Hi, thank you for your remind. That’s what I’m wondering. I watched the tutorial of torch.utils.data.Dataset and  torch.utils.data.DataLoader. But I’m not very sure in that way single mini-batch is supplied for train model.
I mean for X with torch.Size([32, 500, 60, 2130]),
for step, (batch_x, batch_y) in enumerate(dataloader):

is batch_x in shape torch.Size([1, 500, 60, 2130])? And do I have to send it to GPU manually in the train part?
By the way, why doesn’t pytorch do like Keras, automatically load batches in RAM, and send single batch to GPU. Since GPU memory is the obvious bottleneck now, no one can use large dataset in GPU memory. Why would pytorch leave this to users? Sorry if my question is too silly. I’m new to pytorch.