# FreeBSD Manual Pages

```Statistics::DescriptiSUsersContributediPerleDocumentationNAME
Statistics::Descriptive::Smoother::Weigthedexponential -	Implement
weighted	exponential smoothing

SYNOPSIS
use Statistics::Descriptive::Smoother;
my \$smoother =	Statistics::Descriptive::Smoother->instantiate({
method   => 'weightedexponential',
coeff	   => 0.5,
data	   => [1, 2, 3,	4, 5],
samples  => [110, 120, 130, 140, 150],
});
my @smoothed_data = \$smoother->get_smoothed_data();

DESCRIPTION
This module implement the weighted exponential smoothing	algorithm to
smooth the trend	of a series of statistical data.

This algorithm can help to control large	swings in the unsmoothed data
that arise from small samples for those data points.

The algorithm implements	the following formula:

W(0) = N(0)

W(t) = (	W(t-1) * CoeffA	+ N(t) * CoeffB	) / (CoeffA + CoeffB)

CoeffA =	C * ( W(t-1) / (W(t-1) + N(t) )	)

CoeffB =	(1 - C)	* ( N(t) * (W(t-1) + N(t)) )

S(t) = (S(t-1)*CoeffA + X(t)*CoeffB) / (CoeffA +	CoeffB)

where:

o  t = index in the series

o  S(t) = smoothed series value at position t

o  C = smoothing	coefficient. Value in the [0;1]	range. 0 means that
the series is	not smoothed at	all, while 1 the series	is universally
equal	to the initial unsmoothed value.

o  X(t) = unsmoothed series value at position t

METHODS
\$stats->get_smoothed_data();
Returns a copy of the smoothed data	array.

AUTHOR
Fabio Ponciroli

Permission is hereby granted, free of charge, to	any person obtaining a
copy of this software and associated documentation files	(the
"Software"), to deal in the Software without restriction, including
without limitation the rights to	use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished	to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or	substantial portions of	the Software.

THE SOFTWARE IS PROVIDED	"AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO	THE WARRANTIES OF
MERCHANTABILITY,	FITNESS	FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR	COPYRIGHT HOLDERS BE LIABLE FOR	ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN	ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM,	OUT OF OR IN CONNECTION	WITH THE
SOFTWARE	OR THE USE OR OTHER DEALINGS IN	THE SOFTWARE.

perl v5.24.1	     Statistics::Descriptive::Smoother::Weightedexponential(3)
```

NAME | SYNOPSIS | DESCRIPTION | METHODS | AUTHOR | COPYRIGHT | LICENSE

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