ボリンジャーバンドのMA種別を変更する
EMAを使っている人は、EMAベースのボリンジャーバンドってどうなるんだろうと考えたことが1度はあるのかもしれない。
ボリンジャーバンドはSMAベースのインジケータで、EMAベースのバンドを表示することは出来ない。
この理由は、ボリンジャーバンドが使っている標準偏差にある。
標準偏差は、計算の中で対象のデータと平均の差を求めており、ボリンジャーバンドではこの平均の値としてSMAを用いている。
仮にEMAをボリンジャーバンドのMA種別に使用した場合は、もはやそれは標準偏差ではなくなってしまう。
とは言え、やれないことはないのでやってみる。
MT4、MT5ともにMetaEditorにボリンジャーバンドのファイルがあるのでそれを編集する。
//+------------------------------------------------------------------+
//| Bands.mq4 |
//| Copyright 2005-2014, MetaQuotes Software Corp. |
//| http://www.mql4.com |
//+------------------------------------------------------------------+
#property copyright "2005-2014, MetaQuotes Software Corp."
#property link "http://www.mql4.com"
#property description "Bollinger Bands"
#property strict
#include <MovingAverages.mqh>
#property indicator_chart_window
#property indicator_buffers 3
#property indicator_color1 LightSeaGreen
#property indicator_color2 LightSeaGreen
#property indicator_color3 LightSeaGreen
//--- indicator parameters
input int InpBandsPeriod=20; // Bands Period
input int InpBandsShift=0; // Bands Shift
input double InpBandsDeviations=2.0; // Bands Deviations
//--- buffers
double ExtMovingBuffer[];
double ExtUpperBuffer[];
double ExtLowerBuffer[];
double ExtStdDevBuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int OnInit(void)
{
//--- 1 additional buffer used for counting.
IndicatorBuffers(4);
IndicatorDigits(Digits);
//--- middle line
SetIndexStyle(0,DRAW_LINE);
SetIndexBuffer(0,ExtMovingBuffer);
SetIndexShift(0,InpBandsShift);
SetIndexLabel(0,"Bands SMA");
//--- upper band
SetIndexStyle(1,DRAW_LINE);
SetIndexBuffer(1,ExtUpperBuffer);
SetIndexShift(1,InpBandsShift);
SetIndexLabel(1,"Bands Upper");
//--- lower band
SetIndexStyle(2,DRAW_LINE);
SetIndexBuffer(2,ExtLowerBuffer);
SetIndexShift(2,InpBandsShift);
SetIndexLabel(2,"Bands Lower");
//--- work buffer
SetIndexBuffer(3,ExtStdDevBuffer);
//--- check for input parameter
if(InpBandsPeriod<=0)
{
Print("Wrong input parameter Bands Period=",InpBandsPeriod);
return(INIT_FAILED);
}
//---
SetIndexDrawBegin(0,InpBandsPeriod+InpBandsShift);
SetIndexDrawBegin(1,InpBandsPeriod+InpBandsShift);
SetIndexDrawBegin(2,InpBandsPeriod+InpBandsShift);
//--- initialization done
return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Bollinger Bands |
//+------------------------------------------------------------------+
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,pos;
//---
if(rates_total<=InpBandsPeriod || InpBandsPeriod<=0)
return(0);
//--- counting from 0 to rates_total
ArraySetAsSeries(ExtMovingBuffer,false);
ArraySetAsSeries(ExtUpperBuffer,false);
ArraySetAsSeries(ExtLowerBuffer,false);
ArraySetAsSeries(ExtStdDevBuffer,false);
ArraySetAsSeries(close,false);
//--- initial zero
if(prev_calculated<1)
{
for(i=0; i<InpBandsPeriod; i++)
{
ExtMovingBuffer[i]=EMPTY_VALUE;
ExtUpperBuffer[i]=EMPTY_VALUE;
ExtLowerBuffer[i]=EMPTY_VALUE;
}
}
//--- starting calculation
if(prev_calculated>1)
pos=prev_calculated-1;
else
pos=0;
//--- main cycle
for(i=pos; i<rates_total && !IsStopped(); i++)
{
//--- middle line
if(i==0) {
ExtMovingBuffer[i]=ExponentialMA(i,InpBandsPeriod,close[i],close);
} else {
ExtMovingBuffer[i]=ExponentialMA(i,InpBandsPeriod,ExtMovingBuffer[i-1],close);
}
//--- calculate and write down StdDev
ExtStdDevBuffer[i]=StdDev_Func(i,close,ExtMovingBuffer,InpBandsPeriod);
//--- upper line
ExtUpperBuffer[i]=ExtMovingBuffer[i]+InpBandsDeviations*ExtStdDevBuffer[i];
//--- lower line
ExtLowerBuffer[i]=ExtMovingBuffer[i]-InpBandsDeviations*ExtStdDevBuffer[i];
//---
}
//---- OnCalculate done. Return new prev_calculated.
return(rates_total);
}
//+------------------------------------------------------------------+
//| 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)
{
//--- 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);
}
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+
//| BB.mq5 |
//| Copyright 2009-2020, MetaQuotes Software Corp. |
//| http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2009-2020, 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=20; // 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=20;
PrintFormat("Incorrect value for input variable InpBandsPeriod=%d. Indicator will use value=%d for calculations.",InpBandsPeriod,ExtBandsPeriod);
}
else
ExtBandsPeriod=InpBandsPeriod;
if(InpBandsShift<0)
{
ExtBandsShift=0;
PrintFormat("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;
PrintFormat("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-1;
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);
}
//+------------------------------------------------------------------+
//| Bollinger Bands |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
const int prev_calculated,
const int begin,
const double &price[])
{
if(rates_total<ExtPlotBegin)
return(0);
//--- indexes draw begin settings, when we've recieved previous begin
if(ExtPlotBegin!=ExtBandsPeriod+begin)
{
ExtPlotBegin=ExtBandsPeriod+begin;
PlotIndexSetInteger(0,PLOT_DRAW_BEGIN,ExtPlotBegin);
PlotIndexSetInteger(1,PLOT_DRAW_BEGIN,ExtPlotBegin);
PlotIndexSetInteger(2,PLOT_DRAW_BEGIN,ExtPlotBegin);
}
//--- starting calculation
int pos;
if(prev_calculated>1)
pos=prev_calculated-1;
else
pos=0;
//--- main cycle
for(int i=pos; i<rates_total && !IsStopped(); i++)
{
//--- middle line
if(i==0) {
ExtMLBuffer[i]=ExponentialMA(i,InpBandsPeriod,price[i],price);
} else {
ExtMLBuffer[i]=ExponentialMA(i,InpBandsPeriod,ExtMLBuffer[i-1],price);
}
//--- 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);
}
//+------------------------------------------------------------------+
//| Calculate Standard Deviation |
//+------------------------------------------------------------------+
double StdDev_Func(const int position,const double &price[],const double &ma_price[],const int period)
{
double std_dev=0.0;
//--- calcualte StdDev
if(position>=period)
{
for(int i=0; i<period; i++)
std_dev+=MathPow(price[position-i]-ma_price[position],2.0);
std_dev=MathSqrt(std_dev/period);
}
//--- return calculated value
return(std_dev);
}
//+------------------------------------------------------------------+
