| | |
| | | from abc import ABC |
| | | from abc import abstractmethod |
| | | |
| | | |
| | | from funasr.modules.scorers.scorer_interface import BatchScorerInterface |
| | | from typing import Dict |
| | | from typing import Optional |
| | | from typing import Tuple |
| | |
| | | from funasr.torch_utils.device_funcs import force_gatherable |
| | | from funasr.models.base_model import FunASRModel |
| | | |
| | | class AbsLM(torch.nn.Module, BatchScorerInterface, ABC): |
| | | """The abstract LM class |
| | | |
| | | To share the loss calculation way among different models, |
| | | We uses delegate pattern here: |
| | | The instance of this class should be passed to "LanguageModel" |
| | | |
| | | This "model" is one of mediator objects for "Task" class. |
| | | |
| | | """ |
| | | |
| | | @abstractmethod |
| | | def forward( |
| | | self, input: torch.Tensor, hidden: torch.Tensor |
| | | ) -> Tuple[torch.Tensor, torch.Tensor]: |
| | | raise NotImplementedError |
| | | |
| | | |
| | | class LanguageModel(FunASRModel): |
| | | def __init__(self, lm: AbsLM, vocab_size: int, ignore_id: int = 0): |
| | | assert check_argument_types() |
| | | super().__init__() |
| | | self.lm = lm |
| | | self.sos = 1 |
| | | self.eos = 2 |
| | | |
| | | # ignore_id may be assumed as 0, shared with CTC-blank symbol for ASR. |
| | | self.ignore_id = ignore_id |
| | | |
| | | def nll( |
| | | self, |
| | | text: torch.Tensor, |
| | | text_lengths: torch.Tensor, |
| | | max_length: Optional[int] = None, |
| | | ) -> Tuple[torch.Tensor, torch.Tensor]: |
| | | """Compute negative log likelihood(nll) |
| | | |
| | | Normally, this function is called in batchify_nll. |
| | | Args: |
| | | text: (Batch, Length) |
| | | text_lengths: (Batch,) |
| | | max_lengths: int |
| | | """ |
| | | batch_size = text.size(0) |
| | | # For data parallel |
| | | if max_length is None: |
| | | text = text[:, : text_lengths.max()] |
| | | else: |
| | | text = text[:, :max_length] |
| | | |
| | | # 1. Create a sentence pair like '<sos> w1 w2 w3' and 'w1 w2 w3 <eos>' |
| | | # text: (Batch, Length) -> x, y: (Batch, Length + 1) |
| | | x = F.pad(text, [1, 0], "constant", self.sos) |
| | | t = F.pad(text, [0, 1], "constant", self.ignore_id) |
| | | for i, l in enumerate(text_lengths): |
| | | t[i, l] = self.eos |
| | | x_lengths = text_lengths + 1 |
| | | |
| | | # 2. Forward Language model |
| | | # x: (Batch, Length) -> y: (Batch, Length, NVocab) |
| | | y, _ = self.lm(x, None) |
| | | |
| | | # 3. Calc negative log likelihood |
| | | # nll: (BxL,) |
| | | nll = F.cross_entropy(y.view(-1, y.shape[-1]), t.view(-1), reduction="none") |
| | | # nll: (BxL,) -> (BxL,) |
| | | if max_length is None: |
| | | nll.masked_fill_(make_pad_mask(x_lengths).to(nll.device).view(-1), 0.0) |
| | | else: |
| | | nll.masked_fill_( |
| | | make_pad_mask(x_lengths, maxlen=max_length + 1).to(nll.device).view(-1), |
| | | 0.0, |
| | | ) |
| | | # nll: (BxL,) -> (B, L) |
| | | nll = nll.view(batch_size, -1) |
| | | return nll, x_lengths |
| | | |
| | | def batchify_nll( |
| | | self, text: torch.Tensor, text_lengths: torch.Tensor, batch_size: int = 100 |
| | | ) -> Tuple[torch.Tensor, torch.Tensor]: |
| | | """Compute negative log likelihood(nll) from transformer language model |
| | | |
| | | To avoid OOM, this fuction seperate the input into batches. |
| | | Then call nll for each batch and combine and return results. |
| | | Args: |
| | | text: (Batch, Length) |
| | | text_lengths: (Batch,) |
| | | batch_size: int, samples each batch contain when computing nll, |
| | | you may change this to avoid OOM or increase |
| | | |
| | | """ |
| | | total_num = text.size(0) |
| | | if total_num <= batch_size: |
| | | nll, x_lengths = self.nll(text, text_lengths) |
| | | else: |
| | | nlls = [] |
| | | x_lengths = [] |
| | | max_length = text_lengths.max() |
| | | |
| | | start_idx = 0 |
| | | while True: |
| | | end_idx = min(start_idx + batch_size, total_num) |
| | | batch_text = text[start_idx:end_idx, :] |
| | | batch_text_lengths = text_lengths[start_idx:end_idx] |
| | | # batch_nll: [B * T] |
| | | batch_nll, batch_x_lengths = self.nll( |
| | | batch_text, batch_text_lengths, max_length=max_length |
| | | ) |
| | | nlls.append(batch_nll) |
| | | x_lengths.append(batch_x_lengths) |
| | | start_idx = end_idx |
| | | if start_idx == total_num: |
| | | break |
| | | nll = torch.cat(nlls) |
| | | x_lengths = torch.cat(x_lengths) |
| | | assert nll.size(0) == total_num |
| | | assert x_lengths.size(0) == total_num |
| | | return nll, x_lengths |
| | | |
| | | def forward( |
| | | self, text: torch.Tensor, text_lengths: torch.Tensor |
| | | ) -> Tuple[torch.Tensor, Dict[str, torch.Tensor], torch.Tensor]: |
| | | nll, y_lengths = self.nll(text, text_lengths) |
| | | ntokens = y_lengths.sum() |
| | | loss = nll.sum() / ntokens |
| | | stats = dict(loss=loss.detach()) |
| | | |
| | | # force_gatherable: to-device and to-tensor if scalar for DataParallel |
| | | loss, stats, weight = force_gatherable((loss, stats, ntokens), loss.device) |
| | | return loss, stats, weight |
| | | |
| | | def collect_feats( |
| | | self, text: torch.Tensor, text_lengths: torch.Tensor |
| | | ) -> Dict[str, torch.Tensor]: |
| | | return {} |
| | | |
| | | |
| | | class PunctuationModel(FunASRModel): |
| | | |