Struct Probability 

pub struct Probability { /* private fields */ }

A validated probability value in the closed interval [0, 1].

Implementations

impl Probability

pub const fn new(value: f64) -> Probability

Creates a probability without validation.

pub const fn try_new(value: f64) -> Result<Probability, ProbabilityError>

Creates a probability from a finite value in [0, 1].

Errors

Returns ProbabilityError::NonFiniteProbability when value is NaN or infinite, and ProbabilityError::ProbabilityOutOfRange when value is outside [0, 1].

Examples

use use_probability::{Probability, ProbabilityError};

let probability = Probability::try_new(0.25)?;
assert_eq!(probability, Probability::new(0.25));

assert!(matches!(
    Probability::try_new(1.5),
    Err(ProbabilityError::ProbabilityOutOfRange(1.5))
));

pub fn from_fraction( part: u64, total: u64, ) -> Result<Probability, ProbabilityError>

Creates a probability from part / total.

Errors

Returns ProbabilityError::ZeroTotal when total == 0, and ProbabilityError::PartExceedsTotal when part > total.

Examples

use use_probability::Probability;

let probability = Probability::from_fraction(1, 4)?;
assert!((probability.value() - 0.25).abs() < 1.0e-12);

pub const fn validate(self) -> Result<Probability, ProbabilityError>

Validates that an existing probability remains normalized.

Errors

Returns the same error variants as Self::try_new.

pub const fn value(&self) -> f64

Returns the stored probability value.

pub const fn as_percentage(&self) -> f64

Returns the stored probability as a percentage.

pub const fn complement(self) -> Probability

Returns the complementary probability 1 - p.

pub const fn impossible() -> Probability

Returns the impossible event probability 0.

pub const fn certainty() -> Probability

Returns the certain event probability 1.

pub const fn intersection_independent(self, other: Probability) -> Probability

Returns the probability of two independent events both happening.

pub fn union_independent(self, other: Probability) -> Probability

Returns the probability of at least one of two independent events happening.

Trait Implementations

impl Clone for Probability

fn clone(&self) -> Probability

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Probability

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

Formats the value using the given formatter.

impl Default for Probability

fn default() -> Probability

Returns the “default value” for a type.

impl Display for Probability

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

Formats the value using the given formatter.

impl PartialEq for Probability

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Probability

fn partial_cmp(&self, other: &Probability) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Probability

impl StructuralPartialEq for Probability