Function malachite_base::chars::random::graphic_weighted_random_char_range

pub fn graphic_weighted_random_char_range(
    seed: Seed, 
    a: char, 
    b: char, 
    p_numerator: u64, 
    p_denominator: u64
) -> WeightedGraphicRandomCharRange

Generates random chars in the half-open interval $[a, b)$, weighting graphic and non-graphic chars separately.

See char_is_graphic for the definition of a graphic char.

Let $n_p$ be p_numerator and $d_p$ be p_denominator, and let $p = p_n/p_d$.

The set of graphic chars in the specified range is selected with probability $p$, and the set of non-graphic chars in the range with probability $1-p$. Then, a char is selected uniformly from the appropriate set.

$a$ must be less than $b$. Furthermore, $[a, b)$ must contain both graphic and non-graphic chars. This function cannot create a range that includes char::MAX; for that, use graphic_weighted_random_char_inclusive_range.

Let $g$ be the number of graphic chars in $[a, b)$. Then we have

$$ P(x) = \begin{cases} \frac{p}{g} & a \leq x < b \ \text{and} \ x \ \text{is graphic} \\ \frac{1-p}{b-a-g} & a \leq x < b \ \text{and} \ x \ \text{is not graphic} \\ 0 & \text{otherwise} \end{cases} $$

To recover the uniform distribution, use $p = g/(b-a)$.

The output length is infinite.

Expected complexity per iteration

Constant time and additional memory.

Panics

Panics if p_denominator is zero or p_denominator > p_denominator, if $a \geq b$, if $[a, b)$ contains no graphic chars, or if $[a, b)$ contains only graphic chars.

Examples

use malachite_base::chars::random::graphic_weighted_random_char_range;
use malachite_base::random::EXAMPLE_SEED;

assert_eq!(
    graphic_weighted_random_char_range(EXAMPLE_SEED, '\u{100}', '\u{400}', 10, 11)
        .take(30)
        .collect::<String>()
        .as_str(),
    "ǘɂŜȢΙƘƣʅΰǟ˳ˊȇ\u{31b}ʰɥΈ\u{324}\u{35a}Ϟ\u{367}\u{337}ƃ\u{342}ʌμƢϳϪǰ"
)