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Herman,
It is because your formula calls LinearReg inside
loop so many times that requirements are added up so
it effectively turns off QuickAFL at
all.
Use instead this code:
array = 0<FONT
face="Courier New">; T1 = <FONT
color=#0000ff>LinearReg(<FONT
color=#0000ff>LinearReg(<FONT
color=#000000>C,<FONT
color=#ff00ff>20),<FONT
color=#ff00ff>20);
for<FONT
color=#000000>(bar=0;
bar<BarCount<FONT
face="Courier New">; bar++) { LRR[bar] = T1[bar];
array[ bar ] = bar; } bi=<FONT
color=#0000ff>BarIndex<FONT
color=#000000>(); Plot<FONT
color=#000000>( array, "bar"<FONT
color=#000000>, colorRed<FONT
face="Courier New"> ); <FONT
color=#0000ff>Plot( <FONT
color=#0000ff>BarIndex(), <FONT
color=#ff00ff>"QuickAFL start bar = "+bi[<FONT
color=#ff00ff>0]+" End bar
= "+bi[<FONT
color=#000000>BarCount-<FONT
color=#ff00ff>1] + "
NumBars =" + <FONT
color=#000000>BarCount, <FONT
color=#000000>colorBlue );
Loop-invariant part moved outside the loop (basic
programming principle)
Best regards,Tomasz Janeczkoamibroker.com
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
Herman van den
Bergen
To: <A title=amibroker@xxxxxxxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Sunday, July 25, 2004 5:48 PM
Subject: RE: [amibroker] Looping within
QuickAFL bounds
TJ,
i did NOT use Apply. I emailed test result emailed to you privately for your
persusal.
<FONT face=Arial color=#0000ff
size=2>
best
regards,
<FONT face=Arial color=#0000ff
size=2>herman.
<FONT face=Tahoma
size=2>-----Original Message-----From: Tomasz Janeczko
[mailto:amibroker@xxxxxx]Sent: Sunday, July 25, 2004 10:11
AMTo: <A
href="">amibroker@xxxxxxxxxxxxxxxSubject:
Re: [amibroker] Looping within QuickAFL boundsImportance:
High
Herman,
The last sentence from my previous
e-mail should give you an answer:
"Please note that the very <FONT
color=#800000>first exectution after clicking "APPLY" in Indicator
Builder uses always *ALL* bars
because
it needs to analyse your code and its
requirements. Only subsequent executions use QuickAFL (less
bars)."
Best regards,Tomasz
Janeczkoamibroker.com
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
Herman van den
Bergen
To: <A
title=amibroker@xxxxxxxxxxxxxxx
href="">amibroker@xxxxxxxxxxxxxxx
Sent: Sunday, July 25, 2004 1:38
PM
Subject: RE: [amibroker] Looping
within QuickAFL bounds
<FONT face=Arial color=#0000ff
size=2>Tomasz, I understand what you are saying.... But if I test the
code below using DebugView and i get 0.43 Second
execution regardless of wether I have QuickAFL set
On or OFF. So it appears that in this case QuickAFL does not
restrict my loops to its bounds...( i used AB 4.6, EOD data, max zoom
(10bars displayed)). Now if I set the loop to start at Barcount-40 to
cover only the data I think i should i get a dramatic improvement in
execution - which is what i want. <SPAN
class=406480511-25072004><FONT face=Arial color=#0000ff
size=2>What am i doing
wrong?
<SPAN
class=406480511-25072004><FONT face=Arial color=#0000ff
size=2>h<SPAN
class=406480511-25072004>erman<SPAN
class=406480511-25072004><FONT
color=#0000ff>_TRACE(<FONT
color=#ff00ff>"#Start");array =
0<FONT
size=2>;<FONT
face="Lucida Console" color=#800000>for<FONT
size=2>(bar=<FONT
face="Lucida Console" color=#ff00ff>0<FONT
face="Lucida Console">; bar<BarCount; bar++) {
T1=LinearReg(<FONT
color=#0000ff>LinearReg(C,<FONT
color=#ff00ff>20),20); <FONT
size=2>// just to slow things down a
bitLRR[bar] = T1[bar];<FONT
face="Lucida Console">array[ bar ] = bar; }<FONT
face="Lucida Console" color=#0000ff>Plot<FONT
face="Lucida Console">( array, <FONT face="Lucida Console"
color=#ff00ff>"bar"<FONT
face="Lucida Console">, colorRed );<FONT
face="Lucida Console" color=#0000ff>Plot<FONT
face="Lucida Console">( <FONT face="Lucida Console"
color=#0000ff>BarIndex(),
<FONT face="Lucida Console"
color=#ff00ff>"barindex"<FONT
face="Lucida Console">, colorBlue );<FONT
color=#0000ff>_TRACE(<FONT
color=#ff00ff>"#End");
<FONT
face=Tahoma><FONT face=Arial
color=#0000ff>
<FONT
face=Tahoma><SPAN
class=406480511-25072004>
<FONT
face=Tahoma><SPAN
class=406480511-25072004> -----Original
Message-----From: Tomasz Janeczko
[mailto:amibroker@xxxxxx]Sent: Sunday, July 25, 2004 3:40
AMTo: amibroker@xxxxxxxxxxxxxxxSubject: Re:
[amibroker] Looping within QuickAFL boundsImportance:
High
Herman,
You do not do worry about it or handle it
by yourself.
