出错:

Traceback (most recent call last):
 File "train.py", line 305, in <module>
 train_model(model_conv, criterion, optimizer_conv, exp_lr_scheduler)
 File "train.py", line 145, in train_model
 for inputs, age_labels, gender_labels in dataloaders[phase]:
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 637, in __next__
 return self._process_next_batch(batch)
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 658, in _process_next_batch
 raise batch.exc_type(batch.exc_msg)
RuntimeError: Traceback (most recent call last):
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 138, in _worker_loop
 samples = collate_fn([dataset[i] for i in batch_indices])
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 232, in default_collate
 return [default_collate(samples) for samples in transposed]
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 232, in <listcomp>
 return [default_collate(samples) for samples in transposed]
 File "/home/home/anaconda3/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 209, in default_collate
 return torch.stack(batch, 0, out=out)
RuntimeError: invalid argument 0: Sizes of tensors must match except in dimension 0. Got 224 and 228 in dimension 3 at /pytorch/aten/src/TH/generic/THTensorMoreMath.cpp:1307

这是因为输入的大小不匹配,跟数据集有关,也跟数据预处理中的函数相关:

transforms.Resize(input_size)

该函数是按比例缩放,可能是因为该数据集的分辨率不同,所以出来的结果不是(224,224)的,解决办法是改为使用:

transforms.Resize((input_size, input_size))

即可