The last best-fit parabolic

TSOKAKIS · Feb 17, 2005

Quote from Dynomitedoll:

Hi ,
I would like to ask what would happen to the parabolic when an unusual trade took place like the one as shown in the attachment.
Would the parabolic adjust itself in the subsequent candles automatically? The upper chart is perc>20 and the bottom is perc<20.
-- N!!
More...

Natasha,
The ascending best-fit parabolic begins from the last trough and is the best-fit 2nd degree line between all the Lows, from the trough till now. An extreme low may
a. affect substantially the parabolic coefficient
b. define a new trough
It depends on the perc you use.

As for your second question, the answer is positive. The whole parabolic line is redrawn every new day.

TSOKAKIS · Feb 17, 2005

Quote from TSOKAKIS:

Natasha,
The ascending best-fit parabolic begins from the last trough and is the best-fit 2nd degree line between all the Lows, from the trough till now. An extreme low may
a. affect substantially the parabolic coefficient
b. define a new trough
It depends on the perc you use.

As for your second question, the answer is positive. The whole parabolic line is redrawn every new day.
More...

Take a look at the
http://finance.groups.yahoo.com/group/amibroker/message/69624
It gives the historical best-fit parabolics. Move your cursor from bar to bar and see how the whole line changes every new day.

forextrades · Feb 28, 2005

Does anyone have the code for this indocator for Metastock? TIA.

TSOKAKIS · Mar 1, 2005

Quote from forextrades:

Does anyone have the code for this indocator for Metastock? TIA.
More...

I do not know MS language.
Note that the software should support "for-next" loops, in order to translate the basic idea of the best-fit parabolic.

kiwi_trader · Aug 5, 2005

Tsokakis,

I've been asked if I could run up your "better parabolic" for sierrachart but I confess that the code below is double dutch to me -- too many constructs I dont understand.

Is there a plain english / c / basic / easylanguage version of it anywhere? Or if you are feeling bored could you advise the basic core of it yourself?

Thanks

Quote from TSOKAKIS:

The following AFL code will plot the best-fit parabolic from the last Peak[or Trough] till now.
The boundary parabolas will also be plotted, in order to ensure the loop range.

Plot(C,"C",1,64);
perc=3;//sensitivity calibration
x=BarIndex();xx=LastValue(x);
t1=LastValue(ValueWhen(PeakBars(H,perc)==0,x));
H1=LastValue(ValueWhen(PeakBars(H,perc)==0,H));
t11=LastValue(ValueWhen(TroughBars(L,perc)==0,x));
H11=LastValue(ValueWhen(TroughBars(L,perc)==0,L));
g=t1>t11;
shape=IIf(g,shapeDownArrow*(x==t1),shapeUpArrow*(x==t11));
Color=IIf(g,colorRed,colorBrightGreen);
PlotShapes(shape,color);
t=IIf(g,x-t1,x-t11);
diff1=IIf(g,H1*(xx-t1),H11*(xx-t11));
Lma=LastValue(MA(C,50));
f1=0;f2=IIf(Lma<100,1,0)+3*int(log10(Lma));
fa=0;fb=0;step=f2/100;
for(f=f1;f<f2;f=f+step)
{
parabolic=IIf(g,H1-f*t^2,H11+f*t^2);
S1=LastValue(Sum(abs(parabolic-H),xx-t1));
S11=LastValue(Sum(abs(parabolic-L),xx-t11));
diff=IIf(g,S1,S11);
if(diff<diff1)
{
diff1=diff;fa=f;
}
}
for(f=Max(fa-step,0);f<fa+step;f=f+0.01*step)
{
parabolic=IIf(g,H1-f*t^2,H11+f*t^2);
S1=LastValue(Sum(abs(parabolic-H),xx-t1));
S11=LastValue(Sum(abs(parabolic-L),xx-t11));

diff=IIf(g,S1,S11);
if(diff<diff1)
{
diff1=diff;fb=f;
}
}
p=IIf(g,H1-fb*t^2,H11+fb*t^2);
p0=IIf(g,H1-f2*t^2,H11+f2*t^2);
p0=IIf(p0>LLV(L,200) AND p0<HHV(H,200),p0,Null);
p1=IIf(g,H1,H11);
Plot(IIf(x>=Max(t1,t11),p,-1e10),"",color,8);
Plot(IIf(x>=Max(t1,t11),p0,-1e10),"",color+1,1);
Plot(IIf(x>=Max(t1,t11),p1,-1e10),"",color+1,1);
Title=Name()+", "+WriteIf(t1>t11,"f_desc","f_asc")+"="+WriteVal(fb,1.4);//+"[f2="+WriteVal(f2)+",step="+WriteVal(step);
GraphXSpace=3;
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nononsense · Aug 5, 2005

Quote from kiwi_trader:

Tsokakis,

I've been asked if I could run up your "better parabolic" for sierrachart but I confess that the code below is double dutch to me -- too many constructs I dont understand.

Is there a plain english / c / basic / easylanguage version of it anywhere? Or if you are feeling bored could you advise the basic core of it yourself?

Thanks
More...

I wondered a long time already what is meant by the 'last best-fit parabolic'.
Is this the one that truly makes the most money for you or is this an exercise in visually pleasing esthetics?

kut2k2 · Aug 5, 2005

Quote from nononsense:

I wondered a long time already what is meant by the 'last best-fit parabolic'.
Is this the one that truly makes the most money for you or is this an exercise in visually pleasing esthetics?
More...

I hear you. What's so special about the 'best' quadratic? Why not the 'best' cubic, or the 'best' quintic?

Curve-fitting can be good or bad. I suspect this is [Xander Harris]not of the good[/Xander Harris].

ZiGenov · Aug 5, 2005

If you don't understand the math and the great job Dimitris Tsokakis is doing in TA, just shut up and don't contaminate this excellent thread with your stupid remarks.

Morons!

kut2k2 · Aug 5, 2005

Quote from ZiGenov:

If you don't understand the math and the great job Dimitris Tsokakis is doing in TA, just shut up and don't contaminate this excellent thread with your stupid remarks.

Morons!
More...

I understand the math just fine. More importantly, I know better than to force the data to fit my "pet" theory, dumbass.

JackR · Aug 5, 2005

Quote from kiwi_trader:

Tsokakis,

Is there a plain english / c / basic / easylanguage version of it anywhere? Or if you are feeling bored could you advise the basic core of it yourself?

Thanks
More...

The code is AmiBroker's "AmiBroker Formula Language" (AFL). You can go to the AmiBroker web site (www.amibroker.com) and download the reference manual for the system at no charge. It's a 3 meg PDF file. The entire manual is about 700 pages of which about 300 is the AFL reference.