RuntimeError: The expanded size of the tensor (1) must match the existing size (3) at non-singleton dimension 0 about pytorch-cyclegan HOT 2 OPEN

I also encountered this problem. It may be that some images in the data set are grayscale images instead of rgb images. I deleted these grayscale images to solve this problem.
Here is my code.
`def remove_single_channel_images(images_files):
for path in sorted(os.listdir(images_files)):
image_path = os.path.join(images_files, path)
image = Image.open(image_path)
image = np.array(image)
if image.shape != (256, 256, 3):
print(image_path)
os.remove(image_path)

remove_single_channel_images('datasets/horse2zebra/train/B')`

from pytorch-cyclegan.

The main reason for this problem is that there are single channel images in the data set. Solution: just add. convert ('rgb ') in datasets.py file
iterm_B = self.transform(Image.open(self.files_B[random.randint(0, len(self.files_B)-1)]).convert('RGB'))

from pytorch-cyclegan.