File Coverage

blib/lib/Statistics/Descriptive/Smoother/Weightedexponential.pm

Criterion	Covered	Total	%
statement	48	48	100.0
branch	2	2	100.0
condition	1	2	50.0
subroutine	9	9	100.0
pod	1	1	100.0
total	61	62	98.3

package Statistics::Descriptive::Smoother::Weightedexponential;
$Statistics::Descriptive::Smoother::Weightedexponential::VERSION = '3.0800';
use strict;
use warnings;

use Carp qw/ carp /;
use parent 'Statistics::Descriptive::Smoother';

sub _new
{
    my ( $class, $args ) = @_;

    if ( scalar @{ $args->{data} } != scalar @{ $args->{samples} } )
    {
        carp("Number of data values and samples need to be the same\n");
        return;
    }

    return bless $args || {}, $class;
}

# The name of the variables used in the code refers to the explanation in the pod
sub get_smoothed_data
{
    my ($self) = @_;

    my ( @smoothed_values, @Wts );

    # W(0) = N(0)
    push @Wts, @{ $self->{samples} }[0];

    # S(0) = X(0)
    push @smoothed_values, @{ $self->{data} }[0];
    my $C = $self->get_smoothing_coeff();

    foreach my $idx ( 1 .. ( $self->{count} - 1 ) )
    {
        my $Xt   = $self->{data}->[$idx];
        my $Nt   = $self->{samples}->[$idx];
        my $St_1 = $smoothed_values[-1];
        my $Wt_1 = $Wts[-1];

        push @Wts, $self->_get_Wt( $Wt_1, $Nt );

        my $coeff_a = $self->_get_coeff_A( $Wt_1, $Nt );
        my $coeff_b = $self->_get_coeff_B( $Wt_1, $Nt );

        my $smoothed_value =
            ( $St_1 * $coeff_a + $Xt * $coeff_b ) / ( $coeff_a + $coeff_b );
        push @smoothed_values, $smoothed_value;
    }
    return @smoothed_values;
}

sub _get_Wt
{
    my ( $self, $Wt_1, $Nt ) = @_;

    my $C       = $self->get_smoothing_coeff();
    my $coeff_a = $self->_get_coeff_A( $Wt_1, $Nt );
    my $coeff_b = $self->_get_coeff_B( $Wt_1, $Nt );

    return ( ( $Wt_1 * $coeff_a + $Nt * $coeff_b ) / ( $coeff_a + $coeff_b ) );
}

sub _get_coeff_A
{
    my ( $self, $Wt_1, $Nt ) = @_;

    my $C = $self->get_smoothing_coeff();
    return $C * ( $Wt_1 / ( $Wt_1 + $Nt ) );
}

sub _get_coeff_B
{
    my ( $self, $Wt_1, $Nt ) = @_;

    my $C = $self->get_smoothing_coeff();
    return ( 1 - $C ) * ( $Nt / ( $Nt + $Wt_1 ) );
}

1;

__END__