AmiBroker does it for you.
for(bar=0; bar<barcount; bar++) { ....
}
does not waste any cycles,
Try it:
array = 0;
for(bar=0; bar<barcount; bar++)
{
array[ bar ] =
bar;
}
Plot( array, "bar", colorRed
);
Plot( BarIndex(), "barindex", colorBlue
);
This because array item 0 already
is the first bar used by quick AFL (not the first bar in your data
set)
and (barcount-1) is a last
array item of quickafl (not the last bar in your data
set).
I have mentioned it that barcount is a
number of bars (items) in the array which may be
smaller.
<TABLE cellSpacing=0
cellPadding=0 width=529 border=0 x:str>
<TD class=xl24
width=97 height=17>Bar
Index
<TD class=xl24
align=right width=32 x:num><FONT face="Arial CE"
size=2>0
<TD class=xl24
align=right width=28 x:num><FONT face="Arial CE"
size=2>1
<TD class=xl24
align=right width=31 x:num><FONT face="Arial CE"
size=2>2
<TD class=xl24
align=right width=28 x:num><FONT face="Arial CE"
size=2>3
<TD class=xl24
align=right width=30 x:num><FONT face="Arial CE"
size=2>4
<TD class=xl24
align=right width=32 x:num><FONT face="Arial CE"
size=2>5
<TD class=xl24
align=right width=29 x:num><FONT face="Arial CE"
size=2>6
<TD class=xl24
align=right width=37 x:num><FONT face="Arial CE"
size=2>7
<TD class=xl26
align=right width=36 x:num><FONT face="Arial CE"
size=2>8
<TD class=xl24
align=right width=35 x:num><FONT face="Arial CE"
size=2>9
<TD class=xl24
align=right width=40 x:num><FONT face="Arial CE"
size=2>10
<TD class=xl24
align=right width=32 x:num><FONT face="Arial CE"
size=2>11
<TD class=xl24
align=right width=42 x:num><FONT face="Arial CE"
size=2>12
<TD class=xl25
height=17>Array element
<TD
><FONT
face="Arial CE" size=2>
<TD
><FONT
face="Arial CE" size=2>
<TD
><FONT
face="Arial CE" size=2>
<TD
><FONT
face="Arial CE" size=2>
<TD class=xl25
align=right x:num>0
<TD class=xl25
align=right x:num>1
<TD class=xl25
align=right x:num>2
<TD class=xl25
align=right x:num>3
<TD class=xl26
align=right x:num>4
<TD class=xl25
align=right x:num>5
<TD
>
<TD
>
<TD
>
As you can see in the picture above when
QuickAFL is on, BarCount variable will give you 6 in that
case
(the number of items in the array). So if
you will iterate from 0 to 5 you will access only visible
items automatically.
<FONT face=Arial
size=2>
So writing
for(bar=0; bar<barcount; bar++) you are already accessing
only what is necessary, not more.
Please note that the very first exectution
after clicking "APPLY" in Indicator Builder uses always *ALL* bars
because
it needs to analyse your code and its
requirements. Only subsequent executions use QuickAFL (less
bars).
Best regards,Tomasz
Janeczkoamibroker.com
<BLOCKQUOTE
>
----- Original Message -----
<DIV
>From:
Herman van den
Bergen
To: <A
title=amibroker@xxxxxxxxxxxxxxx
href="">AmiBroker YahooGroups
Sent: Sunday, July 25, 2004 2:38
AM
Subject: [amibroker] Looping
within QuickAFL bounds
<SPAN
class=437013000-25072004>Hello,
<SPAN
class=437013000-25072004>
would
anybody have figured out how to restrict a loop to the same range as
QuickAFL. Normally is use loops like:
<SPAN
class=437013000-25072004>for(bar=0; bar<barcount; bar++) {
.... }
<SPAN
class=437013000-25072004>
However
this is wasting a lot of cycles, especially when working with about
100,000 minute bars of which only the displayed segment (about 1%
of the data) is important. <SPAN
class=437013000-25072004>For use with QuickAFL ON, can anybody
provide the code to define:
<SPAN
class=437013000-25072004>FirstBarUsedByQuickAFL =
?
<SPAN
class=437013000-25072004>LastBarUsedByQuickAFL =
?
<SPAN
class=437013000-25072004>so that I can make the loop like
so:
<SPAN
class=437013000-25072004>for( bar = FirstBarUsedByQuickAFL; bar
<= LastBarUsedByQuickAFL; Bar++ ) { ....
}
Many
thanks,
<SPAN
class=437013000-25072004>herman.Check
AmiBroker web page at:<A
href="">http://www.amibroker.com/Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Check AmiBroker web page at:<A
href="">http://www.amibroker.com/Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Check AmiBroker web page
at:<A
href="">http://www.amibroker.com/Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Check AmiBroker web page at:<A
href="">http://www.amibroker.com/Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Check AmiBroker web page
at:<A
href="">http://www.amibroker.com/Check
group FAQ at: <A
href="">http://groups.yahoo.com/group/amibroker/files/groupfaq.html
Check AmiBroker web page at:
http://www.amibroker.com/
Check group FAQ at: http://groups.yahoo.com/group/amibroker/files/groupfaq.html
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