Struct statrs::distribution::Geometric

pub struct Geometric { /* fields omitted */ }

Implements the Geometric distribution

Examples

use statrs::distribution::{Geometric, Discrete};
use statrs::statistics::Distribution;

let n = Geometric::new(0.3).unwrap();
assert_eq!(n.mean().unwrap(), 1.0 / 0.3);
assert_eq!(n.pmf(1), 0.3);
assert_eq!(n.pmf(2), 0.21);

Implementations

impl Geometric

pub fn new(p: f64) -> Result<Geometric>

Constructs a new shifted geometric distribution with a probability of p

Errors

Returns an error if p is not in (0, 1]

Examples

use statrs::distribution::Geometric;

let mut result = Geometric::new(0.5);
assert!(result.is_ok());

result = Geometric::new(0.0);
assert!(result.is_err());

pub fn p(&self) -> f64

Returns the probability p of the geometric distribution

Examples

use statrs::distribution::Geometric;

let n = Geometric::new(0.5).unwrap();
assert_eq!(n.p(), 0.5);

Trait Implementations

impl Clone for Geometric

fn clone(&self) -> Geometric

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Geometric

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Discrete<u64, f64> for Geometric

fn pmf(&self, x: u64) -> f64

Calculates the probability mass function for the geometric distribution at x

Formula

(1 - p)^(x - 1) * p

fn ln_pmf(&self, x: u64) -> f64

Calculates the log probability mass function for the geometric distribution at x

Formula

ln((1 - p)^(x - 1) * p)

impl DiscreteCDF<u64, f64> for Geometric

fn cdf(&self, x: u64) -> f64

Calculates the cumulative distribution function for the geometric distribution at x

Formula

1 - (1 - p) ^ (x + 1)

fn inverse_cdf(&self, p: T) -> K

Due to issues with rounding and floating-point accuracy the default implementation may be ill-behaved Specialized inverse cdfs should be used whenever possible.

impl Distribution<f64> for Geometric

fn mean(&self) -> Option<f64>

Returns the mean of the geometric distribution

Formula

1 / p

fn variance(&self) -> Option<f64>

Returns the standard deviation of the geometric distribution

Formula

(1 - p) / p^2

fn entropy(&self) -> Option<f64>

Returns the entropy of the geometric distribution

Formula

(-(1 - p) * log_2(1 - p) - p * log_2(p)) / p

fn skewness(&self) -> Option<f64>

Returns the skewness of the geometric distribution

Formula

(2 - p) / sqrt(1 - p)

fn std_dev(&self) -> Option<T>

Returns the standard deviation, if it exists.

impl Distribution<f64> for Geometric

fn sample<R: Rng + ?Sized>(&self, r: &mut R) -> f64

Generate a random value of T, using rng as the source of randomness.

fn sample_iter<R>(self, rng: R) -> DistIter<Self, R, T> where
    R: Rng, 

Create an iterator that generates random values of T, using rng as the source of randomness.

impl Max<u64> for Geometric

fn max(&self) -> u64

Returns the maximum value in the domain of the geometric distribution representable by a 64-bit integer

Formula

2^63 - 1

impl Median<f64> for Geometric

fn median(&self) -> f64

Returns the median of the geometric distribution

Remarks

Formula

ceil(-1 / log_2(1 - p))

impl Min<u64> for Geometric

fn min(&self) -> u64

Returns the minimum value in the domain of the geometric distribution representable by a 64-bit integer

Formula

1

impl Mode<Option<u64>> for Geometric

fn mode(&self) -> Option<u64>

Returns the mode of the geometric distribution

Formula

1

impl PartialEq<Geometric> for Geometric

fn eq(&self, other: &Geometric) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Geometric) -> bool

This method tests for !=.

impl Copy for Geometric

impl StructuralPartialEq for Geometric