(self, src, lengths=None)
Args:
            src (:obj:`LongTensor`):
               padded sequences of sparse indices `[src_len x batch x nfeat]`
            lengths (:obj:`LongTensor`): length of each sequence `[batch]`


        Returns:
            (tuple of :obj:`FloatTensor`, :obj:`FloatTensor`):
                * final encoder state, used to initialize decoder
                * memory bank for attention, `[src_len x batch x hidden]`
Args:
            src (:obj:`LongTensor`):
               padded sequences of sparse indices `[src_len x batch x nfeat]`
            lengths (:obj:`LongTensor`): length of each sequence `[batch]`
Args : src ( : obj : LongTensor ) : padded sequences of sparse indices [ src_len x batch x nfeat ] lengths ( : obj : LongTensor ) : length of each sequence [ batch ]
def forward(self, src, lengths=None):
        """
        Args:
            src (:obj:`LongTensor`):
               padded sequences of sparse indices `[src_len x batch x nfeat]`
            lengths (:obj:`LongTensor`): length of each sequence `[batch]`


        Returns:
            (tuple of :obj:`FloatTensor`, :obj:`FloatTensor`):
                * final encoder state, used to initialize decoder
                * memory bank for attention, `[src_len x batch x hidden]`
        """
        raise NotImplementedError
def forward ( self , src , lengths = None ) : raise NotImplementedError