|
PureBytes Links
Trading Reference Links
|
Hello,
Not necesarily last N bars because you can scroll back to say first year visible from those
20 years and then it would represent first N bars.
As for lookback - it is automatically calculated by AmiBroker based on functions you use.
Use Tools->"CHECK" function in the AFL editor to find out how many bars before first visible
and after last visible are required. It was explained on this group a couple of times already.
For example if your formula is
MA( C, 50 ) > C and MA( C, 150 ) > C;
AmiBroker will use 230 bars PRIOR to first visible bar (200 for averages and 30 "extra" padding that
is always added).
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "oneklema" <andy@xxxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Friday, September 07, 2007 4:42 PM
Subject: [amibroker] Re: Simple question about BarCount
> Thanks for your quick help Tomasz. So, BarCount represents the last N
> bars, where N simply varies depending on the zoom factor.
>
> I understand what you are saying with your example of the 20 years of
> data. But also, I can certainly conceive of an indicator (or script)
> that may want a "lookback" to be longer than and independent from the
> zoom factor. Which is why, I'm sure, there is the SetBarsRequired()
> function.
>
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>>
>> BarCount does not represent number of bars in the DATABASE,
>> but in the ARRAYs in current execution.
>>
>> The arrays have DYNAMIC size depending on zoom factor. That's why
> BarCount may and will vary.
>>
>> For example if you have 20 years of data and you are watching just
>> the last year
>> AmiBroker does not need and does not use all bars in the database to
> calculate
>> indicators for last year.
>>
>> It uses last year only PLUS some previous bars required to
> "stabilise" indicator values.
>> The number of extra bars depends on functions you use in the formula.
>>
>> If you want to use truly all bars you need to use SetBarsRequired
> function:
>> http://www.amibroker.com/f?setbarsrequired
>>
>> Best regards,
>> Tomasz Janeczko
>> amibroker.com
>> ----- Original Message -----
>> From: "oneklema" <andy@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Friday, September 07, 2007 3:45 PM
>> Subject: [amibroker] Simple question about BarCount
>>
>>
>> >I have what should be a simple question about BarCount but cannot get
>> > a definitive answer from the AB documentation. FYI, I am working on
>> > daily data.
>> >
>> > What exactly does BarCount represent? The AB help says:
>> >
>> > BarCount constant gives the number of bars in array (such as Close,
>> > High, Low, Open, Volume, etc). Array elements are numbered from 0
>> > (zero) to BarCount-1.
>> >
>> > So, I understand that it is the size of the arrays (I'm an old C
>> > programmer). But, I assumed that if I have a loop such as:
>> > for (i = 0; i < BarCount, i++)
>> > {
>> > do work on C[i];
>> > }
>> >
>> > I would do work on every Close value that is *in the database for the
>> > symbol that is opened*. But, it does not seem to work this way (?).
>> >
>> > When I print out the value of BarCount, I notice that it changes as I
>> > change the Zoom factor (i.e., clicking +,-). And, the only way to get
>> > BarCount to reflect all data is to zoom as as far as it can go. So, I
>> > thought maybe it represents the number of bars displayed as adjusted
>> > by the zoom. But, from a visual inspection, it is obviously not that
>> > (maybe related, but not exact).
>> >
>> > Is there any way to operate on symbol data for all data that has been
>> > loaded into the database, regardless of the zoom factor?
>> >
>> >
>> >
>> > 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
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/amibroker/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/amibroker/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:amibroker-digest@xxxxxxxxxxxxxxx
mailto:amibroker-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
amibroker-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|