Statistics::Descriptive::Smoother::Weightedexponential (3)

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NAME

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 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:

*

t = index in the series

*

S(t) = smoothed series value at position t

*

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.

*

X(t) = unsmoothed series value at position t

METHODS

$stats->get_smoothed_data();

Returns a copy of the smoothed data array.

AUTHOR

COPYRIGHT

LICENSE

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.