使用MindTorch
使用MindTorch迁移PyTorch网络前,第一步是替换导入模块路径。
方式一:一行代码自动替换(推荐)
用户只需要在PyTorch源代码主入口调用torch
系列相关的包导入部分之前调用from mindtorch.tools import mstorch_enable
,代码执行时torch同名的导入模块会自动被转换为mindtorch相应的模块(目前支持torch、torchvision、torchaudio
相关模块的自动转换)。
from mindtorch.tools import mstorch_enable # 需要在主入口文件导入torch相关模块的前面使用
import torch
from torch import nn
from torch.utils.data import DataLoader
from torchvision import datasets
from torchvision.transforms import ToTensor
# 1.Working with data
# Download training data from open datasets.
training_data = datasets.FashionMNIST(root="data", train=True, download=True, transform=ToTensor())
# Download test data from open datasets.
test_data = datasets.FashionMNIST(root="data", train=False, download=True, transform=ToTensor())
# 2.Creating Models
class NeuralNetwork(nn.Module):
def __init__(self):
super().__init__()
self.flatten = nn.Flatten()
self.linear_relu_stack = nn.Sequential(
nn.Linear(28*28, 512),
nn.ReLU(),
nn.Linear(512, 512),
nn.ReLU(),
nn.Linear(512, 10)
)
def forward(self, x):
x = self.flatten(x)
logits = self.linear_relu_stack(x)
return logits
def train(dataloader, model, loss_fn, optimizer, device):
size = len(dataloader.dataset)
model.train()
for batch, (X, y) in enumerate(dataloader):
X, y = X.to(device), y.to(device)
# Compute prediction error
pred = model(X)
loss = loss_fn(pred, y)
# Backpropagation
loss.backward()
optimizer.step()
optimizer.zero_grad()
if batch % 100 == 0:
loss, current = loss.item(), (batch + 1) * len(X)
print(f"loss: {loss:>7f} [{current:>5d}/{size:>5d}]")
def test(dataloader, model, loss_fn, device):
size = len(dataloader.dataset)
num_batches = len(dataloader)
model.eval()
test_loss, correct = 0, 0
with torch.no_grad():
for X, y in dataloader:
X, y = X.to(device), y.to(device)
pred = model(X)
test_loss += loss_fn(pred, y).item()
correct += (pred.argmax(1) == y).type(torch.float).sum().item()
test_loss /= num_batches
correct /= size
print(f"Test Error: \n Accuracy: {(100*correct):>0.1f}%, Avg loss: {test_loss:>8f} \n")
if __name__ == '__main__':
train_dataloader = DataLoader(training_data, batch_size=64)
test_dataloader = DataLoader(test_data, batch_size=64)
# Get cpu, gpu or mps device for training.
device = (
"cuda"
if torch.cuda.is_available()
else "mps"
if torch.backends.mps.is_available()
else "cpu"
)
model = NeuralNetwork().to(device)
# 3.Optimizing the Model Parameters
loss_fn = nn.CrossEntropyLoss()
optimizer = torch.optim.SGD(model.parameters(), lr=1e-3)
epochs = 5
for t in range(epochs):
print(f"Epoch {t+1}\n-------------------------------")
train(train_dataloader, model, loss_fn, optimizer, device)
test(test_dataloader, model, loss_fn, device)
print("Done!")
# 4.Saving Models
torch.save(model.state_dict(), "model.pth")
print("Saved PyTorch Model State to model.pth")
# 5.Loading Models
model = NeuralNetwork().to(device)
model.load_state_dict(torch.load("model.pth"))
classes = [
"T-shirt/top",
"Trouser",
"Pullover",
"Dress",
"Coat",
"Sandal",
"Shirt",
"Sneaker",
"Bag",
"Ankle boot",
]
# 6.Predicted
model.eval()
x, y = test_data[0][0], test_data[0][1]
with torch.no_grad():
x = x.to(device)
pred = model(x)
predicted, actual = classes[pred[0].argmax(0)], classes[y]
print(f'Predicted: "{predicted}", Actual: "{actual}"')
方式二:工具手动预先替换
替换代码中导入torch
相关包的代码,可以利用mindtorch/tools下提供的replace_import_package工具可快速完成工程代码中torch及torchvision相关导入包的替换。
bash replace_import_package.sh [Project Path]
Project Path
为需要进行替换的工程路经,默认为"./"。
或者,用户也可以逐文件手动的替换文件中的导入包部分代码,示例代码如下:
# 替换前
# import torch
# import torch.nn as nn
# import torch.nn.functional as F
# from torchvision import datasets, transforms
# 替换后
import mindtorch.torch as torch
import mindtorch.torch.nn as nn
import mindtorch.torch.nn.functional as F
from mindtorch.torchvision import datasets, transforms
MindTorch目前已支持大部分PyTorch和TorchVision的原生态表达接口,如果在import阶段遇到有不支持的模块或接口报错,可以通过创建ISSUE 向我们反馈,我们会优先支持。