Struct andys_morning_stroll::Expectation

pub struct Expectation<T: RandomWalk> {
    pub freq_map: HashMap<u32, u32>,
    pub cnt: u32,
    /* private fields */
}

A struct to calculate the expected length of a random walk, for any type T: RandomWalk. We will use this to calculate the expected values of walks on our Football and KitchenFloor types.

Fields

freq_map: HashMap<u32, u32>

A map from walk lengths to the frequency of occurences of walks of that length.

cnt: u32

Count of the number of runs executed so far.

Implementations

impl<T: RandomWalk> Expectation<T>

pub fn new(walker: T) -> Self

Create a new expectation calculator.

pub fn calculate(&mut self, src: T::State, tgt: T::State, runs: u32) -> f32

Run the expectation computation. Internally, this calls walker.walk which does not take a limit cut-off for walk lengths. Therefore, this function could take a long time if walks can be extremely long or even diverege to infinity.

pub fn calculate_with_limit( &mut self, src: T::State, tgt: T::State, runs: u32, limit: u32 ) -> f32

Same as calculate but takes a limit argument which is passed to RandomWalk::walk_until_limit in order to ensure the function terminates, ideally in a reasonable time.