Merge pull request '增加两卡gpu并行训练示例' (#35) from liuzx into master

Reviewed-on: https://openi.pcl.ac.cn/OpenIOSSG/OpenI_Cloudbrain_Example/pulls/35

gpu_mnist_example/parallel_train.py

@@ -0,0 +1,133 @@
+#!/usr/bin/python
+#coding=utf-8
+'''
+If there are Chinese comments in the code，please add at the beginning：
+#!/usr/bin/python
+#coding=utf-8   
+
+数据集结构是：
+ MnistDataset_torch.zip
+  ├── test
+  └── train  
+
+预训练模型文件夹结构是：
+Torch_MNIST_Example_Model
+├── mnist_epoch1.pkl
+
+'''
+
+
+from model import Model
+import numpy as np
+import torch
+import torch.nn as nn
+from torchvision.datasets import mnist
+from torch.nn import CrossEntropyLoss
+from torch.optim import SGD
+from torch.utils.data import DataLoader
+from torchvision.transforms import ToTensor
+import argparse
+import os
+os.system("pip install c2net")
+#导入c2net包
+from c2net.context import prepare
+
+# Training settings
+parser = argparse.ArgumentParser(description='PyTorch MNIST Example')
+parser.add_argument('--epoch_size', type=int, default=10, help='how much epoch to train')
+parser.add_argument('--batch_size', type=int, default=256, help='how much batch_size in epoch')
+
+# 参数声明
+WORKERS = 0   # dataloder线程数
+
+# 检查可用GPU数量
+if torch.cuda.device_count() < 2:
+    raise RuntimeError("需要至少2块GPU，但当前只有 {} 块".format(torch.cuda.device_count()))
+else:
+    print('当前有 {} 块GPU'.format(torch.cuda.device_count()))  
+device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+
+# 2. 初始化模型并并行化
+model = Model().to(device)
+
+print('开始进行并行训练！')  
+model = nn.DataParallel(model, device_ids=[0, 1])  # 使用GPU 0和1
+
+optimizer = SGD(model.parameters(), lr=1e-1)
+cost = CrossEntropyLoss()
+
+# 模型训练
+def train(model, train_loader, epoch):
+    model.train()
+    train_loss = 0
+    for i, data in enumerate(train_loader, 0):
+        x, y = data
+        x = x.to(device)
+        y = y.to(device)
+        optimizer.zero_grad()
+        y_hat = model(x)
+        loss = cost(y_hat, y)
+        loss.backward()
+        optimizer.step()
+        train_loss += loss
+    loss_mean = train_loss / (i+1)
+    print('Train Epoch: {}\t Loss: {:.6f}'.format(epoch, loss_mean.item()))
+ 
+# 模型测试
+def test(model, test_loader, test_data):
+    model.eval()
+    test_loss = 0
+    correct = 0
+    with torch.no_grad():
+        for i, data in enumerate(test_loader, 0):
+            x, y = data
+            x = x.to(device)
+            y = y.to(device)
+            optimizer.zero_grad()
+            y_hat = model(x)
+            test_loss += cost(y_hat, y).item()
+            pred = y_hat.max(1, keepdim=True)[1]
+            correct += pred.eq(y.view_as(pred)).sum().item()
+        test_loss /= (i+1)
+        print('Test set: Average loss: {:.4f}, Accuracy: {}/{} ({:.0f}%)\n'.format(
+            test_loss, correct, len(test_data), 100. * correct / len(test_data)))
+
+if __name__ == '__main__':
+    args, unknown = parser.parse_known_args()
+
+    #初始化导入数据集和预训练模型到容器内
+    c2net_context = prepare()
+    #获取数据集路径
+    MnistDataset_torch_path = c2net_context.dataset_path+"/"+"MnistDataset_torch"
+    #获取预训练模型路径
+    Torch_MNIST_Example_Model_path = c2net_context.pretrain_model_path+"/"+"Torch_MNIST_Example_Model"
+
+    #log output
+    print('cuda is available:{}'.format(torch.cuda.is_available()))  
+    device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
+    batch_size = args.batch_size
+    epochs = args.epoch_size
+    train_dataset = mnist.MNIST(root=os.path.join(MnistDataset_torch_path, "train"), train=True, transform=ToTensor(),download=False)
+#     test_dataset = mnist.MNIST(root=os.path.join(MnistDataset_torch_path, "test"), train=False, transform=ToTensor(),download=False)
+    train_loader = DataLoader(train_dataset, batch_size=batch_size)
+#     test_loader = DataLoader(test_dataset, batch_size=batch_size)
+
+    #如果有保存的模型，则加载模型，并在其基础上继续训练
+    if os.path.exists(os.path.join(Torch_MNIST_Example_Model_path, "mnist_epoch1.pkl")):
+        checkpoint = torch.load(os.path.join(Torch_MNIST_Example_Model_path, "mnist_epoch1.pkl"))
+        model.load_state_dict(checkpoint['model'])
+        optimizer.load_state_dict(checkpoint['optimizer'])
+        start_epoch = checkpoint['epoch']
+        print('加载 epoch {} 权重成功！'.format(start_epoch))
+    else:
+        start_epoch = 0
+        print('无保存模型，将从头开始训练！')
+ 
+    for epoch in range(start_epoch+1, epochs+1):
+        train(model, train_loader, epoch)
+#         test(model, test_loader, test_dataset)
+        # 将模型保存到c2net_context.output_path
+        state = {'model':model.state_dict(), 'optimizer':optimizer.state_dict(), 'epoch':epoch}
+        torch.save(state, '{}/mnist_epoch{}.pkl'.format(c2net_context.output_path, epoch))
+
+