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Hello,
Using SetBarsRequired() is recommended because it is local to single
formula. Turning QuickAFL globally off (in prefs) is highly discouraged.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "jtelang" <jtelang@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Sunday, September 14, 2003 8:44 PM
Subject: [amibroker] BarCount problem... (Was: Re: Strange behavior...)
> Thanks, that was it.
>
> Yes, I knew BI and BC are different. I was just demonstrating that BI
> crossed BC, which I wasn't expecting. One more question.. I see the
> right behavior by either turning QuickAFL off or by setting bars
> required to a high value. Is one better than the other, given that I
> must loop over BarCount to feed values in the array?
>
> TIA,
>
> Jitu
>
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <amibroker@xxxx>
> wrote:
> > Hello,
> >
> > No these two are not the same.
> > BarIndex() is an index of current QUOTE bar
> > - ARRAY. It is equivalent to Cum(1)-1. This counts
> > bars from the very first bar to the very last bar.
> >
> > BarCount is a CURRENT SIZE of array (single NUMBER)
> >
> > In Indicator Builder the arrays used for calculations
> > may be SMALLER than number of quotes when QuickAFL feature is
> enabled.
> >
> > Enable QuickAFL(tm) for indicators - this turns on QuickAFL(tm)
> feature that causes faster charts redraws. QuickAFL works so it
> > calculates only part of the array that is currently visible. If you
> use this feature and your formulas are script based you should
> > add SetBarsRequired function to your code. Recommended especially
> when you work with data that have more than 10000 bars. Note: for
> > certain indicators requiring recursive calculation, enabling this
> feature may lead to small (less than 0.05%) differences in values
> > of indicators (not visible for the eye), due to the fact that not
> all bars available are included in the calculation.
> >
> > See also comment to BarCount in "what's new section":
> > - added built-in constant 'BarCount' that returns number of bars
> available in arrays (the number of elements of array)
> > When QuickAFL is turned on it may be less than true number of bars
> because QuickAFL feature attempts to use only visible bars (and
> > few before). You can control how many bars the formula requires
> using SetBarsRequired() function
> >
> >
> > And see this too: http://www.amibroker.com/guide/afl/afl_view.php?
> name=SETBARSREQUIRED
> >
> >
> > Best regards,
> > Tomasz Janeczko
> > amibroker.com
> > ----- Original Message -----
> > From: "jtelang" <jtelang@xxxx>
> > To: <amibroker@xxxxxxxxxxxxxxx>
> > Sent: Sunday, September 14, 2003 8:09 PM
> > Subject: [amibroker] BarCount problem... (Was: Re: Strange
> behavior...)
> >
> >
> > > TJ,
> > >
> > > The problem I'm experiencing seems to be related to BarCount's
> value.
> > > I'm seeing following behavior with multiple databases.
> > >
> > > If I plot BarIndex() and BarCount values (with default DB that
> came
> > > with the install) as -
> > >
> > > Plot(BarIndex(), "BI", colorBlue);
> > > Plot(BarCount, "BC", colorRed);
> > >
> > > - what I see is that BC starts with 159 at the start of the chart,
> > > increases by 1, until it reaches 189 and stays there. In the
> > > meanwhile, BI starts with zero, crosses BC at 189, and goes all
> the
> > > way to 356.
> > >
> > > Isn't BC always supposed to be 357? Do you have any idea what
> could
> > > be causing this? Like I said, I see similar behavior with any DB
> that
> > > I use. I'm using 4.41 Beta (built on 9/2).
> > >
> > > Another interesting thing to note is that when I insert this
> > > indicator, BC does show 357 as the value, but as soon as I click
> > > anywhere in the chart, it shows the values as described above.
> > >
> > > TIA.
> > >
> > > Jitu
> > >
> > > --- In amibroker@xxxxxxxxxxxxxxx, "jtelang" <jtelang@xxxx> wrote:
> > > > Typo in the pseudo-code. It should read -
> > > >
> > > > -------
> > > >
> > > > handle = LoadTableAndGetHandle();
> > > > col = GetWhichColToDisplay();
> > > > val = 0; // Value to display
> > > >
> > > > for( i = 0; i < BarCount; i++ ) {
> > > > val[i] = GetValFromTable(handle, i, col); // i being the row
> > > > }
> > > >
> > > > ------
> > > > --- In amibroker@xxxxxxxxxxxxxxx, "jtelang" <jtelang@xxxx>
> wrote:
> > > > > TJ,
> > > > >
> > > > > I'm using a ABTool-managed, externally stored table to store
> some
> > > > > calculated data for each symbol. When I try to display a
> value in
> > > > the
> > > > > column from an indicator, I see a rather strange behavior.
> Say my
> > > > > indicator is something like following pseudo-code -
> > > > >
> > > > > ----------
> > > > >
> > > > > handle = LoadTableAndGetHandle();
> > > > > col = GetWhichColToDisplay();
> > > > > val = 0; // Value to display
> > > > >
> > > > > for( i = 0; i < BarCount; i++ ) {
> > > > > val = GetValFromTable(handle, i, col); // i being the row
> > > > > }
> > > > >
> > > > > -----------
> > > > >
> > > > > When I first time insert this indicator, a plot gets created
> with
> > > > > values shown. However as soon as I click somewhere else in the
> > > > chart,
> > > > > all values displayed drop to zero (may be because I
> initialized
> > > it
> > > > to
> > > > > zero?). Then onwards, if I click "Edit Formula" again and hit
> > > > Apply,
> > > > > the values flash on the chart for a fraction of a second, and
> > > then
> > > > > disappear.
> > > > >
> > > > > I'm not sure if this is ABTool problem (I've posted a
> question on
> > > > > their list to figure out what the best way to display the
> values
> > > > is),
> > > > > but what could cause the chart to behave this way? I've tried
> a
> > > > > number of things, such as defining handle as "handle[0]" to
> see
> > > if
> > > > it
> > > > > loads the file only once, or just loading it inside the loop
> only
> > > > > when "i == 0" and then reusing the handle value, etc, but to
> no
> > > > avail.
> > > > >
> > > > > Any ideas?
> > > > >
> > > > > TIA,
> > > > >
> > > > > Jitu
> > >
> > >
> > >
> > > Send BUG REPORTS to bugs@xxxx
> > > Send SUGGESTIONS to suggest@xxxx
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> > >
> > >
> > >
>
>
>
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>
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