malachite_nz/integer_polynomial/arithmetic/
shl.rs

1// Copyright © 2026 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 crate::integer_polynomial::IntegerPolynomial;
11use core::ops::{Shl, ShlAssign};
12
13// Shifts every coefficient left by `bits`. A nonzero coefficient stays nonzero, and keeps its sign,
14// so the result is normalized.
15//
16// This is equivalent to `fmpz_poly_scalar_mul_2exp` from `fmpz_poly/scalar.c`, FLINT 3.6.0.
17fn shl_ref<T: Copy>(p: &IntegerPolynomial, bits: T) -> IntegerPolynomial
18where
19    for<'a> &'a Integer: Shl<T, Output = Integer>,
20{
21    IntegerPolynomial {
22        coefficients: p.coefficients.iter().map(|c| c << bits).collect(),
23    }
24}
25
26// Shifts every coefficient left by `bits`, in place.
27//
28// This is equivalent to `fmpz_poly_scalar_mul_2exp` from `fmpz_poly/scalar.c`, FLINT 3.6.0.
29fn shl_assign<T: Copy>(p: &mut IntegerPolynomial, bits: T)
30where
31    Integer: ShlAssign<T>,
32{
33    for c in &mut p.coefficients {
34        *c <<= bits;
35    }
36}
37
38macro_rules! impl_integer_polynomial_shl_unsigned {
39    ($t:ident) => {
40        impl Shl<$t> for IntegerPolynomial {
41            type Output = IntegerPolynomial;
42
43            /// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), taking it by
44            /// value. Every coefficient is shifted.
45            ///
46            /// $f(p, k) = 2^kp$.
47            ///
48            /// # Worst-case complexity
49            /// $T(n, m, k) = O(n + km)$
50            ///
51            /// $M(n, m, k) = O(n + km)$
52            ///
53            /// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
54            /// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
55            ///
56            /// # Examples
57            /// See [here](super::shl#shl).
58            #[inline]
59            fn shl(mut self, bits: $t) -> IntegerPolynomial {
60                self <<= bits;
61                self
62            }
63        }
64
65        impl Shl<$t> for &IntegerPolynomial {
66            type Output = IntegerPolynomial;
67
68            /// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), taking it by
69            /// reference. Every coefficient is shifted.
70            ///
71            /// $f(p, k) = 2^kp$.
72            ///
73            /// # Worst-case complexity
74            /// $T(n, m, k) = O(n + km)$
75            ///
76            /// $M(n, m, k) = O(n + km)$
77            ///
78            /// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
79            /// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
80            ///
81            /// # Examples
82            /// See [here](super::shl#shl).
83            #[inline]
84            fn shl(self, bits: $t) -> IntegerPolynomial {
85                shl_ref(self, bits)
86            }
87        }
88
89        impl ShlAssign<$t> for IntegerPolynomial {
90            /// Left-shifts an [`IntegerPolynomial`] (multiplies it by a power of 2), in place.
91            /// Every coefficient is shifted.
92            ///
93            /// $p \gets 2^kp$.
94            ///
95            /// # Worst-case complexity
96            /// $T(n, m, k) = O(n + km)$
97            ///
98            /// $M(n, m, k) = O(n + km)$
99            ///
100            /// where $T$ is time, $M$ is additional memory, $n$ is the total number of bits of the
101            /// coefficients, $m$ is `bits`, and $k$ is `self.len()`.
102            ///
103            /// # Examples
104            /// See [here](super::shl#shl_assign).
105            #[inline]
106            fn shl_assign(&mut self, bits: $t) {
107                shl_assign(self, bits);
108            }
109        }
110    };
111}
112apply_to_unsigneds!(impl_integer_polynomial_shl_unsigned);
malachite_nz/integer_polynomial/arithmetic/shl.rs

malachite_nz/integer_polynomial/arithmetic/
shl.rs
