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Ara,
TJ said on Aug 6, 2007: "More likely than not, one of upcoming
versions will have "static arrays"."
I will make a formal suggestion or bug report as soon as I am
convinced that I am not at fault here. I prefer to make sure I
understand the problems are real before cluttering up the bug reports
or suggestions with my errors in understanding --I have already made
that mistake a couple of times.
Best regards,
Dennis
On Sep 13, 2007, at 2:12 PM, Ara Kaloustian wrote:
> Dennis,
>
> I did not dig into your code, but you seem to have spent a lot of
> time and
> systematically isolated the issues / problems.
>
> TJ has stated that ATCs are best way to have static arrays and they
> are
> fairly fast because they are cashed.
>
> TJ's plan (at least as far as I can understand) does not include
> any static
> arrays in foreseeable future, as they are not any faster than ATCs.
>
> Clearly we do need static array functions and TJ's solution is, (at
> lease
> for now) ATCs.
>
> Seems like it would be appropriate to report this as a "bug" or make a
> suggestion for improving the system behavior.
>
> The need for "static arrays" is obvious and will probably only
> increase.
>
> Ara
> ----- Original Message -----
> From: "Dennis Brown" <see3d@xxxxxxxxxxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Thursday, September 13, 2007 10:14 AM
> Subject: [amibroker] SetBarsRequired() messing up AddToComposite()
>
>
>> Hello,
>>
>> I have made a number of posts in the past asking for help
>> understanding how some AFL things work that were causing me
>> problems. Today, I see that some of these issues are related to each
>> other.
>>
>> Most seem to be related to the number of bars that are loaded for an
>> operation.
>>
>> 1. SetBarsRequired()
>>
>> I reduce the number of bars for calculating some of my slow loops to
>> increase speed.
>> At TJ's suggestion, I also placed a SetBarsRequired(barHistory, 0);
>> at the end of my AFL which overrides the Fast AFL settings.
>> barHistory is set by parameter to the number of bars I want to see in
>> my charts.
>>
>> This was a great help in AFL execution speed. However, the
>> SetBarsRequired() statement is peak detecting as long as the chart is
>> running. That means that if I want to see 50,000 bars instead of
>> 2,000 bars for a moment, the number of bars loaded will go up to
>> 50,000 when I increase them, but will never be reduced when I set the
>> number back to 2,000. So the slow down is permanent after that until
>> I restart AB (or edit my chart AFL). Not ideal from my perspective.
>>
>> 2. AddToComposite()
>>
>> The first use of an AddToComposite() has the effect of requiring
>> 1,000,000 bars back and 1,000,000 forward in fast AFL. Once
>> executed, you can never go back to fast AFL.
>>
>> This can have a bad side effect for some ATC uses. In my case, I
>> wanted to use an ATC ticker to hold flags to indicate a manual
>> trade. Normally my code only needs 2000 bars loaded. When I load in
>> the ticker with foreign() and modify a bar, then use ATC to write it
>> back out, it does not write it out correctly The FIRST time. This is
>> because the number of bars required was less at the time the Foreign
>> () function was executed and the number required for the ATC was all
>> bars, which does not take effect until the next pass of AFL for the
>> next Foreign() function execution. This is messy to understand, and
>> I do not fully comprehend all the details of it, except the first ATC
>> write was not correct.
>>
>> However, the SetBarsRequired() command at the end of the AFL
>> overrides this behavior, and keeps the number of bars the same as
>> before. This leads to a similar problem, only now every ATC write is
>> bad unless the SetBarsRequired() command includes all bars, which
>> defeats the purpose of speeding up the AFL.
>>
>> 3. My questions
>>
>> Have I described what is happening correctly?
>>
>> How do I get the number of bars loaded to match the SetBarsRequired()
>> command when I want to reduce the number?
>>
>> In order to have fast execution, am I going to have to abandon my use
>> of ATC for saving static arrays?
