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Static arrays - I'll tell you a way to do it without ATC that I've
used, but it comes with cautions. I did it prior to the change to
allow ATC's in indicators. Performance wise, it is faster, but
not that much since I suspect TJ optimized ATC and Foreign.
BUT, please observe the following constraint -
FOR THIS TECHNIQUE TO WORK , IN THE AA SETTINGS YOU MUST PAD AND ALIGN
ALL DATA TO A REFERENCE SYMBOL
BTW, you might generally think that this is a bad thing to do, but it
is actually useful. If you know that you are only interested in
recent history in a scan or explore, you can greatly speed up lengthy
ones by using a reference symbol with limited history - like UCPIX -
whose history starts on in 2004.
(I really wish that TJ would expose this thru automation ! )
So, say that you use pad and align, you can use the Windows Scripting
Dictionary to hold the arrays. This comes in all recent versions of
IE/VBScript, and has many uses. It is really easy to use, but you must
do the following to make sure it stays in memory -
dict = CreateStaticObject( "scripting.dictionary" );
Variant entries are referenced by key - so say that you have an array
that you want to store with a key or name, the following form will add
or update an entry (why the update has to be done this way isn't
important here) -
if ( dict.exists( key ) )
dict.remove( key );
dict.add( key, array );
To retrieve an entry -
array = dict.item( key );
Lastly, there is a RemoveAll() method that can be handy.
REMEMBER - you must use "Pad and align all data to reference symbol".
Again, though, before TJ shoots me <g>, I'd advise against this for
most everyone because if you are not careful, things can get ugly.
I'd suggest just using ATC.
Bruce R.
--- In amibroker@xxxxxxxxxxxxxxx, "Ara Kaloustian" <ara1@xxx> wrote:
>
> Thanks Bruce
>
> ----- Original Message -----
> From: "bruce1r" <brucer@xxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Sunday, June 24, 2007 5:39 AM
> Subject: [amibroker] Re: VBScript / Jscript
>
>
> > Ara -
> >
> > I addressed it - just not in detail. I mentioned that ATC's normally
> > operate out of ticker data cache. AB maintains its own memory cache
> > for ticker data. So, your retrievals of your ATC "static" arrays
> > should be coming from this memory via a Foreign() call - and this is
> > fast. They are probably not coming from disk. So, I can think of
> > only three remotely possible reasons that you might see disk reads -
> >
> > 1. The settings in Tools/Preferences/Data are unusually small for the
> > cache, and the ATC tickers cannot be kept there. This seems
unlikely.
> >
> > 2. AB has a bug that flushes the cache. Unlikely knowing TJ, and it
> > probably would have been noticed by now.
> >
> > 3. Your watchlist is lengthy or you do a large number of foreign's
> > that flush the ATC's out of the cache. Also unlikely.
> >
> > BUT, I said that I would show you a hack for static arrays, and I'll
> > do it in the a follow-up post to this.
> >
> > Bruce R.
> >
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