Function malachite_base::vecs::random::random_ordered_unique_vecs

pub fn random_ordered_unique_vecs<I: Iterator>(
    seed: Seed,
    xs_gen: &dyn Fn(Seed) -> I,
    mean_length_numerator: u64,
    mean_length_denominator: u64
) -> RandomOrderedUniqueVecs<I::Item, GeometricRandomNaturalValues<u64>, I> where
    I::Item: Ord,

Generates random Vecs using elements from an iterator, where the Vecs have no repeated elements, and the elements are in ascending order.

The lengths of the Vecs are sampled from a geometric distribution with a specified mean $m$, equal to mean_length_numerator / mean_length_denominator. $m$ must be greater than 0.

Strictly speaking, the input iterator must generate infinitely many distinct elements. In practice it only needs to generate $k$ distinct elements, where $k$ is the largest length actually sampled from the geometric distribution. For example, if mean_length_numerator / mean_length_denominator is significantly lower than 256, then it’s ok to use random_unsigneds::<u8>.

$$ P((x_i)_{i=0}^{n-1}) = n!P_g(n)\prod_{i=0}^{n-1}P(x_i), $$ where $P_g(n)$ is the probability function described in geometric_random_unsigneds.

xs_gen must be infinite.

Panics

Panics if mean_length_numerator or mean_length_denominator are zero, or, if after being reduced to lowest terms, their sum is greater than or equal to $2^{64}$.

Examples

use itertools::Itertools;
use malachite_base::num::random::random_primitive_ints;
use malachite_base::random::EXAMPLE_SEED;
use malachite_base::vecs::random::random_ordered_unique_vecs;

let xs = random_ordered_unique_vecs(EXAMPLE_SEED, &random_primitive_ints::<u8>, 4, 1);
let values = xs.take(20).collect_vec();
assert_eq!(
    values.iter().map(Vec::as_slice).collect_vec().as_slice(),
    &[
        &[][..],
        &[11, 32, 38, 85, 134, 136, 162, 166, 177, 200, 203, 217, 223, 235],
        &[30, 90, 218, 234],
        &[9, 106, 204, 216],
        &[151],
        &[],
        &[78, 91, 97, 213, 253],
        &[39, 191],
        &[170, 175, 232, 233],
        &[],
        &[2, 22, 35, 114, 198, 217],
        &[],
        &[],
        &[17, 25, 32, 65, 79, 114, 121, 144, 148, 173, 222],
        &[52, 69, 73, 91, 115, 137, 153, 178],
        &[],
        &[34, 95, 112],
        &[],
        &[106, 130, 167, 168, 197],
        &[86, 101, 122, 150, 172, 177, 207, 218, 221]
    ]
);