- December 3, 2013
- Posted by: Forex Wiki Team
- Category: FX Ind
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Author: | MetaQuotes (2005.12.07 11:30) | ||
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Envelopes Technical Indicator is formed with two Moving Averages one of which is shifted upward and another one is shifted downward. The selection of optimum relative number of band margins shifting is determined with the market volatility: the higher the latter is, the stronger the shift is.
Envelopes define the upper and the lower margins of the price range. Signal to sell appears when the price reaches the upper margin of the band; signal to buy appears when the price reaches the lower margin. The logic behind envelopes is that overzealous buyers and sellers push the price to the extremes (i.e., the upper and lower bands), at which point the prices often stabilize by moving to more realistic levels. This is similar to the interpretation of Bollinger Bands. Calculation Where: Technical Indicator DescriptionFull description of Env is available in the Technical analysis: Envelopes |
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buccas13:
Hi, Thanks for this developing this indicator and sharing it. Is it possible to change the MA method to Smoothed or Linear weighted or Exponential? You could call any of the Ma functions from this code sample, to use in the Envelopes indicator. //+------------------------------------------------------------------+ //| Custom Moving Average.mq4 | //| Copyright © 2004, MetaQuotes Software Corp. | //| http://www.metaquotes.net/ | //+------------------------------------------------------------------+ #property copyright "Copyright © 2004, MetaQuotes Software Corp." #property link "http://www.metaquotes.net/" #property indicator_chart_window #property indicator_buffers 1 #property indicator_color1 Red //---- indicator parameters extern int MA_Period=13; extern int MA_Shift=0; extern int MA_Method=0; //---- indicator buffers double ExtMapBuffer[]; //---- int ExtCountedBars=0; //+------------------------------------------------------------------+ //| Custom indicator initialization function | //+------------------------------------------------------------------+ int init() { int draw_begin; string short_name; //---- drawing settings SetIndexStyle(0,DRAW_LINE); SetIndexShift(0,MA_Shift); IndicatorDigits(MarketInfo(Symbol(),MODE_DIGITS)); if(MA_Period<2) MA_Period=13; draw_begin=MA_Period-1; //---- indicator short name switch(MA_Method) { case 1 : short_name="EMA("; draw_begin=0; break; case 2 : short_name="SMMA("; break; case 3 : short_name="LWMA("; break; default : MA_Method=0; short_name="SMA("; } IndicatorShortName(short_name+MA_Period+")"); SetIndexDrawBegin(0,draw_begin); //---- indicator buffers mapping SetIndexBuffer(0,ExtMapBuffer); //---- initialization done return(0); } //+------------------------------------------------------------------+ //| | //+------------------------------------------------------------------+ int start() { if(Bars<=MA_Period) return(0); ExtCountedBars=IndicatorCounted(); //---- check for possible errors if (ExtCountedBars<0) return(-1); //---- last counted bar will be recounted if (ExtCountedBars>0) ExtCountedBars--; //---- switch(MA_Method) { case 0 : sma(); break; case 1 : ema(); break; case 2 : smma(); break; case 3 : lwma(); } //---- done return(0); } //+------------------------------------------------------------------+ //| Simple Moving Average | //+------------------------------------------------------------------+ void sma() { double sum=0; int i,pos=Bars-ExtCountedBars-1; //---- initial accumulation if(pos<MA_Period) pos=MA_Period; for(i=1;i<MA_Period;i++,pos--) sum+=Close[pos]; //---- main calculation loop while(pos>=0) { sum+=Close[pos]; ExtMapBuffer[pos]=sum/MA_Period; sum-=Close[pos+MA_Period-1]; pos--; } //---- zero initial bars if(ExtCountedBars<1) for(i=1;i<MA_Period;i++) ExtMapBuffer[Bars-i]=0; } //+------------------------------------------------------------------+ //| Exponential Moving Average | //+------------------------------------------------------------------+ void ema() { double pr=2.0/(MA_Period+1); int pos=Bars-2; if(ExtCountedBars>2) pos=Bars-ExtCountedBars-1; //---- main calculation loop while(pos>=0) { if(pos==Bars-2) ExtMapBuffer[pos+1]=Close[pos+1]; ExtMapBuffer[pos]=Close[pos]*pr+ExtMapBuffer[pos+1]*(1-pr); pos--; } } //+------------------------------------------------------------------+ //| Smoothed Moving Average | //+------------------------------------------------------------------+ void smma() { double sum=0; int i,k,pos=Bars-ExtCountedBars+1; //---- main calculation loop pos=Bars-MA_Period; if(pos>Bars-ExtCountedBars) pos=Bars-ExtCountedBars; while(pos>=0) { if(pos==Bars-MA_Period) { //---- initial accumulation for(i=0,k=pos;i<MA_Period;i++,k++) { sum+=Close[k]; //---- zero initial bars ExtMapBuffer[k]=0; } } else sum=ExtMapBuffer[pos+1]*(MA_Period-1)+Close[pos]; ExtMapBuffer[pos]=sum/MA_Period; pos--; } } //+------------------------------------------------------------------+ //| Linear Weighted Moving Average | //+------------------------------------------------------------------+ void lwma() { double sum=0.0,lsum=0.0; double price; int i,weight=0,pos=Bars-ExtCountedBars-1; //---- initial accumulation if(pos<MA_Period) pos=MA_Period; for(i=1;i<=MA_Period;i++,pos--) { price=Close[pos]; sum+=price*i; lsum+=price; weight+=i; } //---- main calculation loop pos++; i=pos+MA_Period; while(pos>=0) { ExtMapBuffer[pos]=sum/weight; if(pos==0) break; pos--; i--; price=Close[pos]; sum=sum-lsum+price*MA_Period; lsum-=Close[i]; lsum+=price; } //---- zero initial bars if(ExtCountedBars<1) for(i=1;i<MA_Period;i++) ExtMapBuffer[Bars-i]=0; } //+------------------------------------------------------------------+ 02.01.2012 22:29 AmIBroke
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