Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for an old version of boost. Click here for the latest Boost documentation.

Struct template lazy_variance_impl

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

Synopsis

// In header: <boost/accumulators/statistics_fwd.hpp>

template<typename Sample, typename MeanFeature> 
struct lazy_variance_impl : public accumulator_base {
  // construct/copy/destruct
  lazy_variance_impl(dont_care);

  // public member functions
  template<typename Args> result_type result(Args const &) const;
  template<typename Archive> void serialize(Archive &, const unsigned int);
};

Description

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

Equation 1.19.

where

Equation 1.20.

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;

template<typename Archive> 
  void serialize(Archive & ar, const unsigned int file_version);