## Struct template lazy_variance_impl

boost::accumulators::impl::lazy_variance_impl — Lazy calculation of variance.

## Synopsis

template<typename Sample, typename MeanFeature>
struct lazy_variance_impl {
typedef numeric::functional::average< Sample, std::size_t >::result_type result_type;
lazy_variance_impl(dont_care);
template<typename Args> result_type result(Args const &) const;
};

## Description

Default sample variance implementation based on the second moment moment<2>, mean and count.

where

is the estimate of the sample mean and is the number of samples.

###
`lazy_variance_impl`

public
construct/copy/destruct

lazy_variance_impl(dont_care);

###
`lazy_variance_impl`

public member functions

template<typename Args> result_type result(Args const & args) const;