Function malachite_base::strings::random::random_strings

source · [−]

pub fn random_strings(
    seed: Seed, 
    mean_length_numerator: u64, 
    mean_length_denominator: u64
) -> StringsFromCharVecs<RandomVecs<char, GeometricRandomNaturalValues<u64>, RandomCharRange>>ⓘNotable traits for StringsFromCharVecs<I>impl<I: Iterator<Item = Vec<char>>> Iterator for StringsFromCharVecs<I>    type Item = String;

Expand description

Generates random Strings.

The lengths of the Strings 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.

$$ P((c_0, c_1, \ldots, c_{n-1})) = \frac{m^n}{1112064^n(m+1)^{n+1}} $$

Expected complexity per iteration

$T(n) = O(m)$

$M(n) = O(m)$

where $T$ is time, $M$ is additional memory, and $m$ is mean_length_numerator / mean_length_denominator.

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

extern crate itertools;

use itertools::Itertools;
use malachite_base::random::EXAMPLE_SEED;
use malachite_base::strings::random::random_strings;

let ss = random_strings(EXAMPLE_SEED, 4, 1).take(10).collect_vec();
assert_eq!(
    ss.iter().map(|cs| cs.as_str()).collect_vec().as_slice(),
    &[
        "",
        "\u{81355}\u{a331d}\u{b707b}\u{1354b}\u{b16ac}𣙘\u{67377}\u{4aaa4}\u{a6d6e}\u{45616}\
        \u{7725f}\u{41e2d}\u{d6b59}\u{de165}",
        "\u{c2d29}\u{695af}\u{98fd7}\u{10ca51}",
        "\u{bec46}\u{c0bec}\u{cb677}\u{71318}",
        "\u{755e1}",
        "",
        "𫮜\u{a2f84}柂\u{f5560}\u{6737b}",
        "\u{8442e}\u{a6883}",
        "\u{49cf2}\u{32d2b}\u{1e6e5}\u{1084bd}",
        ""
    ]
);