Function lattice_qcd_rs::statistics::covariance_par_iter_val

pub fn covariance_par_iter_val<It1, It2, T>(
    data_1: It1,
    data_2: It2
) -> Option<T>where
    T: Clone + Div<f64, Output = T> + Sum<T> + Sum<It1::Item> + Send + Mul<T, Output = T> + Sub<T, Output = T> + Zero,
    It1: IndexedParallelIterator<Item = T> + Clone,
    It2: IndexedParallelIterator<Item = T> + Clone,

Computes the covariance between two [rayon::iter::IndexedParallelIterator] by value. Returns None if the par iters are not of the same length.

The alternative for iterators returning references is covariance_par_iter.

Example

use lattice_qcd_rs::statistics::covariance_par_iter_val;
use rayon::prelude::*;

fn expensive_computation(input: &f64) -> f64 {
    input + 1_f64
}

let vec = vec![1_f64, 2_f64, 3_f64, 4_f64];
let vec_2 = vec![1_f64, 2_f64, 3_f64];

let cov = covariance_par_iter_val(
    vec.par_iter().map(|input| expensive_computation(input)),
    vec_2.par_iter().map(|input| expensive_computation(input)),
);
assert!(cov.is_none());

let vec = vec![1_f64, 1_f64, 1_f64, 1_f64];
let vec_2 = vec![1_f64, 1_f64, 1_f64, 1_f64];

let cov = covariance_par_iter_val(
    vec.par_iter().map(|input| expensive_computation(input)),
    vec_2.par_iter().map(|input| expensive_computation(input)),
);
assert_eq!(cov, Some(0_f64));