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.IX Title "..::lib::Smokeping::matchers::ExpLoss 3"
.TH ..::lib::Smokeping::matchers::ExpLoss 3 2024-02-04 2.8.2 SmokePing
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.SH NAME
Smokeping::matchers::ExpLoss \- exponential weighting matcher for packet loss
with RMON\-like thresholds
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Match against exponential weighted average of last samples, thus new values 
are more valuable as old ones. Two thresholds \- rising and falling \- produce 
hysteresis loop like in RMON alert subsystem. If the average reaches the 
"rising" threshold, matcher go to the "match" state and hold It until the 
average drops under the "falling" threshold.
.PP
Call the matcher with the following sequence:
.PP
.Vb 3
\& type = matcher
\& pattern = ExpLoss(hist => <hist>, rising=><rising> \e
\&                  [,falling => <falling>] [,skip=><stat>] [,fast=><fast>])
.Ve
.PP
Arguments:
 hist    \- number of samples to weight against; weight will be disposed with
           exponential decreasing manner from newest to oldest, so that the
           oldest sample would have 1% significance;
 rising  \- rising threshold for packet loss, 0\-100%
 falling \- falling threshold for packet loss, default is <rising>
 skip    \- skip <skip> number of samples after startup before "fire" alerts.
 fast    \- use <fast> samples for fast transition: if the values of last <fast>
           samples more then <rising> \- take "match" state, if less then
           <falling> \- take "no match" state.
.PP
Note:
 If the actual history is less then <hist> value then this value is taken 
 as the actual history.
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright (c) 2008 Veniamin Konoplev
.PP
Developed in cooperation with EU EGEE project
.SH LICENSE
.IX Header "LICENSE"
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
.PP
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
.PP
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
.SH AUTHOR
.IX Header "AUTHOR"
Veniamin Konoplev <vkonoplev@acm.org>