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.
