
int ExtBandsPeriod,ExtBandsShift;
double ExtBandsDeviations;
int ExtPlotBegin=0;
//---- indicator buffer
double ExtMLBuffer[];
double ExtTLBuffer[];
double ExtBLBuffer[];
double ExtStdDevBuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
void OnInit()
{
//--- check for input values
if(InpBandsPeriod<2)
{
ExtBandsPeriod=21;
printf("Incorrect value for input variable InpBandsPeriod=%d. Indicator will use value=%d for calculations.",InpBandsPeriod,ExtBandsPeriod);
}
else ExtBandsPeriod=InpBandsPeriod;
if(InpBandsShift<0)
{
ExtBandsShift=0;
printf("Incorrect value for input variable InpBandsShift=%d. Indicator will use value=%d for calculations.",InpBandsShift,ExtBandsShift);
}
else
ExtBandsShift=InpBandsShift;
if(InpBandsDeviations==0.0)
{
ExtBandsDeviations=2.0;
printf("Incorrect value for input variable InpBandsDeviations=%f. Indicator will use value=%f for calculations.",InpBandsDeviations,ExtBandsDeviations);
}
else ExtBandsDeviations=InpBandsDeviations;
//--- define buffers
SetIndexBuffer(0,ExtMLBuffer);
SetIndexBuffer(1,ExtTLBuffer);
SetIndexBuffer(2,ExtBLBuffer);
SetIndexBuffer(3,ExtStdDevBuffer,INDICATOR_CALCULATIONS);
//--- set index labels
PlotIndexSetString(0,PLOT_LABEL,"Bands("+string(ExtBandsPeriod)+") Middle");
PlotIndexSetString(1,PLOT_LABEL,"Bands("+string(ExtBandsPeriod)+") Upper");
PlotIndexSetString(2,PLOT_LABEL,"Bands("+string(ExtBandsPeriod)+") Lower");
//--- indicator name
IndicatorSetString(INDICATOR_SHORTNAME,"Bollinger Bands");
//--- indexes draw begin settings
ExtPlotBegin=ExtBandsPeriod;
PlotIndexSetInteger(0,PLOT_DRAW_BEGIN,ExtBandsPeriod);
PlotIndexSetInteger(1,PLOT_DRAW_BEGIN,ExtBandsPeriod);
PlotIndexSetInteger(2,PLOT_DRAW_BEGIN,ExtBandsPeriod);
//--- indexes shift settings
PlotIndexSetInteger(0,PLOT_SHIFT,ExtBandsShift);
PlotIndexSetInteger(1,PLOT_SHIFT,ExtBandsShift);
PlotIndexSetInteger(2,PLOT_SHIFT,ExtBandsShift);
//--- number of digits of indicator value
IndicatorSetInteger(INDICATOR_DIGITS,_Digits+1);
//---- OnInit done
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
const int prev_calculated,
const int begin,
const double &price[])
{
//--- variables
int pos;
//--- indexes draw begin settings, when we've recieved previous begin
if(ExtPlotBegin!=ExtBandsPeriod+1+begin)
{
ExtPlotBegin=ExtBandsPeriod+begin;
PlotIndexSetInteger(0,PLOT_DRAW_BEGIN,ExtPlotBegin);
PlotIndexSetInteger(1,PLOT_DRAW_BEGIN,ExtPlotBegin);
PlotIndexSetInteger(2,PLOT_DRAW_BEGIN,ExtPlotBegin);
}
//--- check for bars count
if(rates_total<ExtPlotBegin)
return(0);
//--- starting calculation
if(prev_calculated>1) pos=prev_calculated;
else pos=0;
//--- main cycle
for(int i=pos;i<rates_total+1 && !IsStopped();i++)
{
//--- middle line
ExtMLBuffer[i]=SimpleMA(i,ExtBandsPeriod,price);
//Print(ExtBandsPeriod);
//--- calculate and write down StdDev
ExtStdDevBuffer[i]=StdDev_Func(i,price,ExtMLBuffer,ExtBandsPeriod);
//--- upper line
ExtTLBuffer[i]=ExtMLBuffer[i]+ExtBandsDeviations*ExtStdDevBuffer[i];
//--- lower line
ExtBLBuffer[i]=ExtMLBuffer[i]-ExtBandsDeviations*ExtStdDevBuffer[i];
//---
}
//---- OnCalculate done. Return new prev_calculated.
return(rates_total + 1);
}
//+------------------------------------------------------------------+
//| Calculate Standard Deviation |
//+------------------------------------------------------------------+
double StdDev_Func(int position,const double &price[],const double &MAprice[],int period)
{
//--- variables
double StdDev_dTmp=0.0;
//--- check for position
if(position<period) return(StdDev_dTmp);
//--- calcualte StdDev
for(int i=0;i<period;i++) StdDev_dTmp+=MathPow(price[position-i]-MAprice[position],2);
StdDev_dTmp=MathSqrt(StdDev_dTmp/period);
//--- return calculated value
return(StdDev_dTmp);
}
But I am getting the following image when I applied the bollinger band.:
Please help me in creating a forecast for the bollinger using MQL5.
