#

测试优化器的 MNIST 示例

9import torch.nn as nn
10import torch.utils.data
11from labml_helpers.module import Module
12
13from labml import experiment, tracker
14from labml.configs import option
15from labml_helpers.datasets.mnist import MNISTConfigs
16from labml_helpers.device import DeviceConfigs
17from labml_helpers.metrics.accuracy import Accuracy
18from labml_helpers.seed import SeedConfigs
19from labml_helpers.train_valid import TrainValidConfigs, BatchIndex, hook_model_outputs
20from labml_nn.optimizers.configs import OptimizerConfigs

#

该模型

23class Model(Module):

#

27    def __init__(self):
28        super().__init__()
29        self.conv1 = nn.Conv2d(1, 20, 5, 1)
30        self.pool1 = nn.MaxPool2d(2)
31        self.conv2 = nn.Conv2d(20, 50, 5, 1)
32        self.pool2 = nn.MaxPool2d(2)
33        self.fc1 = nn.Linear(16 * 50, 500)
34        self.fc2 = nn.Linear(500, 10)
35        self.activation = nn.ReLU()

#

37    def forward(self, x):
38        x = self.activation(self.conv1(x))
39        x = self.pool1(x)
40        x = self.activation(self.conv2(x))
41        x = self.pool2(x)
42        x = self.activation(self.fc1(x.view(-1, 16 * 50)))
43        return self.fc2(x)

#

可配置的实验定义

46class Configs(MNISTConfigs, TrainValidConfigs):

#

50    optimizer: torch.optim.Adam
51    model: nn.Module
52    set_seed = SeedConfigs()
53    device: torch.device = DeviceConfigs()
54    epochs: int = 10
55
56    is_save_models = True
57    model: nn.Module
58    inner_iterations = 10
59
60    accuracy_func = Accuracy()
61    loss_func = nn.CrossEntropyLoss()

#

63    def init(self):
64        tracker.set_queue("loss.*", 20, True)
65        tracker.set_scalar("accuracy.*", True)
66        hook_model_outputs(self.mode, self.model, 'model')
67        self.state_modules = [self.accuracy_func]

#

69    def step(self, batch: any, batch_idx: BatchIndex):

#

获取批次

71        data, target = batch[0].to(self.device), batch[1].to(self.device)

#

如果我们处于训练模式，则添加全局步长

74        if self.mode.is_train:
75            tracker.add_global_step(len(data))

#

运行模型并指定是否记录激活

78        with self.mode.update(is_log_activations=batch_idx.is_last):
79            output = self.model(data)

#

计算损失

82        loss = self.loss_func(output, target)

#

计算精度

84        self.accuracy_func(output, target)

#

记录损失

86        tracker.add("loss.", loss)

#

如果我们处于训练模式，请进行优化

89        if self.mode.is_train:

#

计算梯度

91            loss.backward()

#

采取优化器步骤

94            self.optimizer.step()

#

每个纪元记录一次参数和梯度 L2 规范

96            if batch_idx.is_last:
97                tracker.add('model', self.model)
98                tracker.add('optimizer', (self.optimizer, {'model': self.model}))

#

清除渐变

100            self.optimizer.zero_grad()

#

保存日志

103        tracker.save()

#

创建可配置的优化器。我们可以使用配置更改优化器类型和超参数。

106@option(Configs.model)
107def model(c: Configs):
108    return Model().to(c.device)
109
110
111@option(Configs.optimizer)
112def _optimizer(c: Configs):

#

117    opt_conf = OptimizerConfigs()
118    opt_conf.parameters = c.model.parameters()
119    return opt_conf

#

122def main():
123    conf = Configs()
124    conf.inner_iterations = 10
125    experiment.create(name='mnist_ada_belief')
126    experiment.configs(conf, {'inner_iterations': 10,

#

指定优化器

128                              'optimizer.optimizer': 'Adam',
129                              'optimizer.learning_rate': 1.5e-4})
130    conf.set_seed.set()
131    experiment.add_pytorch_models(dict(model=conf.model))
132    with experiment.start():
133        conf.run()
134
135
136if __name__ == '__main__':
137    main()