Struct ChiSquare 

pub struct ChiSquare { /* private fields */ }

Chi-Square Distribution

The Chi-Square distribution represents the distribution of the sum of squares of 𝑟 independent standard normal random variables.

Examples

// Create a new Chi-Square distribution with specified seeds
let mut chi_square = rand_simple::ChiSquare::new([1192_u32, 765_u32, 1543_u32, 2003_u32]);

// Output the string representation of the distribution
assert_eq!(format!("{chi_square}"), "χ^2(Degree of Freedom parameter) = χ^2(1)");

// Generate a random number following the distribution with initial settings
println!("For initial settings, returns a random number following Chi-Square distribution with 1 degree of freedom -> {}", chi_square.sample());

// Change the parameters of the random variable
let degree_of_freedom: u64 = 2_u64;
let result: Result<u64, &str> = chi_square.try_set_params(degree_of_freedom);

// Output the updated string representation of the distribution
assert_eq!(format!("{chi_square}"), "χ^2(Degree of Freedom parameter) = χ^2(2)");

// Generate a random number following the distribution with updated parameters
println!("Generates a random number following Chi-Square distribution with {} degrees of freedom -> {}", degree_of_freedom, chi_square.sample());

Implementations

impl ChiSquare

pub fn new(seeds: [u32; 4]) -> Self

Chi-Square Distribution Constructor

This constructor initializes a new instance of the Chi-Square distribution with the given seeds for random number generation.

• _seed - Seeds for random number generation

Examples

// Create a new Chi-Square distribution with specified seeds
let mut chi_square = rand_simple::ChiSquare::new([1192_u32, 765_u32, 1543_u32, 2003_u32]);

pub fn sample(&mut self) -> f64

Generates a Random Number

This method generates a random number based on the Chi-Square distribution algorithm.

Algorithm 3.79:

• When the degree of freedom is 2, the distribution becomes an Exponential distribution Exp(2).
• For r > 1, it generates a random number X following the Gamma distribution Γ(r_div2, 2).
• For r = 1, it generates a random number Y following the Gamma distribution Γ(3/2, 2), then generates a uniform random number U in the interval (0, 1), and finally calculates X = 2YU^2.

Returns

The generated random number.

pub fn try_set_params(&mut self, degree_of_freedom: u64) -> Result<u64, &str>

Sets the Parameters of the Probability Variable

This method allows for changing the parameters of the Chi-Square distribution.

Arguments

• degree_of_freedom - The degree of freedom (r) parameter of the distribution.

Returns

Returns Ok(degree_of_freedom) if successful, else returns an error message.

Trait Implementations

impl Display for ChiSquare

Formatter for Displaying the Chi-Square Distribution

This implementation enables the display of Chi-Square distributions in macros like print!.

Arguments

• f - The formatter to write the formatted string to.

Returns

Returns core::fmt::Result.

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

Formats the value using the given formatter.