|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
declare(strict_types=1); |
|
4
|
|
|
|
|
5
|
|
|
namespace Phpml\Dataset; |
|
6
|
|
|
|
|
7
|
|
|
use Phpml\Exception\InvalidArgumentException; |
|
8
|
|
|
|
|
9
|
|
|
/** |
|
10
|
|
|
* MNIST dataset: http://yann.lecun.com/exdb/mnist/ |
|
11
|
|
|
* original mnist dataset reader: https://github.com/AndrewCarterUK/mnist-neural-network-plain-php |
|
12
|
|
|
*/ |
|
13
|
|
|
final class MnistDataset extends ArrayDataset |
|
14
|
|
|
{ |
|
15
|
|
|
private const MAGIC_IMAGE = 0x00000803; |
|
16
|
|
|
|
|
17
|
|
|
private const MAGIC_LABEL = 0x00000801; |
|
18
|
|
|
|
|
19
|
|
|
private const IMAGE_ROWS = 28; |
|
20
|
|
|
|
|
21
|
|
|
private const IMAGE_COLS = 28; |
|
22
|
|
|
|
|
23
|
|
|
public function __construct(string $imagePath, string $labelPath) |
|
24
|
|
|
{ |
|
25
|
|
|
$this->samples = $this->readImages($imagePath); |
|
26
|
|
|
$this->targets = $this->readLabels($labelPath); |
|
27
|
|
|
|
|
28
|
|
|
if (count($this->samples) !== count($this->targets)) { |
|
29
|
|
|
throw new InvalidArgumentException('Must have the same number of images and labels'); |
|
30
|
|
|
} |
|
31
|
|
|
} |
|
32
|
|
|
|
|
33
|
|
|
private function readImages(string $imagePath): array |
|
34
|
|
|
{ |
|
35
|
|
|
$stream = fopen($imagePath, 'rb'); |
|
36
|
|
|
|
|
37
|
|
|
if ($stream === false) { |
|
38
|
|
|
throw new InvalidArgumentException('Could not open file: '.$imagePath); |
|
39
|
|
|
} |
|
40
|
|
|
|
|
41
|
|
|
$images = []; |
|
42
|
|
|
|
|
43
|
|
|
try { |
|
44
|
|
|
$header = fread($stream, 16); |
|
45
|
|
|
|
|
46
|
|
|
$fields = unpack('Nmagic/Nsize/Nrows/Ncols', (string) $header); |
|
47
|
|
|
|
|
48
|
|
|
if ($fields['magic'] !== self::MAGIC_IMAGE) { |
|
49
|
|
|
throw new InvalidArgumentException('Invalid magic number: '.$imagePath); |
|
50
|
|
|
} |
|
51
|
|
|
|
|
52
|
|
|
if ($fields['rows'] != self::IMAGE_ROWS) { |
|
53
|
|
|
throw new InvalidArgumentException('Invalid number of image rows: '.$imagePath); |
|
54
|
|
|
} |
|
55
|
|
|
|
|
56
|
|
|
if ($fields['cols'] != self::IMAGE_COLS) { |
|
57
|
|
|
throw new InvalidArgumentException('Invalid number of image cols: '.$imagePath); |
|
58
|
|
|
} |
|
59
|
|
|
|
|
60
|
|
|
for ($i = 0; $i < $fields['size']; $i++) { |
|
61
|
|
|
$imageBytes = fread($stream, $fields['rows'] * $fields['cols']); |
|
62
|
|
|
|
|
63
|
|
|
// Convert to float between 0 and 1 |
|
64
|
|
|
$images[] = array_map(function ($b) { |
|
65
|
|
|
return $b / 255; |
|
66
|
|
|
}, array_values(unpack('C*', (string) $imageBytes))); |
|
|
|
|
|
|
67
|
|
|
} |
|
68
|
|
|
} finally { |
|
69
|
|
|
fclose($stream); |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
return $images; |
|
73
|
|
|
} |
|
74
|
|
|
|
|
75
|
|
|
private function readLabels(string $labelPath): array |
|
76
|
|
|
{ |
|
77
|
|
|
$stream = fopen($labelPath, 'rb'); |
|
78
|
|
|
|
|
79
|
|
|
if ($stream === false) { |
|
80
|
|
|
throw new InvalidArgumentException('Could not open file: '.$labelPath); |
|
81
|
|
|
} |
|
82
|
|
|
|
|
83
|
|
|
$labels = []; |
|
84
|
|
|
|
|
85
|
|
|
try { |
|
86
|
|
|
$header = fread($stream, 8); |
|
87
|
|
|
|
|
88
|
|
|
$fields = unpack('Nmagic/Nsize', (string) $header); |
|
89
|
|
|
|
|
90
|
|
|
if ($fields['magic'] !== self::MAGIC_LABEL) { |
|
91
|
|
|
throw new InvalidArgumentException('Invalid magic number: '.$labelPath); |
|
92
|
|
|
} |
|
93
|
|
|
|
|
94
|
|
|
$labels = fread($stream, $fields['size']); |
|
95
|
|
|
} finally { |
|
96
|
|
|
fclose($stream); |
|
97
|
|
|
} |
|
98
|
|
|
|
|
99
|
|
|
return array_values(unpack('C*', (string) $labels)); |
|
|
|
|
|
|
100
|
|
|
} |
|
101
|
|
|
} |
|
102
|
|
|
|
php-ai /
php-ml
Loading history...