Struct average::Average

pub struct Average { /* fields omitted */ }

Estimate the arithmetic mean and the variance of a sequence of numbers ("population").

This can be used to estimate the standard error of the mean.

Everything is calculated iteratively using constant memory, so the sequence of numbers can be an iterator. The used algorithms try to avoid numerical instabilities.

Example

use average::Average;

let a: Average = (1..6).map(Into::into).collect();
println!("The average is {} ± {}.", a.mean(), a.error());

Methods

impl Average

fn new() -> Average

Create a new average estimator.

fn add(&mut self, sample: f64)

Add an element sampled from the population.

fn is_empty(&self) -> bool

Determine whether the samples are empty.

fn mean(&self) -> f64

Estimate the mean of the population.

fn len(&self) -> u64

Return the number of samples.

fn sample_variance(&self) -> f64

Calculate the sample variance.

This is an unbiased estimator of the variance of the population.

fn population_variance(&self) -> f64

Calculate the population variance of the sample.

This is a biased estimator of the variance of the population.

fn error(&self) -> f64

Estimate the standard error of the mean of the population.

fn merge(&mut self, other: &Average)

Merge another sample into this one.

Example

use average::Average;

let sequence: &[f64] = &[1., 2., 3., 4., 5., 6., 7., 8., 9.];
let (left, right) = sequence.split_at(3);
let avg_total: Average = sequence.iter().map(|x| *x).collect();
let mut avg_left: Average = left.iter().map(|x| *x).collect();
let avg_right: Average = right.iter().map(|x| *x).collect();
avg_left.merge(&avg_right);
assert_eq!(avg_total.mean(), avg_left.mean());
assert_eq!(avg_total.sample_variance(), avg_left.sample_variance());

Trait Implementations

impl Debug for Average

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Clone for Average

fn clone(&self) -> Average

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for Average

fn default() -> Average

Returns the "default value" for a type.

impl FromIterator<f64> for Average

fn from_iter<T>(iter: T) -> Average where
    T: IntoIterator<Item = f64>, 

Creates a value from an iterator.