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" <[email protected]> To: <[email protected]> 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 [email protected], Snoopy <snoopy.p...@...> 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. >> > >> > >> > > > > > ------------------------------------ > > **** 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 > > >
