arrow2 0.6.2

Unofficial implementation of Apache Arrow spec in safe Rust
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

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Utils to make benchmarking easier

use rand::distributions::{Alphanumeric, Distribution, Standard};
use rand::{rngs::StdRng, Rng, SeedableRng};

use crate::types::NaturalDataType;
use crate::{array::*, datatypes::*, types::NativeType};

/// Returns fixed seedable RNG
pub fn seedable_rng() -> StdRng {
    StdRng::seed_from_u64(42)
}

/// Creates an random (but fixed-seeded) array of a given size and null density
pub fn create_primitive_array<T>(
    size: usize,
    data_type: DataType,
    null_density: f32,
) -> PrimitiveArray<T>
where
    T: NativeType + NaturalDataType,
    Standard: Distribution<T>,
{
    let mut rng = seedable_rng();

    (0..size)
        .map(|_| {
            if rng.gen::<f32>() < null_density {
                None
            } else {
                Some(rng.gen())
            }
        })
        .collect::<PrimitiveArray<T>>()
        .to(data_type)
}

/// Creates a new [`PrimitiveArray`] from random values with a pre-set seed.
pub fn create_primitive_array_with_seed<T>(
    size: usize,
    data_type: DataType,
    null_density: f32,
    seed: u64,
) -> PrimitiveArray<T>
where
    T: NativeType + NaturalDataType,
    Standard: Distribution<T>,
{
    let mut rng = StdRng::seed_from_u64(seed);

    (0..size)
        .map(|_| {
            if rng.gen::<f32>() < null_density {
                None
            } else {
                Some(rng.gen())
            }
        })
        .collect::<PrimitiveArray<T>>()
        .to(data_type)
}

/// Creates an random (but fixed-seeded) array of a given size and null density
pub fn create_boolean_array(size: usize, null_density: f32, true_density: f32) -> BooleanArray
where
    Standard: Distribution<bool>,
{
    let mut rng = seedable_rng();
    (0..size)
        .map(|_| {
            if rng.gen::<f32>() < null_density {
                None
            } else {
                let value = rng.gen::<f32>() < true_density;
                Some(value)
            }
        })
        .collect()
}

/// Creates an random (but fixed-seeded) [`Utf8Array`] of a given length, number of characters and null density.
pub fn create_string_array<O: Offset>(
    length: usize,
    size: usize,
    null_density: f32,
    seed: u64,
) -> Utf8Array<O> {
    let mut rng = StdRng::seed_from_u64(seed);

    (0..length)
        .map(|_| {
            if rng.gen::<f32>() < null_density {
                None
            } else {
                let value = (&mut rng)
                    .sample_iter(&Alphanumeric)
                    .take(size)
                    .map(char::from)
                    .collect::<String>();
                Some(value)
            }
        })
        .collect()
}