Enum RoundingMode 

pub enum RoundingMode {
    HalfToEven,
    HalfAwayFromZero,
    HalfTowardZero,
    Trunc,
    Floor,
    Ceiling,
}

Selector for the rounding rule applied when a scale-narrowing operation discards fractional digits.

See the module-level documentation for when each rule applies.

Precision

N/A: this is a tag; no arithmetic is performed by constructing or comparing variants.

Variants

HalfToEven

Round to nearest; on ties, round to the even neighbour. IEEE-754 roundTiesToEven; also called banker’s rounding. Unbiased — repeated rounding does not drift sums. Crate default.

Examples (truncate to integer): 0.5 -> 0, 1.5 -> 2, 2.5 -> 2, -0.5 -> 0, -1.5 -> -2.

HalfAwayFromZero

Round to nearest; on ties, round away from zero. Commercial rounding. Mildly biased in magnitude.

Examples: 0.5 -> 1, 1.5 -> 2, -0.5 -> -1, -1.5 -> -2.

HalfTowardZero

Round to nearest; on ties, round toward zero. Mildly biased toward zero. Rare in practice; included for completeness.

Examples: 0.5 -> 0, 1.5 -> 1, -0.5 -> 0, -1.5 -> -1.

Trunc

Truncate toward zero. Discards the fractional part. Cheapest in integer arithmetic; matches Rust’s as cast for integer narrowing.

Examples: 0.7 -> 0, -0.7 -> 0, 1.9 -> 1, -1.9 -> -1.

Floor

Round toward negative infinity (floor).

Examples: 0.7 -> 0, -0.7 -> -1, 1.9 -> 1, -1.9 -> -2.

Ceiling

Round toward positive infinity (ceiling).

Examples: 0.7 -> 1, -0.7 -> 0, 1.9 -> 2, -1.9 -> -1.

Trait Implementations

impl Clone for RoundingMode

fn clone(&self) -> RoundingMode

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RoundingMode

impl Debug for RoundingMode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for RoundingMode

impl Hash for RoundingMode

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for RoundingMode

fn eq(&self, other: &RoundingMode) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for RoundingMode