malachite_float/comparison/
eq_abs_integer.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::Float;
10use crate::InnerFloat::{Finite, Zero};
11use core::cmp::Ordering::*;
12use malachite_base::num::comparison::traits::EqAbs;
13use malachite_base::num::logic::traits::SignificantBits;
14use malachite_nz::integer::Integer;
15
16impl EqAbs<Integer> for Float {
17    /// Determines whether the absolute value of a [`Float`] is equal to the absolute value of an
18    /// [`Integer`].
19    ///
20    /// $\infty$, $-\infty$, and NaN are not equal to any [`Integer`]. Both the [`Float`] zero and
21    /// the [`Float`] negative zero are equal to the [`Integer`] zero.
22    ///
23    /// # Worst-case complexity
24    /// $T(n) = O(n)$
25    ///
26    /// $M(n) = O(1)$
27    ///
28    /// where $T$ is time, $M$ is additional memory, and $n$ is `min(self.significant_bits(),
29    /// other.significant_bits())`.
30    ///
31    /// # Examples
32    /// ```
33    /// use malachite_base::num::basic::traits::{One, OneHalf};
34    /// use malachite_base::num::comparison::traits::EqAbs;
35    /// use malachite_float::Float;
36    /// use malachite_nz::integer::Integer;
37    ///
38    /// assert!(Float::from(123).eq_abs(&Integer::from(123)));
39    /// assert!(Float::from(-123).eq_abs(&Integer::from(-123)));
40    /// assert!(Float::ONE_HALF.ne_abs(&Integer::ONE));
41    /// ```
42    fn eq_abs(&self, other: &Integer) -> bool {
43        match self {
44            float_either_zero!() => *other == 0u32,
45            Self(Finite {
46                exponent,
47                significand,
48                ..
49            }) => {
50                *other != 0u32
51                    && *exponent >= 0
52                    && other.significant_bits() == u64::from(exponent.unsigned_abs())
53                    && significand.cmp_normalized(other.unsigned_abs_ref()) == Equal
54            }
55            _ => false,
56        }
57    }
58}
59
60impl EqAbs<Float> for Integer {
61    /// Determines whether the absolute value of an [`Integer`] is equal to the absolute value of a
62    /// [`Float`].
63    ///
64    /// No [`Integer`] is equal to $\infty$, $-\infty$, or NaN. The [`Integer`] zero is equal to
65    /// both the [`Float`] zero and the [`Float`] negative zero.
66    ///
67    /// # Worst-case complexity
68    /// $T(n) = O(n)$
69    ///
70    /// $M(n) = O(1)$
71    ///
72    /// where $T$ is time, $M$ is additional memory, and $n$ is `min(self.significant_bits(),
73    /// other.significant_bits())`.
74    ///
75    /// # Examples
76    /// ```
77    /// use malachite_base::num::basic::traits::{One, OneHalf};
78    /// use malachite_base::num::comparison::traits::EqAbs;
79    /// use malachite_float::Float;
80    /// use malachite_nz::integer::Integer;
81    ///
82    /// assert!(Integer::from(123).eq_abs(&Float::from(123)));
83    /// assert!(Integer::from(-123).eq_abs(&Float::from(-123)));
84    /// assert!(Integer::ONE.ne_abs(&Float::ONE_HALF));
85    /// ```
86    #[inline]
87    fn eq_abs(&self, other: &Float) -> bool {
88        other.eq_abs(self)
89    }
90}
malachite_float/comparison/eq_abs_integer.rs

malachite_float/comparison/
eq_abs_integer.rs
