[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[amibroker] Re: How to code a Adaptive StDev()



PureBytes Links

Trading Reference Links

Brian -

Tomasz put it well.  If curiosity gets to you here's a reference.  Look for the section titled Simplification of the Formula -

http://en.wikipedia.org/wiki/Standard_deviation

-- BruceR 



--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>
> This formulation is in every algebra book and used in school often
> because it is quicker even for human to calculate that way.
> 
> Best regards,
> Tomasz Janeczko
> amibroker.com
> ----- Original Message ----- 
> From: "brian_z111" <brian_z111@xxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Monday, June 15, 2009 12:06 AM
> Subject: [amibroker] Re: How to code a Adaptive StDev()
> 
> 
> > Nice work Bruce.
> > 
> > I was trying to make up my own algebraic equivalent in lieu of a reference source, or sources.
> > 
> > 
> > Did you get 'your' version of StDev from a reference of is it your own work?
> > 
> > --- In amibroker@xxxxxxxxxxxxxxx, "bruce1r" <brucer@> wrote:
> >>
> >> Herman, Mike, all - just checking in and think I can offer a quick
> >> suggestion and some code that I have handy.
> >> 
> >> 1.  StDev() is a function that is not implemented as a variable period
> >> function, but can be with a slight caveat.  Because this uses an
> >> alternative, but algebraically equivalent formulation, that employs a
> >> "data^2" term, it loses precision at about the 5th significant digit. 
> >> That is close enough for most work, though.  So, anyway, this one liner
> >> function will give a fast, variable period StDev ( IOW, vper can be a
> >> varying array) -
> >> 
> >> function StDevVarPer( data, Vper )
> >> {
> >> return  sqrt( MA( data ^ 2, vper ) - MA( data, vper ) ^ 2 );
> >> }
> >> 
> >> 2.  This is fast even with large numbers of 1 minute bars, but it is
> >> usually best to control QuickAFL with a statement like the following as
> >> the LAST STATEMENT in the program to yield maximum performance -
> >> 
> >> SetBarsRequired( 500, 0 );
> >> 
> >> Remember that with QuickAFL in an indicator, the first execution after
> >> an edit or insert passes the entire array to set the bar requirement,
> >> then QuickAFL is in force on a subset.
> >> 
> >> -- BruceR
> >>
> > 
> > 
> > 
> > 
> > ------------------------------------
> > 
> > **** IMPORTANT PLEASE READ ****
> > This group is for the discussion between users only.
> > This is *NOT* technical support channel.
> > 
> > TO GET TECHNICAL SUPPORT send an e-mail directly to 
> > SUPPORT {at} amibroker.com
> > 
> > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
> > http://www.amibroker.com/feedback/
> > (submissions sent via other channels won't be considered)
> > 
> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> > http://www.amibroker.com/devlog/
> > 
> > Yahoo! Groups Links
> > 
> > 
> >
>




------------------------------------

**** IMPORTANT PLEASE READ ****
This group is for the discussion between users only.
This is *NOT* technical support channel.

TO GET TECHNICAL SUPPORT send an e-mail directly to 
SUPPORT {at} amibroker.com

TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
http://www.amibroker.com/feedback/
(submissions sent via other channels won't be considered)

For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
http://www.amibroker.com/devlog/

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/amibroker/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/amibroker/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:amibroker-digest@xxxxxxxxxxxxxxx 
    mailto:amibroker-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    amibroker-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/