1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
mod iter;
use crate::number::Number;
use iter::Iter;
use std::fmt;
use std::ops::{Add, Mul, Sub};
#[derive(PartialEq, Debug, Clone)]
pub struct Poly {
data: Vec<Number>,
degree: usize,
}
impl Poly {
pub fn new(data: Vec<Number>) -> Poly {
let mut i = data.len() - 1;
while data[i] == 0.0 && i > 0 {
i -= 1;
}
Poly { data, degree: i }
}
fn mono(degree: usize, coefficient: Number) -> Poly {
if coefficient != 0.0 {
let mut p = vec![0.0; degree + 1];
p[degree] = coefficient;
Poly::new(p)
} else {
Poly::new(vec![0.0])
}
}
pub fn degree(&self) -> usize {
self.degree
}
fn iter(&self) -> Iter {
Iter::new(self.data.clone(), self.degree())
}
fn is_zero(&self) -> bool {
for i in 0..self.data.len() {
if self.data[i] != 0.0 {
return false;
}
}
true
}
}
impl Add for &Poly {
type Output = Poly;
fn add(self, other: Self) -> Poly {
Poly::new(self.iter().zip(other.iter()).map(|(x, y)| x + y).collect())
}
}
impl Sub for &Poly {
type Output = Poly;
fn sub(self, other: Self) -> Poly {
Poly::new(self.iter().zip(other.iter()).map(|(x, y)| x - y).collect())
}
}
impl Mul for &Poly {
type Output = Poly;
fn mul(self, other: Self) -> Poly {
let mut r = Vec::new();
for i in 0..other.degree() + 1 {
let mut prefix = vec![0.0; i];
let mut suffix: Vec<Number> = self
.iter()
.take(self.degree() + 1)
.map(|x| x * other.data[i])
.collect();
prefix.append(&mut suffix);
r.push(Poly::new(prefix));
}
r.iter().fold(Poly::new(vec![0.0]), |acc, x| &acc + x)
}
}
impl fmt::Display for &Poly {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut s = String::new();
for i in 0..self.data.len() {
s.push_str(&self.data[i].clone().to_string());
if i < self.data.len() - 1 {
s.push_str(", ");
}
}
write!(f, "{}", s)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn mul_test() {
let a = Poly::new(vec![1.0, 2.0, 3.0]);
let b = Poly::new(vec![1.0, 2.0]);
assert_eq!(&a * &b, Poly::new(vec![1.0, 4.0, 7.0, 6.0]));
}
#[test]
fn add_test() {
let a = Poly::new(vec![1.0]);
let b = Poly::new(vec![0.0, 0.0, 0.0, 1.0]);
assert_eq!(&a + &b, Poly::new(vec![1.0, 0.0, 0.0, 1.0]));
}
#[test]
fn sub_test() {
let a = Poly::new(vec![1.0, 2.0, 3.0]);
let b = Poly::new(vec![1.0, 1.0, 1.0]);
assert_eq!(&a - &b, Poly::new(vec![0.0, 1.0, 2.0]));
}
#[test]
fn poly_is_zero() {
let p = Poly::new(vec![0.0; 5]);
assert_eq!(p.is_zero(), true);
}
#[test]
fn poly_is_not_zero() {
let p = Poly::mono(5, 8.0);
assert_eq!(p.is_zero(), false);
}
#[test]
fn degree_is_five() {
let p = Poly::mono(5, 2.0);
assert_eq!(p.degree(), 5);
}
#[test]
fn degree_is_zero() {
let p = Poly::new(vec![0.0; 6]);
assert_eq!(p.degree(), 0);
}
}
|
