representations.py 文件源码

def user_representation(self, item_sequences):
        """
        Compute user representation from a given sequence.

        Returns
        -------

        tuple (all_representations, final_representation)
            The first element contains all representations from step
            -1 (no items seen) to t - 1 (all but the last items seen).
            The second element contains the final representation
            at step t (all items seen). This final state can be used
            for prediction or evaluation.
        """

        # Make the embedding dimension the channel dimension
        sequence_embeddings = (self.item_embeddings(item_sequences)
                               .permute(0, 2, 1))
        # Add a trailing dimension of 1
        sequence_embeddings = (sequence_embeddings
                               .unsqueeze(3))
        # Pad it with zeros from left
        sequence_embeddings = (F.pad(sequence_embeddings,
                                     (0, 0, 1, 0))
                               .squeeze(3))
        sequence_embeddings = sequence_embeddings.permute(0, 2, 1)

        user_representations, _ = self.lstm(sequence_embeddings)
        user_representations = user_representations.permute(0, 2, 1)

        return user_representations[:, :, :-1], user_representations[:, :, -1]