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" <[EMAIL PROTECTED]> To: <[email protected]> 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 > > > > > > > > > > > > > > > > > > > > ----- Original Message ----- > From: "sidhartha70" <[EMAIL PROTECTED]> > To: <[email protected]> > 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 [email protected], "Tomasz Janeczko" <[EMAIL PROTECTED]> >> 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" <[EMAIL PROTECTED]> >>> To: <[email protected]> >>> Sent: Thursday, August 21, 2008 2:48 PM >>> Subject: [amibroker] Re: Size of Database... >>> >>> >>> > Anyone...? >>> > >>> > Many Thanks >>> > >>> > --- In [email protected], "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 > > > >
