Struct Exponential 

pub struct Exponential { /* private fields */ }

Exponential distribution with rate parameter λ.

Models the time between events in a Poisson process. The rate λ > 0 determines the expected frequency; the mean is 1/λ.

Examples

use u_numflow::distributions::Exponential;

let exp = Exponential::new(0.5).unwrap();
assert!((exp.mean() - 2.0).abs() < 1e-10);
assert!((exp.cdf(2.0) - (1.0 - (-1.0_f64).exp())).abs() < 1e-10);

Implementations

impl Exponential

pub fn new(rate: f64) -> Result<Self, DistributionError>

Creates a new Exponential distribution with the given rate λ.

Returns an error if λ ≤ 0 or λ is not finite.

pub fn rate(&self) -> f64

Rate parameter λ.

pub fn mean(&self) -> f64

Mean = 1/λ.

pub fn variance(&self) -> f64

Variance = 1/λ².

pub fn pdf(&self, x: f64) -> f64

PDF: f(x) = λ exp(−λx) for x ≥ 0, 0 otherwise.

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

CDF: F(x) = 1 − exp(−λx) for x ≥ 0, 0 otherwise.

pub fn quantile(&self, p: f64) -> Option<f64>

Quantile (inverse CDF): x = −ln(1−p)/λ.

Returns None if p is not in [0, 1].

pub fn hazard_rate(&self) -> f64

Hazard rate (failure rate): h(x) = λ (constant).

pub fn survival(&self, x: f64) -> f64

Survival function: S(x) = exp(−λx).

Trait Implementations

impl Clone for Exponential

fn clone(&self) -> Exponential

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Exponential

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

Formats the value using the given formatter.

impl Copy for Exponential