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Hello,
They are indeed recalculated when going through several backtests.
You could store such values in static variables and use them later in subsequent runs,
but it is in most cases _wasted_ effort, because array functions like MA( C, 15 ) are EQUALLY fast
as STATIC variables. This is so because static variables requires one pass any way (date/time synchronization)
the same as MA. MA can actually be slightly faster than static array variable because of locality of reference.
Situation is different with normal variables (as I pointed out in my previous post), because normal variables
do not require synchronization (they are already in perfect sync) and do not require extra memory
nor ANY computation as they are simple POINTERS to values that were returned by function.
Storing/reading a pointer to array is a matter of single CPU instruction, i.e. is blazing fast (one CPU clock cycle).
Regarding AddToComposite/Foreign - they are way slower than Static variables, so it makes no sense to use them for that purpose.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "Bisto" <bistoman73@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Tuesday, October 06, 2009 1:52 PM
Subject: [amibroker] Re: Tips for reducing CPU load
>I was thinking about this issue yesterday and I have a question, please correct me if I am wrong:
>
> During an optimization process there are so many repetitions of a function with invariant parameter equal to the total number of
> the steps of the optimization.
>
> In this case MA(C,15) will be calculated for every set of optimization parameter even if it is invariant, OK?
>
> If we have a very time consuming invariant function in the TS it will be calculated a lot of times even if it is not needed. This
> is true if I have well interstood how AB works, please correct me
>
> my idea is to store this very time consuming invariant function in a "fake" symbol (using Addtocomposite) and access to its values
> by Setforeing.
>
> Is it a good idea?
>
> Bisto
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>>
>> Hello,
>>
>> For example, take a look at this simple code:
>>
>> Buy = Cross( MA(C, 5 ), MA( C, 15 ) );
>> Sell = Cross( MA( C, 15 ), MA( C, 5 ) );
>>
>> There are 2 repetitions of same function call with invariant parameters:
>> MA(C, 5 ) - is called twice
>> MA( C, 15 ) - is called twice
>>
>> This can be written in more efficient manner using variables:
>>
>> shortma = MA(C, 5 );
>> longma = MA( C, 15 );
>> Buy = Cross( shortma, longma );
>> Sell = Cross( longma, shortma );
>>
>> That is what I meant.
>>
>> Best regards,
>> Tomasz Janeczko
>> amibroker.com
>> ----- Original Message -----
>> From: "Rob" <sidhartha70@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Tuesday, October 06, 2009 10:21 AM
>> Subject: [amibroker] Re: Tips for reducing CPU load
>>
>>
>> > TJ,
>> >
>> > Sorry my programming terminology is not as good as yours...
>> > What do you mean by 'replacing repeated function calls with invariant parameters'...??
>> >
>> > --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@> wrote:
>> >>
>> >> First and foremost: use AFL Editor, Tools->Code Check And Profile
>> >> to reduce complexity of your code, by removing repeated function calls (with invariant parameters),
>> >> using array operators wherever possible instead of loops,
>> >> re-thinking code to get simpler formulation,
>> >> avoiding any JScript/VBScript / COM objects in charts, etc.
>> >>
>> >> Best regards,
>> >> Tomasz Janeczko
>> >> amibroker.com
>> >> ----- Original Message -----
>> >> From: "Ara Kaloustian" <ara1@>
>> >> To: <amibroker@xxxxxxxxxxxxxxx>
>> >> Sent: Tuesday, October 06, 2009 12:23 AM
>> >> Subject: Re: [amibroker] Tips for reducing CPU load
>> >>
>> >>
>> >> >- review your memory settings in preferences... make sure you are not
>> >> > allocating memory that you are not using
>> >> >
>> >> > - reduce number of symbols you monitor if you don't need them all
>> >> >
>> >> >
>> >> > ----- Original Message -----
>> >> > From: "Rob" <sidhartha70@>
>> >> > To: <amibroker@xxxxxxxxxxxxxxx>
>> >> > Sent: Monday, October 05, 2009 2:33 PM
>> >> > Subject: [amibroker] Tips for reducing CPU load
>> >> >
>> >> >
>> >> >> Hi All,
>> >> >>
>> >> >> I seem to be maxing out the core I'm using on AB... starting to cause
>> >> >> problems operationally. I'm mainly doing charting and real time AFL.
>> >> >>
>> >> >> Any tips for reducing CPU load so I can perhaps give myself a little more
>> >> >> breathing space....??
>> >> >>
>> >> >> TIA
>> >> >>
>> >> >>
>> >> >>
>> >> >> ------------------------------------
>> >> >>
>> >> >> **** IMPORTANT PLEASE READ ****
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>> >> >> TO GET TECHNICAL SUPPORT send an e-mail directly to
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>> >> >>
>> >> >>
>> >> >>
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > ------------------------------------
>> >> >
>> >> > **** 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
>> >> >
>> >> >
>> >> >
>> >>
>> >
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > **** 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
>> >
>> >
>> >
>>
>
>
>
>
> ------------------------------------
>
> **** 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
>
>
>
------------------------------------
**** 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/
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