NotImplementedError in torch_geometric.data.Dataset

[skyqwe123]

When i create a dataset like this， An error has occurred。

class P2MDataSet(Dataset):
……
def process(self):
       ……
       data = Data(y=img_data, pos=mesh_data[:, :3], norm=mesh_data[:, 3:])
       torch.save(data, pt_file)

def get(self, idx):
    data = self.processed_paths[idx]   ===self.processed_ Paths are normal
    print(data)
    return torch.load(data)

dataset = P2MDataSet('./datasets/sp2') （√）
print(dataset[0]) （×） error in here

Traceback (most recent call last):
File "/share/users/lihuimin/pro/cpy/datasets/p2m_dataset.py", line 131, in
print(dataset[0])
File "/data/lihuimin/.conda/envs/cv/lib/python3.9/site-packages/torch_geometric/data/dataset.py", line 197, in getitem
data = self.get(self.indices()[idx])
File "/data/lihuimin/.conda/envs/cv/lib/python3.9/site-packages/torch_geometric/data/dataset.py", line 90, in indices
return range(self.len()) if self._indices is None else self._indices
File "/data/lihuimin/.conda/envs/cv/lib/python3.9/site-packages/torch_geometric/data/dataset.py", line 62, in len
raise NotImplementedError
NotImplementedError

Process finished with exit code 1

[rusty1s]

You also need to implement the len function which should return the number of examples/graph in your dataset:

def len(self) -> int:
    ...  # return number of examples