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User's Guide: Understanding AFL:
http://www.amibroker.com/guide/h_understandafl.html
It is must-read for every newbie.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "sidhartha70" <sidhartha70@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, March 26, 2009 10:17 PM
Subject: [amibroker] Re: I'm having a very hard time doing something that I think should be simple
> If you guys see my post under 'AFL 101' a couple of days back I was saying that the one thing that would have really helped me as
> a newbie was a chapter of the user manual outlining the AmiBroker execution cycle... I think a lack of understanding of that
> execution cycle is what's confusing you guys right now...
>
> Conrad I find your description of what you are seeing very confusing. Can you post the code here and I'm sure you'll get some
> feedback from those of us who have worked a few things out with AB.
>
> --- In amibroker@xxxxxxxxxxxxxxx, Snoopy <snoopy.pa30@xxx> wrote:
>>
>> Conrad,
>>
>> I am a newbie as well, so I might be way off base, and expect more
>> experienced folks to set us straight...
>>
>> I think you (and I) have not fully grasped the ARRAY Processing
>> methodology of AFL.
>>
>> Try thinking of it as if you are using Excel - and you paste a formula
>> into an entire ROW.
>> When you finish the paste, it does the calculation.
>>
>> You (and I) need to better understand what triggers the running of the
>> AFL (I assume a new data bar will trigger it - not sure when - start, or
>> complete).
>>
>> And for your benefit, you could also use the afl functions for First
>> Visible Bar and Last Visible Bar.
>>
>> I hope this helps.
>>
>> Snoopy
>>
>> Conrad Joach wrote:
>> >
>> > I'm just not understanding the way AB is evaluating AFL for a chart.
>> > Let me break it down.
>> >
>> > Let's say I have a database with 100 1 minute bars, 100 minutes of quotes.
>> >
>> > Now let's say I have a chart, and that chart is very narrow and only
>> > shows 10 bars worth of data.
>> >
>> > I write an AFL sript. I want to do a very simple thing.
>> >
>> > For every bar in the series of 100, I want to check if it's visible
>> > (meaning it's inside the 10 bar window that is viewable in the chart),
>> > I want to print the date and time of that bar. For this example let's
>> > say the chart is positioned at the end, showing bar 91-100.
>> >
>> > The script should send the date and time of bars 91-100 to the trace
>> > window. As far as I'm concerned there should only be *10* lines in the
>> > trace window, no more, no less. I guess this means setting the forward
>> > bar padding to 0, and the prior bars to 0.
>> >
>> > But here's the catch. These 100 bars are history. As soon as its
>> > loaded, bar 101 comes in across the wire. The script should only run
>> > *once* for bar 101.
>> >
>> > This is the paradigm I'm used to seeing in almost every other
>> > backtesting system. I don't want my AFL script to run 10 times for
>> > bars 92-101 when that 101st bar crosses the wire. I just want the last
>> > bar evaluated, and the ability to look back at prior bars.
>> >
>> > Where am I going wrong? Many thanks for any help you can provide.
>> >
>> >
>>
>
>
>
>
> ------------------------------------
>
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>
------------------------------------
**** IMPORTANT PLEASE READ ****
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TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at
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