Hi, Dick, I created a middle line, that I tested and it works. I have attached a chart image of the XAU Philadelpha Gold and Silver Index back in 2001 when It was going crazy.
I have also attached the modified BB code with the middle line plotted in blue.
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--- On Mon, 2/16/09, areehoi <areehoi@xxxxxxxxx> wrote:
What do I need to get a "middle Line"? Thanks
Dick H
--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko"
<groups@xxx> wrote:
>
> 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: mohany1@xxx
> To: amibroker@xxxxxxxxxxxxxxx
> Cc: amibroker@xxxxxxxxxxxxxxx ; amibroker@xxxxxxxxxxxxxxx
> 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();
>
------------------------------------
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