malachite_q/arithmetic/
abs.rs

1// Copyright © 2025 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::Rational;
10use malachite_base::num::arithmetic::traits::{Abs, AbsAssign};
11
12impl Abs for Rational {
13    type Output = Self;
14
15    /// Takes the absolute value of a [`Rational`], taking the [`Rational`] by value.
16    ///
17    /// $$
18    /// f(x) = |x|.
19    /// $$
20    ///
21    /// # Worst-case complexity
22    /// Constant time and additional memory.
23    ///
24    /// # Examples
25    /// ```
26    /// use malachite_base::num::arithmetic::traits::Abs;
27    /// use malachite_base::num::basic::traits::Zero;
28    /// use malachite_q::Rational;
29    ///
30    /// assert_eq!(Rational::ZERO.abs(), 0);
31    /// assert_eq!(Rational::from_signeds(22, 7).abs().to_string(), "22/7");
32    /// assert_eq!(Rational::from_signeds(-22, 7).abs().to_string(), "22/7");
33    /// ```
34    fn abs(mut self) -> Self {
35        self.sign = true;
36        self
37    }
38}
39
40impl Abs for &Rational {
41    type Output = Rational;
42
43    /// Takes the absolute value of a [`Rational`], taking the [`Rational`] by reference.
44    ///
45    /// $$
46    /// f(x) = |x|.
47    /// $$
48    ///
49    /// # Worst-case complexity
50    /// $T(n) = O(n)$
51    ///
52    /// $M(n) = O(n)$
53    ///
54    /// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
55    ///
56    /// # Examples
57    /// ```
58    /// use malachite_base::num::arithmetic::traits::Abs;
59    /// use malachite_base::num::basic::traits::Zero;
60    /// use malachite_q::Rational;
61    ///
62    /// assert_eq!((&Rational::ZERO).abs(), 0);
63    /// assert_eq!((&Rational::from_signeds(22, 7)).abs().to_string(), "22/7");
64    /// assert_eq!((&Rational::from_signeds(-22, 7)).abs().to_string(), "22/7");
65    /// ```
66    fn abs(self) -> Rational {
67        Rational {
68            sign: true,
69            numerator: self.numerator.clone(),
70            denominator: self.denominator.clone(),
71        }
72    }
73}
74
75impl AbsAssign for Rational {
76    /// Replaces a [`Rational`] with its absolute value.
77    ///
78    /// $$
79    /// x \gets |x|.
80    /// $$
81    ///
82    /// # Examples
83    /// ```
84    /// use malachite_base::num::arithmetic::traits::AbsAssign;
85    /// use malachite_base::num::basic::traits::Zero;
86    /// use malachite_q::Rational;
87    ///
88    /// let mut x = Rational::ZERO;
89    /// x.abs_assign();
90    /// assert_eq!(x, 0);
91    ///
92    /// let mut x = Rational::from_signeds(22, 7);
93    /// x.abs_assign();
94    /// assert_eq!(x.to_string(), "22/7");
95    ///
96    /// let mut x = Rational::from_signeds(-22, 7);
97    /// x.abs_assign();
98    /// assert_eq!(x.to_string(), "22/7");
99    /// ```
100    fn abs_assign(&mut self) {
101        self.sign = true;
102    }
103}
malachite_q/arithmetic/abs.rs

malachite_q/arithmetic/
abs.rs