>>
>> What other approach could I use to have high speed AFL and also be
>> able to transfer array data between charts without using ATC?
>>
>>
>> 4. The AFL which demonstrates the First ATC write problem :
>>
>> _SECTION_BEGIN("Manual Trades");
>> // This section allows manual trades to be entered and saved
>> permanently as a ticker
>> // ~name1 is Buy flags
>> // ~name2 is Sell flags
>> // ~name3 is Short flags
>> // ~name4 is Cover flags
>>
>> function saveManual(array, ManName)
>> {AddToComposite(array ,ManName ,"x",atcFlagEnableInIndicator|
>> atcFlagDefaults);}
>>
>> function saveAllManual(BuyMan, SellMan, ShortMan, CoverMan, ManName)
>> {
>> saveManual(BuyMan , ManName+"1");
>> saveManual(SellMan , ManName+"2");
>> saveManual(ShortMan , ManName+"3");
>> saveManual(CoverMan , ManName+"4");
>> }
>>
>> ManualName = ParamStr("Manual Trade Ticker", "~Kezha");
>> createManual = ParamTrigger("Make Empty Ticker", "Make Empty
>> Ticker" );
>> EnableManual = ParamToggle("Enable Manual Trades", "OFF|ON" );
>> setbuy = ParamTrigger("Buy", "Buy" );
>> setsell = ParamTrigger("Sell", "Sell" );
>> setshort = ParamTrigger("Short", "Short" );
>> setcover = ParamTrigger("Cover", "Cover" );
>> clear = ParamTrigger("Clear", "Clear" );
>>
>> bi = BarIndex();
>> sbi = SelectedValue( bi )-bi[0];
>>
>> if( createManual )
>> {
>> saveAllManual(0, 0, 0, 0, ManualName);
>> }
>>
>> if( enableManual )
>> {
>> BuyMan = Foreign(ManualName+"1" ,"H");
>> SellMan = Foreign(ManualName+"2" ,"H");
>> ShortMan = Foreign(ManualName+"3" ,"H");
>> CoverMan = Foreign(ManualName+"4" ,"H");
>>
>> if( setbuy ){BuyMan[sbi ] = 1; saveManual(BuyMan , ManualName+"1");}
>> if( setsell ){SellMan[sbi ] = 1; saveManual(SellMan, ManualName
>> +"2");}
>> if( setshort ){ShortMan[sbi ] = 1; saveManual(ShortMan, ManualName
>> +"3");}
>> if( setcover ){CoverMan[sbi ] = 1; saveManual(CoverMan, ManualName
>> +"4");}
>> if( clear )
>> {
>> BuyMan[sbi ] = 0;
>> SellMan[sbi ] = 0;
>> ShortMan[sbi ] = 0;
>> CoverMan[sbi ] = 0;
>> saveAllManual(BuyMan, SellMan, ShortMan, CoverMan, ManualName);
>> }
>> PlotShapes( BuyMan * shapeUpArrow,colorGreen,0,L,-25);
>> PlotShapes( SellMan * shapeDownArrow ,colorRed ,0,H,-25);
>> PlotShapes( ShortMan * shapeHollowDownTriangle ,colorRed ,0,H,-25);
>> PlotShapes( CoverMan * shapeHollowUpTriangle,colorGreen,0,L,-25);
>> }
>> _SECTION_END();
>>
>> Thank you,
>> Dennis Brown
>>
>>
>> Please note that this group is for discussion between users only.
>>
>> To get support from AmiBroker please send an e-mail directly to
>> SUPPORT {at} amibroker.com
>>
>> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> http://www.amibroker.com/devlog/
>>
>> For other support material please check also:
>> http://www.amibroker.com/support.html
>>
>> Yahoo! Groups Links
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>
>
>
> Please note that this group is for discussion between users only.
>
> To get support from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
>
> Yahoo! Groups Links
>
>
>
Please note that this group is for discussion between users only.
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SUPPORT {at} amibroker.com
For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
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