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Thank
you again, TJ. The learning process never ends with AB. Thanks to your help my
code is running a few hundred times faster now... this means I can even add more
frills :-) Sure proves it is worthwhile to, once code is working, work through
it once more to try to optimize it.
<FONT face=Arial color=#0000ff
size=2>
Where
else could one find this kind of technical support? I'll tell you: no where! it
is unique!
<FONT face=Arial color=#0000ff
size=2>
best
regards,
<FONT face=Arial color=#0000ff
size=2>herman.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Tahoma
size=2>-----Original Message-----From: Tomasz Janeczko
[mailto:amibroker@xxxxxx]Sent: Sunday, July 25, 2004 1:24
PMTo: amibroker@xxxxxxxxxxxxxxxSubject: Re: [amibroker]
Looping within QuickAFL boundsImportance: High
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 = "<FONT
color=#000000>+bi[0<FONT
color=#000000>]+" End bar = "<FONT
color=#000000>+bi[BarCount<FONT
color=#000000>-1] +
" NumBars =" +
BarCount,
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
<FONT face=Arial color=#0000ff
size=2>TJ, i did NOT use Apply. I emailed test result emailed to you
privately for your persusal.
<FONT face=Arial color=#0000ff
size=2>
<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. <FONT face=Arial
size=2>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:<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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