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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179

use super::{
    batcher::Batcher, BatchStrategy, DataLoader, DataLoaderIterator, MultiThreadDataLoader,
    Progress,
};
use burn_dataset::{transform::PartialDataset, Dataset};
use std::sync::Arc;

pub struct BatchDataLoader<I, O> {
    strategy: Box<dyn BatchStrategy<I>>,
    dataset: Arc<dyn Dataset<I>>,
    batcher: Arc<dyn Batcher<I, O>>,
}

struct BatchDataloaderIterator<I, O> {
    current_index: usize,
    strategy: Box<dyn BatchStrategy<I>>,
    dataset: Arc<dyn Dataset<I>>,
    batcher: Arc<dyn Batcher<I, O>>,
}

impl<I, O> BatchDataLoader<I, O> {
    pub fn new(
        strategy: Box<dyn BatchStrategy<I>>,
        dataset: Arc<dyn Dataset<I>>,
        batcher: Arc<dyn Batcher<I, O>>,
    ) -> Self {
        Self {
            strategy,
            dataset,
            batcher,
        }
    }
}
impl<I, O> BatchDataLoader<I, O>
where
    I: Send + Sync + Clone + 'static,
    O: Send + Sync + Clone + 'static,
{
    pub fn multi_thread(
        strategy: Box<dyn BatchStrategy<I>>,
        dataset: Arc<dyn Dataset<I>>,
        batcher: Arc<dyn Batcher<I, O>>,
        num_threads: usize,
    ) -> MultiThreadDataLoader<O> {
        let datasets = PartialDataset::split(dataset, num_threads);
        let mut dataloaders: Vec<Arc<dyn DataLoader<_> + Send + Sync>> = Vec::new();
        for dataset in datasets {
            let strategy = strategy.new_like();
            let dataloader = BatchDataLoader::new(strategy, Arc::new(dataset), batcher.clone());
            let dataloader = Arc::new(dataloader);
            dataloaders.push(dataloader);
        }
        MultiThreadDataLoader::new(dataloaders)
    }
}

impl<I, O> DataLoader<O> for BatchDataLoader<I, O> {
    fn iter<'a>(&'a self) -> Box<dyn DataLoaderIterator<O> + 'a> {
        Box::new(BatchDataloaderIterator::new(
            self.strategy.new_like(),
            self.dataset.clone(),
            self.batcher.clone(),
        ))
    }
}

impl<I, O> BatchDataloaderIterator<I, O> {
    pub fn new(
        strategy: Box<dyn BatchStrategy<I>>,
        dataset: Arc<dyn Dataset<I>>,
        batcher: Arc<dyn Batcher<I, O>>,
    ) -> Self {
        BatchDataloaderIterator {
            current_index: 0,
            strategy,
            dataset,
            batcher,
        }
    }
}

impl<I, O> Iterator for BatchDataloaderIterator<I, O> {
    type Item = O;

    fn next(&mut self) -> Option<O> {
        loop {
            let item = self.dataset.get(self.current_index);
            self.current_index += 1;

            let item = match item {
                Some(item) => item,
                None => break,
            };
            self.strategy.add(item);

            if let Some(items) = self.strategy.batch(false) {
                return Some(self.batcher.batch(items));
            }
        }

        if let Some(items) = self.strategy.batch(true) {
            return Some(self.batcher.batch(items));
        }

        None
    }
}

impl<I, O> DataLoaderIterator<O> for BatchDataloaderIterator<I, O> {
    fn progress(&self) -> Progress {
        Progress {
            items_processed: self.current_index,
            items_total: self.dataset.len(),
        }
    }
}

#[cfg(test)]
mod tests {
    use std::collections::HashSet;

    use super::*;
    use crate::data::dataloader::batcher::TestBatcher;
    use crate::data::dataloader::FixBatchStrategy;
    use crate::data::dataset::FakeDataset;

    #[test]
    fn test_batch_dataloader() {
        let batcher = Arc::new(TestBatcher::new());
        let dataset = Arc::new(FakeDataset::<String>::new(27));
        let dataloader =
            BatchDataLoader::new(Box::new(FixBatchStrategy::new(5)), dataset.clone(), batcher);

        let mut items_dataset = HashSet::new();
        let mut items_dataloader = HashSet::new();

        for item in dataset.iter() {
            items_dataset.insert(item);
        }

        for items in dataloader.iter() {
            for item in items {
                items_dataloader.insert(item);
            }
        }

        assert_eq!(items_dataset, items_dataloader);
    }

    #[test]
    fn test_multi_thread_batch_dataloader() {
        let batcher = Arc::new(TestBatcher::new());
        let dataset = Arc::new(FakeDataset::<String>::new(27));
        let dataloader_single_thread = BatchDataLoader::new(
            Box::new(FixBatchStrategy::new(5)),
            dataset.clone(),
            batcher.clone(),
        );
        let dataloader_multi_thread =
            BatchDataLoader::multi_thread(Box::new(FixBatchStrategy::new(5)), dataset, batcher, 4);

        let mut items_single_thread = HashSet::new();
        let mut items_multi_thread = HashSet::new();

        for items in dataloader_single_thread.iter() {
            for item in items {
                items_single_thread.insert(item);
            }
        }

        for items in dataloader_multi_thread.iter() {
            for item in items {
                items_multi_thread.insert(item);
            }
        }

        assert_eq!(items_single_thread, items_multi_thread);
    }
}