Struct BranchingProcess 

pub struct BranchingProcess {
    pub z0: usize,
    pub mean_offspring: f64,
    /* private fields */
}

Galton-Watson branching process.

Each individual in generation n independently produces a random number of offspring in generation n+1 according to an offspring distribution.

Fields

z0: usize

Initial population Z(0).

mean_offspring: f64

Mean offspring per individual.

Implementations

impl BranchingProcess

pub fn poisson(z0: usize, lambda: f64, seed: u64) -> Self

Creates a new Galton-Watson process with Poisson offspring.

pub fn geometric(z0: usize, p: f64, seed: u64) -> Self

Creates a new process with Geometric offspring.

pub fn bernoulli(z0: usize, p: f64, seed: u64) -> Self

Creates a new process with Bernoulli offspring.

pub fn simulate(&self, n_generations: usize) -> Vec<usize>

Simulate the process for n_generations generations.

Returns population sizes Z(0), Z(1), …, Z(n_generations).

pub fn extinction_probability(&self) -> f64

Theoretical extinction probability for Poisson offspring.

For Poisson(lambda) offspring:

• If lambda <= 1: extinction probability = 1.
• If lambda > 1: extinction probability = q where q = exp(lambda*(q-1)). Solved iteratively.

pub fn mc_extinction_probability( &self, n_paths: usize, n_generations: usize, ) -> f64

Estimate extinction probability by Monte Carlo simulation.