diskann-vector 0.50.1

DiskANN is a fast approximate nearest neighbor search library for high dimensional data
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
141
142

/*
 * Copyright (c) Microsoft Corporation.
 * Licensed under the MIT license.
 */
#![warn(missing_debug_implementations, missing_docs)]
use std::str::FromStr;

#[repr(C)]
/// Distance metric
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub enum Metric {
    /// Cosine similarity
    Cosine,
    /// Inner product
    InnerProduct,
    /// Squared Euclidean (L2-Squared)
    L2,
    /// Normalized Cosine Similarity
    CosineNormalized,
}

impl Metric {
    /// Returns the string representation of the metric.
    pub const fn as_str(self) -> &'static str {
        match self {
            Metric::Cosine => "cosine",
            Metric::InnerProduct => "innerproduct",
            Metric::L2 => "l2",
            Metric::CosineNormalized => "cosinenormalized",
        }
    }
}

impl From<Metric> for i32 {
    fn from(metric: Metric) -> Self {
        metric as i32
    }
}

impl TryFrom<i32> for Metric {
    type Error = TryFromMetricError;

    fn try_from(value: i32) -> Result<Self, Self::Error> {
        match value {
            x if x == Metric::Cosine.into() => Ok(Metric::Cosine),
            x if x == Metric::InnerProduct.into() => Ok(Metric::InnerProduct),
            x if x == Metric::L2.into() => Ok(Metric::L2),
            x if x == Metric::CosineNormalized.into() => Ok(Metric::CosineNormalized),
            _ => Err(TryFromMetricError(value)),
        }
    }
}

/// Error returned when an `i32` value does not correspond to a valid [`Metric`] variant.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct TryFromMetricError(pub i32);

impl std::fmt::Display for TryFromMetricError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "invalid Metric discriminant: {}", self.0)
    }
}

impl std::error::Error for TryFromMetricError {}

impl std::fmt::Display for Metric {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(self.as_str())
    }
}

#[derive(Debug)]
pub enum ParseMetricError {
    InvalidFormat(String),
}

impl std::fmt::Display for ParseMetricError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::InvalidFormat(str) => write!(f, "Invalid format for Metric: {}", str),
        }
    }
}

impl std::error::Error for ParseMetricError {}

impl FromStr for Metric {
    type Err = ParseMetricError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            x if x == Metric::L2.as_str() => Ok(Metric::L2),
            x if x == Metric::Cosine.as_str() => Ok(Metric::Cosine),
            x if x == Metric::InnerProduct.as_str() => Ok(Metric::InnerProduct),
            x if x == Metric::CosineNormalized.as_str() => Ok(Metric::CosineNormalized),
            _ => Err(ParseMetricError::InvalidFormat(String::from(s))),
        }
    }
}

#[cfg(test)]
mod tests {
    use std::str::FromStr;

    use super::{Metric, ParseMetricError, TryFromMetricError};

    #[test]
    fn test_metric_from_str() {
        assert_eq!(Metric::from_str("cosine").unwrap(), Metric::Cosine);
        assert_eq!(Metric::from_str("l2").unwrap(), Metric::L2);
        assert_eq!(
            Metric::from_str("innerproduct").unwrap(),
            Metric::InnerProduct
        );
        assert_eq!(
            Metric::from_str("cosinenormalized").unwrap(),
            Metric::CosineNormalized
        );
        assert_eq!(
            Metric::from_str("invalid").unwrap_err().to_string(),
            ParseMetricError::InvalidFormat(String::from("invalid")).to_string()
        );
    }

    #[test]
    fn test_metric_to_i32() {
        assert_eq!(i32::from(Metric::Cosine), 0);
        assert_eq!(i32::from(Metric::InnerProduct), 1);
        assert_eq!(i32::from(Metric::L2), 2);
        assert_eq!(i32::from(Metric::CosineNormalized), 3);
    }

    #[test]
    fn test_metric_try_from_i32() {
        assert_eq!(Metric::try_from(0), Ok(Metric::Cosine));
        assert_eq!(Metric::try_from(1), Ok(Metric::InnerProduct));
        assert_eq!(Metric::try_from(2), Ok(Metric::L2));
        assert_eq!(Metric::try_from(3), Ok(Metric::CosineNormalized));
        assert_eq!(Metric::try_from(-1), Err(TryFromMetricError(-1)));
        assert_eq!(Metric::try_from(4), Err(TryFromMetricError(4)));
    }
}