Trait rug::ops::SubFromRound [−][src]
pub trait SubFromRound<Lhs = Self> {
type Round;
type Ordering;
fn sub_from_round(&mut self, lhs: Lhs, round: Self::Round) -> Self::Ordering;
}Expand description
Compound subtraction and assignment to the rhs operand with a specified rounding method.
Examples
use core::cmp::Ordering; use rug::{ float::Round, ops::{SubAssignRound, SubFromRound}, Float, }; struct F(f64); impl SubFromRound<f64> for F { type Round = Round; type Ordering = Ordering; fn sub_from_round(&mut self, lhs: f64, round: Round) -> Ordering { let mut f = Float::with_val(53, lhs); let dir = f.sub_assign_round(self.0, round); self.0 = f.to_f64(); dir } } let mut f = F(5.0); let dir = f.sub_from_round(3.0, Round::Nearest); // 3.0 - 5.0 = -2.0 assert_eq!(f.0, -2.0); assert_eq!(dir, Ordering::Equal);
Associated Types
Required methods
fn sub_from_round(&mut self, lhs: Lhs, round: Self::Round) -> Self::Ordering
fn sub_from_round(&mut self, lhs: Lhs, round: Self::Round) -> Self::Ordering
Performs the subtraction.
Examples
use core::cmp::Ordering; use rug::{float::Round, ops::SubFromRound, Float}; // only four significant bits let mut f = Float::with_val(4, 0.3); let dir = f.sub_from_round(-3, Round::Nearest); // −3.3 rounded up to −3.25 assert_eq!(f, -3.25); assert_eq!(dir, Ordering::Greater);