al*, returned when `start_positions`, `end_positions`, `has_answers` are provided): Retriever loss. reader_loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `start_positions`, `end_positions`, `has_answers` are provided): Reader loss. retriever_correct (`torch.BoolTensor` of shape `(config.searcher_beam_size,)`, *optional*): Whether or not an evidence block contains answer. reader_correct (`torch.BoolTensor` of shape `(config.reader_beam_size, num_candidates)`, *optional*): Whether or not a span candidate contains answer. block_idx (`torch.LongTensor` of shape `()`): The index of the retrieved evidence block in which the predicted answer is most likely. candidate (`torch.LongTensor` of shape `()`): The index of the retrieved span candidates in which the predicted answer is most likely. start_pos (`torch.IntTensor` of shape `()`): Predicted answer starting position in *RealmReader*'s inputs. end_pos (`torch.IntTensor` of shape `()`): Predicted answer ending position in *RealmReader*'s inputs. hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of shape `(batch_size, sequence_length, hidden_size)`. Hidden-states of the model at the output of each layer plus the initial embedding outputs. attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, sequence_length)`. Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads. NÚ