qfall_math/rational/poly_over_q/
properties.rs

1// Copyright © 2023 Phil Milewski
2//
3// This file is part of qFALL-math.
4//
5// qFALL-math is free software: you can redistribute it and/or modify it under
6// the terms of the Mozilla Public License Version 2.0 as published by the
7// Mozilla Foundation. See <https://mozilla.org/en-US/MPL/2.0/>.
8
9//! This module includes functionality about properties of [`PolyOverQ`] instances.
10
11use flint_sys::fmpq_poly::{fmpq_poly_degree, fmpq_poly_is_one};
12
13use super::PolyOverQ;
14
15impl PolyOverQ {
16    /// Checks if a [`PolyOverQ`] is the constant polynomial with coefficient `1`.
17    ///
18    /// Returns `true` if there is only one coefficient, which is `1`.
19    ///
20    /// # Examples
21    /// ```
22    /// use qfall_math::rational::PolyOverQ;
23    /// use std::str::FromStr;
24    ///
25    /// let value = PolyOverQ::from_str("1  1").unwrap();
26    /// assert!(value.is_one());
27    /// ```
28    pub fn is_one(&self) -> bool {
29        1 == unsafe { fmpq_poly_is_one(&self.poly) }
30    }
31
32    /// Checks if every entry of a [`PolyOverQ`] is `0`.
33    ///
34    /// Returns `true` if [`PolyOverQ`] has no coefficients.
35    ///
36    /// # Examples
37    /// ```
38    /// use qfall_math::rational::PolyOverQ;
39    /// use std::str::FromStr;
40    ///
41    /// let value = PolyOverQ::from_str("0").unwrap();
42    /// assert!(value.is_zero());
43    /// ```
44    pub fn is_zero(&self) -> bool {
45        -1 == unsafe { fmpq_poly_degree(&self.poly) }
46    }
47}
48
49#[cfg(test)]
50mod test_is_one {
51    use super::PolyOverQ;
52    use std::str::FromStr;
53
54    /// Ensure that is_one returns `true` for the one polynomial.
55    #[test]
56    fn one_detection() {
57        let one = PolyOverQ::from_str("1  1").unwrap();
58
59        assert!(one.is_one());
60    }
61
62    /// Ensure that is_one returns `false` for other polynomials.
63    #[test]
64    fn one_rejection() {
65        let small = PolyOverQ::from_str("4  1 0 0 1/123").unwrap();
66        let large = PolyOverQ::from_str(&format!("1  {}", (u128::MAX - 1) / 2 + 2)).unwrap();
67
68        assert!(!small.is_one());
69        assert!(!large.is_one());
70    }
71}
72
73#[cfg(test)]
74mod test_is_zero {
75    use super::PolyOverQ;
76    use std::str::FromStr;
77
78    /// Ensure that is_zero returns `true` for the zero polynomial.
79    #[test]
80    fn zero_detection() {
81        let zero = PolyOverQ::from_str("0").unwrap();
82
83        assert!(zero.is_zero());
84    }
85
86    /// Ensure that is_zero returns `false` for non-zero polynomials.
87    #[test]
88    fn zero_rejection() {
89        let small = PolyOverQ::from_str("4  0 0 0 1/8").unwrap();
90        let large = PolyOverQ::from_str(&format!("1  {}", (u128::MAX - 1) / 2 + 1)).unwrap();
91
92        assert!(!small.is_zero());
93        assert!(!large.is_zero());
94    }
95}
qfall_math/rational/poly_over_q/properties.rs

qfall_math/rational/poly_over_q/
properties.rs
