Re: [amibroker] How To Restore Formula Speed?

["Tomasz Janeczko" <groups@xxxxxxxxxxxxx>]

Percentile involves sorting, it is currently implemented

using absolutely the fastest algorithm known to human kind.

 

What you can do to speed it up - that's easy - call it once

and store result.

This (calling same functions with same arguments many times instead calling it once) 

is the most common mistake people are making.

 

Best regards,
Tomasz Janeczko
amibroker.com

----- Original Message -----

From: Louis Préfontaine

To: amibroker@xxxxxxxxxxxxxxx

Sent: Sunday, May 11, 2008 4:15 PM

Subject: Re: [amibroker] How To Restore Formula Speed?

Hi Tomasz,

Is there a way to speed up Percentile function?

Thanks,

Louis

2008/5/11 Tomasz Janeczko <groups@xxxxxxxxxxxxx>:

Hello,

Use
AFL Editor,
Tools->Check and Profile
to find the bottleneck in your code.

Most often people are
calling the same funciton over and over many times when
they should call it ONCE and store the result in variable.
This the most basic improvement can be applied to 99% of
formulas written and posted here to get a lot more speed.
The other thing is that you move all array function calls OUTSIDE
loops. That's second principle: *never* call array function
inside loop , unless you are doing something like iterating
through multiple symbols. But NEVER call array funcitons
inside per-bar loop.

Best regards,
Tomasz Janeczko
amibroker.com

----- Original Message -----
From: "ondrej.uhlarik" <ona@xxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Sunday, May 11, 2008 2:44 PM
Subject: [amibroker] How To Restore Formula Speed?

> Hello,
> I have programed quite a complicated indicator in AFL. When I load it
> in a pane it significantly slows down scrolling speed and reaction
> speed in general. That I find very annoying, so I made a Toggle
> parameter to switch between 2 modes: Basic (which does not show so much
> but does not affect speed so much either) and Advanced (which shows
> everything and affects speed a lot). Now the problem is as follows:
> I insert the indicator in a pane in the Basic mode and the speed is ok.
> Then I switch to the Advanced mode and the speed gets worse. Then I
> switch back to the Basic mode but the speed remains bad, i.e. the
> original speed is not restored. It seems that the Advanced data are
> still loaded in some memory cache and affect speed of the indicator
> even if I switch back to the Basic mode. Is there any chance to clear
> or reset the data loaded in memory (or whatever) without removing the
> indicator from the pane and re-inserting it back?
> Thank you for your ideas, and please keep in mind that I am a beginner
> in programing :)
>
>

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