Re: [amibroker] Better Bollinger Bands

[Tomasz Janeczko]

Hello,

Replace lines like that:

mt = alpha*C+(1-alpha)*(if(Cum(1)<pds,C,PREV));

with AFL equivalent (simpler):

mt = AMA( C, alpha );

Any other statement involving PREV the same way.

Final result:

pds=Param("Periods",20,2,200); 
sd=Param("Standard Deviations",2, 0.01,10); 
alpha=2/(pds+1); 
mt=AMA( C, alpha ); 
ut=AMA( mt, alpha ); 
dt=((2-alpha)*mt-ut)/(1-alpha); 
mt2=AMA(abs(C-dt), alpha ); 
ut2=AMA(mt2,alpha ); 
dt2=((2-alpha)*mt2-ut2)/(1-alpha); 
but=dt+sd*dt2; 
blt=dt-sd*dt2; 

Plot( C, "Price", colorBlack, styleCandle ); 
Plot( but, "Upper band", colorRed ); 
Plot( blt, "Lower band", colorRed ); 



Best regards,
Tomasz Janeczko
amibroker.com
  ----- Original Message ----- 
  From: moha...@verizon.net 
  To: amibroker@yahoogroups.com 
  Cc: amibroker@yahoogroups.com ; amibroker@yahoogroups.com 
  Sent: Sunday, February 15, 2009 3:37 AM
  Subject: [amibroker] Better Bollinger Bands


  Someone was asking for this afl. I got around to translating. Enjoy.


  Now, if only someone can teach me , really how to make money !!!


  /*
  Better Bollinger Bands I


  pds:=Input("Periods",2,200,20);
  sd:=Input("Standard Deviations",.01,10,2);
  alpha:=2/(pds+1);
  mt:=alpha*C+(1-alpha)*(if(Cum(1)<pds,C,PREV));
  ut:=alpha*mt+(1-alpha)*(if(Cum(1)<pds,C,PREV));
  dt:=((2-alpha)*mt-ut)/(1-alpha);
  mt2:=alpha*abs(C-dt)+(1-alpha)*PREV;
  ut2:=alpha*mt2+(1-alpha)*PREV;
  dt2:=((2-alpha)*mt2-ut2)/(1-alpha);
  but:=dt+sd*dt2;
  blt:=dt-sd*dt2;
  dt;
  but;
  blt


  //------------  easy language -----------


  inputs:
  lookback(20),
  mult(2);


  vars:
  alpha(0),
  mt(0),
  ut(0),
  dt(0),
  mt2(0),
  ut2(0),
  dt2(0),
  but(0),
  blt(0);


  alpha = 2 / (lookback + 1);
  mt = alpha * close + (1 - alpha) * mt;
  ut = alpha * mt + (1 - alpha) * ut;
  dt = ((2 - alpha) * mt - ut) / (1 - alpha);
  mt2 = alpha * absvalue(close - dt) + (1 - alpha) * mt2;
  ut2 = alpha * mt2 + (1 - alpha) * ut2;
  dt2 = ((2 - alpha) * mt2 - ut2) / (1 - alpha);
  but = dt + mult * dt2;
  blt = dt - mult * dt2;
  plot1(dt,"CenterB");
  plot2(but,"UpperB");
  plot3(blt,"LowerB");
  */


  _SECTION_BEGIN("Better Bollinger Bands");
  pds = Param("Periods",2,1,200,1);
  SD = Param("sd",3,0.01,5,0.01);
  ALPHA = 2/(PDS+1);
  mt = AMA(C, alpha);
  ut = AMA(mt, alpha);
  dt = ((2 - alpha) * mt - ut) / (1 - alpha);
  //mt2 = alpha * absvalue(Close - dt) + (1 - alpha) * mt2;
  mt2 = AMA(abs(C - dt), alpha);


  ut2 = AMA( mt2 , alpha) ;
  dt2 = ((2 - alpha) * mt2 - ut2) / (1 - alpha);


  but = dt + sd * dt2;
  blt = dt - sd * dt2;


  Plot(but,"Upper Band", colorRed, styleLine);
  Plot(dt,"Cente Band", colorBlue, styleLine);
  Plot(blt,"Lower Band", colorBrightGreen, styleLine);


  _SECTION_END();