TypeError: cannot unpack non-iterable DataParallel object
时间: 2024-01-17 20:17:07 浏览: 168
Unit-18-Practical-task
TypeError: cannot unpack non-iterable DataParallel object通常是由于在使用PyTorch的DataParallel时,未正确设置模型的输出。DataParallel将模型复制到多个GPU上,并将输入数据分成多个部分,以便在多个GPU上并行处理。但是,如果模型的输出不是可迭代的对象,则会出现此错误。
以下是解决此错误的两种方法:
1.在模型输出之前使用`.item()`方法将输出转换为标量值。例如:
```python
import torch
import torch.nn as nn
from torch.utils.data import DataLoader
# 定义模型
class MyModel(nn.Module):
def __init__(self):
super(MyModel, self).__init__()
self.linear = nn.Linear(10, 1)
def forward(self, x):
return self.linear(x)
# 定义数据集
class MyDataset(torch.utils.data.Dataset):
def __init__(self):
self.data = torch.randn(100, 10)
self.targets = torch.randn(100, 1)
def __getitem__(self, index):
x = self.data[index]
y = self.targets[index]
return x, y
def __len__(self):
return len(self.data)
# 初始化模型和数据集
model = MyModel()
dataset = MyDataset()
# 使用DataParallel
model = nn.DataParallel(model)
dataloader = DataLoader(dataset, batch_size=10)
# 训练模型
for data in dataloader:
inputs, targets = data
outputs = model(inputs)
loss = nn.MSELoss()(outputs, targets)
loss.backward()
optimizer.step()
# 将输出转换为标量值
outputs = outputs.item()
print(outputs)
```
2.在模型输出之前使用`.mean()`方法将输出转换为平均值。例如:
```python
import torch
import torch.nn as nn
from torch.utils.data import DataLoader
# 定义模型
class MyModel(nn.Module):
def __init__(self):
super(MyModel, self).__init__()
self.linear = nn.Linear(10, 1)
def forward(self, x):
return self.linear(x)
# 定义数据集
class MyDataset(torch.utils.data.Dataset):
def __init__(self):
self.data = torch.randn(100, 10)
self.targets = torch.randn(100, 1)
def __getitem__(self, index):
x = self.data[index]
y = self.targets[index]
return x, y
def __len__(self):
return len(self.data)
# 初始化模型和数据集
model = MyModel()
dataset = MyDataset()
# 使用DataParallel
model = nn.DataParallel(model)
dataloader = DataLoader(dataset, batch_size=10)
# 训练模型
for data in dataloader:
inputs, targets = data
outputs = model(inputs)
loss = nn.MSELoss()(outputs, targets)
loss.backward()
optimizer.step()
# 将输出转换为平均值
outputs = torch.mean(outputs)
print(outputs)
```
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