malachite_nz/integer/conversion/string/
to_sci.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::integer::Integer;
10use core::fmt::{Formatter, Write};
11use malachite_base::num::conversion::string::options::ToSciOptions;
12use malachite_base::num::conversion::traits::ToSci;
13
14impl ToSci for Integer {
15    /// Determines whether an [`Integer`] can be converted to a string using
16    /// [`to_sci`](`Self::to_sci`) and a particular set of options.
17    ///
18    /// # Worst-case complexity
19    /// $T(n) = O(n \log n \log\log n)$
20    ///
21    /// $M(n) = O(n \log n)$
22    ///
23    /// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
24    ///
25    /// # Examples
26    /// ```
27    /// use malachite_base::num::conversion::string::options::ToSciOptions;
28    /// use malachite_base::num::conversion::traits::ToSci;
29    /// use malachite_base::rounding_modes::RoundingMode::*;
30    /// use malachite_nz::integer::Integer;
31    ///
32    /// let mut options = ToSciOptions::default();
33    /// assert!(Integer::from(123).fmt_sci_valid(options));
34    /// assert!(Integer::from(u128::MAX).fmt_sci_valid(options));
35    /// // u128::MAX has more than 16 significant digits
36    /// options.set_rounding_mode(Exact);
37    /// assert!(!Integer::from(u128::MAX).fmt_sci_valid(options));
38    /// options.set_precision(50);
39    /// assert!(Integer::from(u128::MAX).fmt_sci_valid(options));
40    /// ```
41    #[inline]
42    fn fmt_sci_valid(&self, options: ToSciOptions) -> bool {
43        self.unsigned_abs_ref().fmt_sci_valid(options)
44    }
45
46    /// Converts an [`Integer`] to a string using a specified base, possibly formatting the number
47    /// using scientific notation.
48    ///
49    /// See [`ToSciOptions`] for details on the available options. Note that setting
50    /// `neg_exp_threshold` has no effect, since there is never a need to use negative exponents
51    /// when representing an [`Integer`].
52    ///
53    /// # Worst-case complexity
54    /// $T(n) = O(n (\log n)^2 \log\log n)$
55    ///
56    /// $M(n) = O(n \log n)$
57    ///
58    /// where $T$ is time, $M$ is additional memory, and $n$ is `self.significant_bits()`.
59    ///
60    /// # Panics
61    /// Panics if `options.rounding_mode` is `Exact`, but the size options are such that the input
62    /// must be rounded.
63    ///
64    /// # Examples
65    /// ```
66    /// use malachite_base::num::conversion::string::options::ToSciOptions;
67    /// use malachite_base::num::conversion::traits::ToSci;
68    /// use malachite_base::rounding_modes::RoundingMode::*;
69    /// use malachite_nz::integer::Integer;
70    ///
71    /// assert_eq!(
72    ///     Integer::from(u128::MAX).to_sci().to_string(),
73    ///     "3.402823669209385e38"
74    /// );
75    /// assert_eq!(
76    ///     Integer::from(i128::MIN).to_sci().to_string(),
77    ///     "-1.701411834604692e38"
78    /// );
79    ///
80    /// let n = Integer::from(123456u32);
81    /// let mut options = ToSciOptions::default();
82    /// assert_eq!(n.to_sci_with_options(options).to_string(), "123456");
83    ///
84    /// options.set_precision(3);
85    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.23e5");
86    ///
87    /// options.set_rounding_mode(Ceiling);
88    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.24e5");
89    ///
90    /// options.set_e_uppercase();
91    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.24E5");
92    ///
93    /// options.set_force_exponent_plus_sign(true);
94    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.24E+5");
95    ///
96    /// options = ToSciOptions::default();
97    /// options.set_base(36);
98    /// assert_eq!(n.to_sci_with_options(options).to_string(), "2n9c");
99    ///
100    /// options.set_uppercase();
101    /// assert_eq!(n.to_sci_with_options(options).to_string(), "2N9C");
102    ///
103    /// options.set_base(2);
104    /// options.set_precision(10);
105    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.1110001e16");
106    ///
107    /// options.set_include_trailing_zeros(true);
108    /// assert_eq!(n.to_sci_with_options(options).to_string(), "1.111000100e16");
109    /// ```
110    fn fmt_sci(&self, f: &mut Formatter, mut options: ToSciOptions) -> core::fmt::Result {
111        let abs = self.unsigned_abs_ref();
112        if *self >= 0u32 {
113            abs.fmt_sci(f, options)
114        } else {
115            options.set_rounding_mode(-options.get_rounding_mode());
116            f.write_char('-')?;
117            abs.fmt_sci(f, options)
118        }
119    }
120}
malachite_nz/integer/conversion/string/to_sci.rs

malachite_nz/integer/conversion/string/
to_sci.rs
