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[amibroker] Fair use and fair expectations...



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Hello,

Recently some posts appeard with complaints about RT 'performance'.
There are few things that need to be mentioned:

1. Expecting rock solid stability from BETA  versions of plugins.

Beta software generally speaking is NOT free of bugs and annoyances.
The purpose of the beta software is to check it in "real" environment
on many differently configured computers to find all outstanding
issues that then can be addressed and fixed.

Therefore no one can expect beta version to be rock solid.

2. Exceeding subscription limits

Some people scan/backtest/explore databases of thousands of symbols
having subscribed only to 50 symbols. Although AmiBroker has
mechanisms that dynamically switches active symbols and allows
to have more than your subscription count, one should use
some 'common sense' in using this feature.
For example if using 'wait for backfill' feature and exceeding the limits
of your subscription 10 or 20 times one should not be surprised that
it takes quite a bit of time to backfill hundreds or thousands of symbols,
considering the fact that one symbol 60 day backfill is more than one megabyte
of data. Even on DSL 512kbps it takes 10 or more seconds to download
such history for ONE symbol.

There are physical limitations of  your connection that simply
can not be skipped.

3. Running very complex code on low-end machines.

There were several examples of running very long and complex formulas
over 30000+ data bars each on 300-500MHz processors in tens of windows simultaneously.

In such cases the CPU can simply have not enough time to process
your code. One workaround that can be applied is increasing the
chart refresh interval in Tools->Preferences->Intraday to give the CPU more time
to process your code. Another solution is rewriting your formula.
For example one should use BarIndex() function instead of Cum(1) which
is way slower.

AmiBroker's AFL engine is highly optimized and as you can find out from
running the same backtest/exploration formula on Metastock and AmiBroker,
AFL executes several times faster. I could claim that AFL is actually the fastest
formula language in all T/A programs. But even the fastest engine can be
overloaded. 

Best regards,
Tomasz Janeczko
amibroker.com

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