File Coverage

lib/Spreadsheet/Engine/Function/VAR.pm

Criterion	Covered	Total	%
statement	21	21	100.0
branch	4	4	100.0
condition			n/a
subroutine	6	6	100.0
pod	2	2	100.0
total	33	33	100.0

package Spreadsheet::Engine::Function::VAR;

use strict;
use warnings;

use base 'Spreadsheet::Engine::Fn::series';

sub calculate {
  return sub {
    my ($in, $A) = @_;
    return $A = { mk1 => $in->value, sk1 => 0, count => 1 }
      unless defined $A;

    my $diff = $in->value - $A->{mk1};
    $A->{mk}  = $A->{mk1} + $diff / ++$A->{count};
    $A->{sk}  = $A->{sk1} + $diff * ($in->value - $A->{mk});
    $A->{sk1} = $A->{sk};
    $A->{mk1} = $A->{mk};
    return $A;
  };
}

sub result_from {
  my ($self, $A) = @_;
  die Spreadsheet::Engine::Error->div0 unless $A->{count} > 1;
  return $A->{sk} / ($A->{count} - 1);
}

1;

__END__