malachite_q/arithmetic/
power_of_2.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::PowerOf2;
11use malachite_base::num::basic::traits::One;
12use malachite_nz::natural::Natural;
13
14impl PowerOf2<u64> for Rational {
15    /// Raises 2 to an integer power.
16    ///
17    /// $f(k) = 2^k$.
18    ///
19    /// # Worst-case complexity
20    /// $T(n) = O(n)$
21    ///
22    /// $M(n) = O(n)$
23    ///
24    /// where $T$ is time, $M$ is additional memory, and $n$ is `pow`.
25    ///
26    /// # Examples
27    /// ```
28    /// use malachite_base::num::arithmetic::traits::PowerOf2;
29    /// use malachite_q::Rational;
30    ///
31    /// assert_eq!(Rational::power_of_2(0u64), 1);
32    /// assert_eq!(Rational::power_of_2(3u64), 8);
33    /// assert_eq!(
34    ///     Rational::power_of_2(100u64).to_string(),
35    ///     "1267650600228229401496703205376"
36    /// );
37    /// ```
38    fn power_of_2(pow: u64) -> Self {
39        Self::from(Natural::power_of_2(pow))
40    }
41}
42
43impl PowerOf2<i64> for Rational {
44    /// Raises 2 to an integer power.
45    ///
46    /// $f(k) = 2^k$.
47    ///
48    /// # Worst-case complexity
49    /// $T(n) = O(n)$
50    ///
51    /// $M(n) = O(n)$
52    ///
53    /// where $T$ is time, $M$ is additional memory, and $n$ is `pow.abs()`.
54    ///
55    /// # Examples
56    /// ```
57    /// use malachite_base::num::arithmetic::traits::PowerOf2;
58    /// use malachite_q::Rational;
59    ///
60    /// assert_eq!(Rational::power_of_2(0i64), 1);
61    /// assert_eq!(Rational::power_of_2(3i64), 8);
62    /// assert_eq!(
63    ///     Rational::power_of_2(100i64).to_string(),
64    ///     "1267650600228229401496703205376"
65    /// );
66    /// assert_eq!(Rational::power_of_2(-3i64).to_string(), "1/8");
67    /// assert_eq!(
68    ///     Rational::power_of_2(-100i64).to_string(),
69    ///     "1/1267650600228229401496703205376"
70    /// );
71    /// ```
72    fn power_of_2(pow: i64) -> Self {
73        let pow_abs = pow.unsigned_abs();
74        if pow >= 0 {
75            Self::from(Natural::power_of_2(pow_abs))
76        } else {
77            Self {
78                sign: true,
79                numerator: Natural::ONE,
80                denominator: Natural::power_of_2(pow_abs),
81            }
82        }
83    }
84}
malachite_q/arithmetic/power_of_2.rs

malachite_q/arithmetic/
power_of_2.rs
