[FIXED] Turning variable into a torch Tensor. Afterwards tensor is empty / has no element

Issue

The following is my Code. The "sequences" are my training data in the form [139 rows x 4 columns], 0) where the 139x4 are my signals and the 0 is my encoded label.

    def __getitem__(self, idx):
      sequence, label = self.sequences[idx]
  
      #converting sequence and label to tensors 
      sequence = torch.Tensor(sequence.to_numpy())
      
      print("label before tensor", label)
      label = torch.Tensor(label).long()
      print("numel() labels   :", label.numel())
      print("label shape    :", shape(label))
      return (sequence, label) 

The Code output is:

      >>label bevore tensor 0  (This is my encoded label)
      >>numel() labels   : 0
      >>label shape    : torch.Size([0])

Why is my label tensor empty?

Solution

Because torch.Tensor expects either an array (in which case this array becomes the underlying values) or several ints which will be the size of the tensor. Hence torch.Tensor(0) instantiates a tensor of size 0.

Either you use torch.Tensor([0]) or torch.tensor(0). Why these two objects behave in a different manner I don't know, but I'd recommend using the tensor (not capitalized) since it's better documented (the Tensor one seems to be part of the C port)

edit : found this useful thread about their difference

Answered By - trialNerror