Thanks rasbt. Your explanation makes sense. In the line it’s complaining about, I’m not setting any sizes except for the size of the sparse vector, which is always ~8000. It’s set once and none of the other data loaders are upset. So how do I interpret this in the context of my code?
X = torch.sparse.FloatTensor(
            torch.LongTensor([self.i[ID]]),
            torch.FloatTensor(self.v[ID]), 
            torch.Size([self.vecSize])
        ).to_dense()
        i = self.labels[ID]