criterion/stats/univariate/
percentiles.rs

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1use cast::{self, usize};
2use stats::float::Float;
3
4/// A "view" into the percentiles of a sample
5pub struct Percentiles<A>(Box<[A]>)
6where
7    A: Float;
8
9// TODO(rust-lang/rfcs#735) move this `impl` into a private percentiles module
10impl<A> Percentiles<A>
11where
12    A: Float,
13    usize: cast::From<A, Output = Result<usize, cast::Error>>,
14{
15    /// Returns the percentile at `p`%
16    ///
17    /// Safety:
18    ///
19    /// - Make sure that `p` is in the range `[0, 100]`
20    unsafe fn at_unchecked(&self, p: A) -> A {
21        let _100 = A::cast(100);
22        debug_assert!(p >= A::cast(0) && p <= _100);
23        debug_assert!(self.0.len() > 0);
24        let len = self.0.len() - 1;
25
26        if p == _100 {
27            self.0[len]
28        } else {
29            let rank = (p / _100) * A::cast(len);
30            let integer = rank.floor();
31            let fraction = rank - integer;
32            let n = usize(integer).unwrap();
33            let &floor = self.0.get_unchecked(n);
34            let &ceiling = self.0.get_unchecked(n + 1);
35
36            floor + (ceiling - floor) * fraction
37        }
38    }
39
40    /// Returns the percentile at `p`%
41    ///
42    /// # Panics
43    ///
44    /// Panics if `p` is outside the closed `[0, 100]` range
45    pub fn at(&self, p: A) -> A {
46        let _0 = A::cast(0);
47        let _100 = A::cast(100);
48
49        assert!(p >= _0 && p <= _100);
50        assert!(self.0.len() > 0);
51
52        unsafe { self.at_unchecked(p) }
53    }
54
55    /// Returns the interquartile range
56    pub fn iqr(&self) -> A {
57        unsafe {
58            let q1 = self.at_unchecked(A::cast(25));
59            let q3 = self.at_unchecked(A::cast(75));
60
61            q3 - q1
62        }
63    }
64
65    /// Returns the 50th percentile
66    pub fn median(&self) -> A {
67        unsafe { self.at_unchecked(A::cast(50)) }
68    }
69
70    /// Returns the 25th, 50th and 75th percentiles
71    pub fn quartiles(&self) -> (A, A, A) {
72        unsafe {
73            (
74                self.at_unchecked(A::cast(25)),
75                self.at_unchecked(A::cast(50)),
76                self.at_unchecked(A::cast(75)),
77            )
78        }
79    }
80}
criterion/stats/univariate/percentiles.rs

criterion/stats/univariate/
percentiles.rs
