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Hi Ron - I believe the user does have final control over how far AB looks
back. If you place SetBarsRequired at the *end* of your code I think it will
override what AB has previously calculated. It is discussed in the recent
ReadMe file.
Steve
----- Original Message -----
From: "Ronald Davis" <xokie7@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, August 21, 2008 4:24 PM
Subject: Re: [amibroker] Re: Size of Database...
> sidhartha70>>>So as a DB management strategy, it's best to perhaps have a
> large DB
> for backtesting purposes only... and a much smaller DB for live
> trading, charting, symbol swithcing etc..etc...??
> ------------------------------------------------------------------------------------------
> I think I remember that SET BARS REQUIRED will "NOT" stop Amibroker from
> looking back through the last 30 years even though I am looking at only
> the
> last day.
>
> I would sure like a feature in Amibroker that would make SET BARS REQUIRED
> lookback only 101 days when the indicator looks back only 100 days.
>
> My backtesting days officially ended a few days ago.
>
> My backtesting consisted of viewing my indicator buy signals against 30
> years of historical data.
>
> Even though I no longer backtest, I would still like to have a 30 year
> database, and here is why.
>
> Those symbols that are less volatile tend to have a decent amount of
> pattern
> similarity in my indicators as they enter into a NEW uptrend, after
> having
> been on a long term DOWNTREND.
>
> If I keep my 30 year database, then when I get a BUY signal, I can look
> back
> at the beginning of the previous new uptrends that occurred over the last
> 30
> years. This lookback helps me decide how good the signal is. Ron D
>
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> ----- Original Message -----
> From: "sidhartha70" <sidhartha70@xxxxxxxxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Thursday, August 21, 2008 8:59 AM
> Subject: [amibroker] Re: Size of Database...
>
>
>> Thanks TJ.
>>
>> So as a DB management strategy, it's best to perhaps have a large DB
>> for backtesting purposes only... and a much smaller DB for live
>> trading, charting, symbol swithcing etc..etc...??
>>
>> Thanks
>>
>> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>>>
>>> Using 10x more data per symbol will give you slow down in all areas.
>>> 2 million bars is 64 MB per symbol of quote data and 8 MB per single
>> AFL array
>>> (if quickafl is not used). As formulas depending on complexity can
>> use hundreds of arrays
>>> this means approaching gigabytes of RAM.
>>> Handling that much of data is not "easy". Remember than RAM bandwidth
>>> is limited to few GB per second. Therefore just accessing that amount
>>> of data is question of seconds, not counting the calculations.
>>>
>>> Best regards,
>>> Tomasz Janeczko
>>> amibroker.com
>>> ----- Original Message -----
>>> From: "sidhartha70" <sidhartha70@xxx>
>>> To: <amibroker@xxxxxxxxxxxxxxx>
>>> Sent: Thursday, August 21, 2008 2:48 PM
>>> Subject: [amibroker] Re: Size of Database...
>>>
>>>
>>> > Anyone...?
>>> >
>>> > Many Thanks
>>> >
>>> > --- In amibroker@xxxxxxxxxxxxxxx, "sidhartha70" <sidhartha70@> wrote:
>>> >>
>>> >> This may have been answered before, but...
>>> >>
>>> >> I set up two DB's in AB... both IQ Feed tick DB's.
>>> >>
>>> >> 1. Is 200,000 bars per symbol.
>>> >> 2. The second is 2,000,000 per symbol.
>>> >>
>>> >> Practially, operationally, where will AB be slower in the use of the
>>> >> second DB...?? In charting? Backtesting (obviosuly)? In symbol
>>> >> switching etc...?
>>> >>
>>> >> I'm just trying to work out how motivated I should be to have small
>>> >> DB's...
>>> >>
>>> >> Thanks
>>> >>
>>> >
>>> >
>>> >
>>> > ------------------------------------
>>> >
>>> > 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.
>>
>> 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.
>
> 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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