Struct Erlang

Source

pub struct Erlang { /* private fields */ }

Expand description

Erlang Distribution

Represents a random variable following the Erlang distribution.

§Examples

// Create a new Erlang distribution with specified seeds
let mut erlang = rand_simple::Erlang::new([1192u32, 765u32, 1543u32]);

// Ensure the initial parameters are correctly set
assert_eq!(format!("{erlang}"), "Er(Shape parameter, Scale parameter) = Er(1, 1)");

// Generate a random number from the Erlang distribution
println!("Generating a random number following the standard Erlang distribution with shape parameter r = 1 and scale parameter θ = 1 -> {}", erlang.sample());

// Modify the parameters of the random variable
let shape: i64 = 2_i64;
let scale: f64 = 1.5_f64;
let result: Result<(i64, f64), &str> = erlang.try_set_params(shape, scale);

// Ensure the parameters are updated correctly
assert_eq!(format!("{erlang}"), "Er(Shape parameter, Scale parameter) = Er(2, 1.5)");

// Generate a random number from the modified Erlang distribution
println!("Generating a random number following the Erlang distribution with shape parameter r = {} and scale parameter θ = {} -> {}", shape, scale, erlang.sample());

Implementations§

Source §

impl Erlang

Source

pub fn new(seeds: [u32; 3]) -> Self

Constructor

Creates a new instance of the Erlang distribution with the provided seeds for random number generation. Seeds are adjusted internally to ensure uniqueness.

§Arguments

seeds - Seeds for random number generation. Adjusted internally to ensure uniqueness.

§Returns

A new instance of the Erlang distribution.

§Example

// Create a new Erlang distribution with specified seeds
let mut erlang = rand_simple::Erlang::new([1192u32, 765u32, 1543u32]);

Source

pub fn sample(&mut self) -> f64

Generate a random number.

This method calculates a random number using the standard gamma distribution.

§Returns

Returns a random number generated from the standard gamma distribution, multiplied by the scale parameter.

§Examples

let mut erlang = rand_simple::Erlang::new([1192u32, 765u32, 1543u32]);
let random_number = erlang.sample();
println!("Random number: {}", random_number);

Source

pub fn try_set_params( &mut self, shape: i64, scale: f64, ) -> Result<(i64, f64), &str>

Attempt to modify the parameters of the random variable.

shape - Shape parameter.
scale - Scale parameter.

§Arguments

shape - Shape parameter.
scale - Scale parameter.

§Returns

Returns a tuple (i64, f64) representing the modified parameters (shape, scale).

§Errors

Returns an error message if the provided parameters are invalid.

§Examples

let mut erlang = rand_simple::Erlang::new([1192u32, 765u32, 1543u32]);
assert_eq!(erlang.try_set_params(3, 0.5), Ok((3, 0.5)));
assert_eq!(erlang.try_set_params(0, 0.5), Err("The shape parameter is less than or equal to 0. The parameters of the random variable will remain unchanged."));
assert_eq!(erlang.try_set_params(1, -0.1), Err("The scale parameter is less than or equal to 0. The parameters of the random variable will remain unchanged."));