cdflib 0.4.1

Pure-Rust port of CDFLIB: cumulative distribution functions (CDF) associated with common probability distributions
Documentation 
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

#![cfg(not(miri))]

//! Sanity tests for the crate scaffolding: error type, traits, and the
//! shared test helpers in `tests/common/mod.rs`.

mod common;

use cdflib::{ContinuousCdf, DiscreteCdf, SearchError};
use common::{assert_close, assert_close_eps, read_csv};
use std::f64::consts::PI;

// --- assert_close ---------------------------------------------------------

#[test]
fn assert_close_passes_when_within_default_tol() {
    assert_close(1.0 + 1e-15, 1.0);
    assert_close(-PI, -PI);
}

#[test]
fn assert_close_handles_boundary_values() {
    // At expected = 0.0 only the absolute tolerance applies.
    assert_close_eps(1e-310, 0.0, 1e-14, 1e-300);
    // At expected = 1.0 likewise.
    assert_close_eps(1.0, 1.0, 1e-14, 1e-300);
}

#[test]
#[should_panic(expected = "rel diff")]
fn assert_close_fails_outside_tol() {
    assert_close_eps(1.0, 2.0, 1e-14, 1e-300);
}

#[test]
#[should_panic(expected = "NaN mismatch")]
fn assert_close_fails_on_nan_mismatch() {
    assert_close_eps(f64::NAN, 0.0, 1e-14, 1e-300);
}

#[test]
fn assert_close_accepts_both_nan() {
    assert_close_eps(f64::NAN, f64::NAN, 1e-14, 1e-300);
}

#[test]
#[should_panic(expected = "infinity mismatch")]
fn assert_close_fails_on_infinity_mismatch() {
    assert_close_eps(f64::INFINITY, 1e308, 1e-14, 1e-300);
}

// --- read_csv -------------------------------------------------------------

#[test]
#[cfg_attr(miri, ignore)] // miri disables filesystem access by default
fn read_csv_parses_a_simple_table() {
    // Write a temporary fixture then read it back.
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    let path = std::path::Path::new(manifest_dir).join("tests/data/_self_test.csv");
    std::fs::create_dir_all(path.parent().unwrap()).unwrap();
    std::fs::write(
        &path,
        "# header line\n1.0, 2.0, 3.0\n# comment in the middle\n4.5,5.5,6.5\n\n",
    )
    .unwrap();

    let rows = read_csv("tests/data/_self_test.csv");
    assert_eq!(rows, vec![vec![1.0, 2.0, 3.0], vec![4.5, 5.5, 6.5]]);

    let _ = std::fs::remove_file(&path);
}

// --- error / trait shape sanity ------------------------------------------

#[test]
fn search_error_displays_useful_messages() {
    let e = SearchError::AnswerBelowLowerBound { bound: -1.0 };
    assert!(e.to_string().contains("-1"), "got: {e}");
    let e = SearchError::AnswerAboveUpperBound { bound: 1.0 };
    assert!(e.to_string().contains('1'), "got: {e}");
}

// A tiny stub distribution to prove the trait shape compiles.

#[derive(Debug)]
struct StubContinuous;

impl ContinuousCdf for StubContinuous {
    type Error = SearchError;
    fn cdf(&self, x: f64) -> f64 {
        // Uniform on [0..1].
        x.clamp(0.0, 1.0)
    }
    fn inverse_cdf(&self, p: f64) -> Result<f64, SearchError> {
        Ok(p.clamp(0.0, 1.0))
    }

    fn ccdf(&self, x: f64) -> f64 {
        1.0 - self.cdf(x)
    }
}

#[test]
fn continuous_cdf_trait_shape_compiles() {
    let d = StubContinuous;
    assert_close(d.ccdf(0.3), 0.7);
    assert_close(d.inverse_cdf(0.3).unwrap(), 0.3);
}

#[derive(Debug)]
struct StubDiscrete;

impl DiscreteCdf for StubDiscrete {
    type Error = SearchError;
    fn cdf(&self, x: u64) -> f64 {
        if x >= 1 {
            1.0
        } else {
            0.0
        }
    }
    fn ccdf(&self, x: u64) -> f64 {
        if x >= 1 {
            0.0
        } else {
            1.0
        }
    }
    fn inverse_cdf(&self, p: f64) -> Result<u64, SearchError> {
        Ok(if p > 0.0 { 1 } else { 0 })
    }
}

#[test]
fn discrete_cdf_trait_shape_compiles() {
    let d = StubDiscrete;
    assert_close(d.ccdf(0), 1.0);
    assert_close(d.ccdf(1), 0.0);
    assert_eq!(d.inverse_cdf(1.0).unwrap(), 1);
    assert_eq!(d.inverse_cdf(0.0).unwrap(), 0);
}