[asterisk-bugs] [Asterisk 0012781]: Queue holdtime smoothing filter is not boxcar (FIR), but exponential average (IIR).

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=12781 
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Reported By:                davidw
Assigned To:                putnopvut
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Project:                    Asterisk
Issue ID:                   12781
Category:                   Applications/app_queue
Reproducibility:            always
Severity:                   text
Priority:                   normal
Status:                     closed
Asterisk Version:           1.4.20.1 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
Resolution:                 fixed
Fixed in Version:           
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Date Submitted:             06-03-2008 13:01 CDT
Last Modified:              06-17-2008 10:51 CDT
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Summary:                    Queue holdtime smoothing filter is not boxcar (FIR),
but exponential average (IIR).
Description: 
The comment for recalc_holdtime says that it implements a recursive boxcar
algorithm.  Even with the "recursive" qualifier, boxcar averaging refers to
simple rolling average filters, which are finite impulse response ones. 
The filter that recalc_holdtime actually implements is an exponential
average, which is an infinite impulse response filter.


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---------------------------------------------------------------------- 
 svnbot - 06-17-08 10:51  
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Repository: asterisk
Revision: 123276

_U  branches/1.6.0/
U   branches/1.6.0/apps/app_queue.c

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r123276 | mmichelson | 2008-06-17 10:51:21 -0500 (Tue, 17 Jun 2008) | 28
lines

Merged revisions 123275 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/trunk

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r123275 | mmichelson | 2008-06-17 10:57:43 -0500 (Tue, 17 Jun 2008) | 20
lines

Merged revisions 123274 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.4

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r123274 | mmichelson | 2008-06-17 10:56:55 -0500 (Tue, 17 Jun 2008) | 12
lines

davidw pointed out that the holdtime calculation used by
app_queue does not use "boxcar" filtering as the comments
say. The term "boxcar" means that the number of samples used
to calculate stays constant, with new samples replacing the
oldest ones. The queue holdtime calculation uses all holdtime
samples collected since the queue was loaded, so the comment
has been changed to be accurate.

(closes issue http://bugs.digium.com/view.php?id=12781)
Reported by: davidw


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http://svn.digium.com/view/asterisk?view=rev&revision=123276 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
06-17-08 10:51  svnbot         Checkin                                      
06-17-08 10:51  svnbot         Note Added: 0088811                          
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