How to use DataParallel correctly?

I tested the code on https://pytorch.org/tutorials/beginner/blitz/data_parallel_tutorial.html#sphx-glr-beginner-blitz-data-parallel-tutorial-py. It works well.
But when I changed the code

class Model(nn.Module):
# Our model

def __init__(self, input_size, output_size):
    super(Model, self).__init__()
    self.fc = nn.Linear(input_size, output_size)

def forward(self, input):
    output = self.fc(input)
    print("\tIn Model: input size", input.size(),
          "output size", output.size())

    return output

model = Model(input_size, output_size)

to

model = nn.Linear(input_size, output_size)

,the result became to

. WHY?

Did you wrap your linear layer in nn.DataParallel as well?
Since you are just using an nn.Linear module, the input sizes won’t be printed, which is defined in the original forward method.

Let me know, if I misunderstood your question or what your confusion is about.