std_cmp/
std_cmp.rs

1use std::f64::consts::PI;
2
3const STEP: f64 = 0.001;
4
5fn main() {
6    println!(
7        "{:<7}|{:>12}|{:>11}|{:>15}",
8        "Func", "Total Tests", "Diff Count", "Max Diff"
9    );
10    let tests = [
11        CompareArgs {
12            name: "acos".to_string(),
13            start: -1.0,
14            stop: 1.0,
15            step: STEP,
16            std_fn: |x| x.acos(),
17            const_fn: |x: f64| trig_const::acos(x),
18        },
19        CompareArgs {
20            name: "acosh".to_string(),
21            start: 1.0,
22            stop: 100.0,
23            step: STEP,
24            std_fn: |x| x.acosh(),
25            const_fn: |x: f64| trig_const::acosh(x),
26        },
27        CompareArgs {
28            name: "asin".to_string(),
29            start: -1.0,
30            stop: 1.0,
31            step: STEP,
32            std_fn: |x| x.asin(),
33            const_fn: |x: f64| trig_const::asin(x),
34        },
35        CompareArgs {
36            name: "asinh".to_string(),
37            start: 1.0,
38            stop: 100.0,
39            step: STEP,
40            std_fn: |x| x.asinh(),
41            const_fn: |x: f64| trig_const::asinh(x),
42        },
43        CompareArgs {
44            name: "atan".to_string(),
45            start: -8.0 * PI,
46            stop: 8.0 * PI,
47            step: STEP,
48            std_fn: |x| x.atan(),
49            const_fn: |x: f64| trig_const::atan(x),
50        },
51        CompareArgs {
52            name: "atanh".to_string(),
53            start: -1.0 + STEP,
54            stop: 1.0 - STEP,
55            step: STEP,
56            std_fn: |x| x.atanh(),
57            const_fn: |x| trig_const::atanh(x),
58        },
59        CompareArgs {
60            name: "cos".to_string(),
61            start: -8.0 * PI,
62            stop: 8.0 * PI,
63            step: STEP,
64            std_fn: |x| x.cos(),
65            const_fn: |x: f64| trig_const::cos(x),
66        },
67        CompareArgs {
68            name: "cosh".to_string(),
69            start: -4.0 * PI,
70            stop: 4.0 * PI,
71            step: STEP,
72            std_fn: |x| x.cosh(),
73            const_fn: |x| trig_const::cosh(x),
74        },
75        CompareArgs {
76            name: "ln".to_string(),
77            start: 0.001,
78            stop: 100.0,
79            step: STEP,
80            std_fn: |x| x.ln(),
81            const_fn: |x: f64| trig_const::ln(x),
82        },
83        CompareArgs {
84            name: "exp".to_string(),
85            start: -10.0,
86            stop: 10.0,
87            step: STEP,
88            std_fn: |x| x.exp(),
89            const_fn: |x: f64| trig_const::exp(x),
90        },
91        CompareArgs {
92            name: "fabs".to_string(),
93            start: -10.0,
94            stop: 10.0,
95            step: STEP,
96            std_fn: |x| x.abs(),
97            const_fn: |x: f64| trig_const::fabs(x),
98        },
99        CompareArgs {
100            name: "floor".to_string(),
101            start: -10.0,
102            stop: 10.0,
103            step: STEP,
104            std_fn: |x| x.floor(),
105            const_fn: |x: f64| trig_const::floor(x),
106        },
107        CompareArgs {
108            name: "sin".to_string(),
109            start: -8.0 * PI,
110            stop: 8.0 * PI,
111            step: STEP,
112            std_fn: |x| x.sin(),
113            const_fn: |x: f64| trig_const::sin(x),
114        },
115        CompareArgs {
116            name: "sinh".to_string(),
117            start: -4.0 * PI,
118            stop: 4.0 * PI,
119            step: STEP,
120            std_fn: |x| x.sinh(),
121            const_fn: |x| trig_const::sinh(x),
122        },
123        CompareArgs {
124            name: "sqrt".to_string(),
125            start: 0.0,
126            stop: 10.0,
127            step: STEP,
128            std_fn: |x| x.sqrt(),
129            const_fn: |x: f64| trig_const::sqrt(x),
130        },
131        CompareArgs {
132            name: "tan".to_string(),
133            start: -8.0 * PI,
134            stop: 8.0 * PI,
135            step: STEP,
136            std_fn: |x| x.tan(),
137            const_fn: |x: f64| trig_const::tan(x),
138        },
139    ];
140
141    for test in tests {
142        let diff = compare_functions(&test);
143        println!(
144            "{:<7}|{:>12}|{:>11}|{:>15.5e}",
145            test.name, diff.total_tests, diff.diff_tests, diff.max_diff
146        );
147    }
148}
149
150fn compare_functions(c: &CompareArgs) -> DiffCounter {
151    let mut const_metric = DiffCounter::default();
152
153    for x in float_loop(c.start, c.stop, c.step) {
154        let real = (c.std_fn)(x);
155        let const_result = (c.const_fn)(x);
156
157        const_metric.add_metric(real, const_result);
158    }
159
160    const_metric
161}
162
163#[derive(Debug, Default)]
164struct DiffCounter {
165    total_tests: usize,
166    diff_tests: usize,
167    max_diff: f64,
168}
169
170impl DiffCounter {
171    fn add_metric(&mut self, real: f64, actual: f64) {
172        self.total_tests += 1;
173        let diff = (real - actual).abs();
174        if diff != 0.0 {
175            self.diff_tests += 1;
176            self.max_diff = f64::max(self.max_diff, diff);
177        }
178    }
179}
180
181fn float_loop(start: f64, stop: f64, step: f64) -> impl Iterator<Item = f64> {
182    core::iter::successors(Some(start), move |prev| {
183        let next = prev + step;
184        (next < stop).then_some(next)
185    })
186}
187
188struct CompareArgs {
189    name: String,
190    start: f64,
191    stop: f64,
192    step: f64,
193    std_fn: fn(f64) -> f64,
194    const_fn: fn(f64) -> f64,
195}
std_cmp/std_cmp.rs

std_cmp/
std_cmp.rs
