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Round

dashu_float::round

Trait Round 

Source 
pub trait Round: Copy {
    type Reverse: Round;

    const IS_ROUND_TOWARD_NEGATIVE: bool;

    // Required method
    fn round_low_part<F: FnOnce() -> Ordering>(
        integer: &IBig,
        low_sign: Sign,
        low_half_test: F,
    ) -> Rounding;

    // Provided methods
    fn round_fract<const B: Word>(
        integer: &IBig,
        fract: IBig,
        precision: usize,
    ) -> Rounding { ... }
    fn round_ratio(integer: &IBig, num: IBig, den: &IBig) -> Rounding { ... }
}
Expand description

A trait describing the rounding strategy

Required Associated Constants§

Source

const IS_ROUND_TOWARD_NEGATIVE: bool

Whether this mode rounds toward negative infinity (IEEE roundTowardNegative). Used to determine the sign of a zero produced by exact cancellation: per IEEE 754, x + (-x) yields -0 only under roundTowardNegative, +0 otherwise.

Required Associated Types§

Source

type Reverse: Round

The rounding operation that rounds to an opposite direction

Required Methods§

Source

fn round_low_part<F: FnOnce() -> Ordering>( integer: &IBig, low_sign: Sign, low_half_test: F, ) -> Rounding

Calculate the rounding of the number (integer + rem), assuming rem != 0 and |rem| < 1. low_half_test should tell |rem|.cmp(0.5)

Implementations must decide from the sign of integer alone (plus, when low_half_test returns Equal, its parity via bit(0)) — some callers (e.g. the remainder kernel) pass a small stand-in carrying only those bits of a much larger integer.

Provided Methods§

Source

fn round_fract<const B: Word>( integer: &IBig, fract: IBig, precision: usize, ) -> Rounding

Calculate the rounding of the number (integer + fract / X^precision), assuming |fract| / X^precision < 1. Return the adjustment.

Source

fn round_ratio(integer: &IBig, num: IBig, den: &IBig) -> Rounding

Calculate the rounding of the number (integer + numerator / denominator), assuming |numerator / denominator| < 1. Return the adjustment.

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§