RE: Welles Wilder's Parabolic SAR

["Yngvi Hardarson" <hardy@xxxxxxxxxxxxx>]

Glen!

Note that this is just an exponential smoothing mechanism and can
be rewritten as

SARt = AF*EPprior + (1-AF)*SARt-1 .

The tricky thing is the formulation of the AF because it may either
speed up or slow down.

I believe I have a description of the mechanism somewhere and will send
it to you once I find it. If I recall correctly you must use external
programming to do it, i.e. DLL. It uses an If Then Else structure.

Yngvi
hardy@xxxxxxxxxxxxx

-----Original Message-----
From: owner-metastock@xxxxxxxxxxxxx
[mailto:owner-metastock@xxxxxxxxxxxxx]On Behalf Of Glen Wallace
Sent: Tuesday, June 26, 2001 15:41
To: MetaStock listserver
Subject: Re: Welles Wilder's Parabolic SAR


Thanks for the LeBeau reference, Lionel.  The formula, from Computer
Analysis of the Futures Market, is:

SARt = SARt-1 + (AF * (EPprior - SARt-1))

Where:
SARt = current SAR (stop and reverse)
SARt-1 = prior SAR
EP = extreme price
AF = acceleration factor.  The AF normally starts at 0.02 and steps up
in increments of 0.02 to a maximum of 0.20.

The difficulty with the MetaStock canned version is that the parabolics
start whenever the prior stop is violated, and not at your entry point.

The code for an entry-point-dependent variation of the parabolic will be
a bit tricky because of the awkwardness in defining the entry price in
MetaStock.  I'll post the code to the list in due course.

Regards.


----- Original Message -----
From: "Lionel Issen" <lissen@xxxxxxxxxxxxxx>
To: <metastock@xxxxxxxxxxxxx>
Sent: Monday, June 25, 2001 5:20 PM
Subject: Re: Welles Wilder's Parabolic SAR

> Glen:
> There are several books that have it. Look at Chuck Lebeau or Perry
Kaufman.
> I think that you might find it easier to use the Metastock version
> Lionel Issen
> lissen@xxxxxxxxxxxxxx
>
>
>
> ----- Original Message -----
> From: "Glen Wallace" <gcwallace@xxxxxxxx>
> To: "MetaStock listserver" <metastock@xxxxxxxxxxxxx>
> Sent: Monday, June 25, 2001 6:04 PM
> Subject: Welles Wilder's Parabolic SAR
>
> > Does anyone have the formula for Welles Wilder's Parabolic
> > SAR or, better yet, the MetaStock code for it?
> >
> > I'm trying to develop an exit that adapts to accelerating price
> > moves and protects profits a bit better than something like
> > Chuck LeBeau's Chandelier exit.
> >
> > Thanks.