espnet.nets.scorers.ctc.CTCPrefixScorer

About 1 min

class espnet.nets.scorers.ctc.CTCPrefixScorer(ctc: Module, eos: int)

Decoder interface wrapper for CTCPrefixScore.

Initialize class.

Parameters:
- ctc (torch.nn.Module) – The CTC implementation. For example, espnet.nets.pytorch_backend.ctc.CTC
- eos (int) – The end-of-sequence id.

batch_init_state(x: Tensor)

Get an initial state for decoding.

Returns: initial state

batch_score_partial(y, ids, state, x)

Score new token.

Parameters:
- y (torch.Tensor) – 1D prefix token
- ids (torch.Tensor) – torch.int64 next token to score
- state – decoder state for prefix tokens
- x (torch.Tensor) – 2D encoder feature that generates ys
Returns: Tuple of a score tensor for y that has a shape (len(next_tokens),) and next state for ys
Return type: tuple[torch.Tensor, Any]

extend_prob(x: Tensor)

Extend probs for decoding.

This extension is for streaming decoding as in Eq (14) in https://arxiv.org/abs/2006.14941

extend_state(state)

Extend state for decoding.

This extension is for streaming decoding as in Eq (14) in https://arxiv.org/abs/2006.14941

Returns: exteded state

init_state(x: Tensor)

Get an initial state for decoding.

Returns: initial state

score_partial(y, ids, state, x)

Score new token.

Parameters:
- y (torch.Tensor) – 1D prefix token
- next_tokens (torch.Tensor) – torch.int64 next token to score
- state – decoder state for prefix tokens
- x (torch.Tensor) – 2D encoder feature that generates ys
Returns: Tuple of a score tensor for y that has a shape (len(next_tokens),) and next state for ys
Return type: tuple[torch.Tensor, Any]

select_state(state, i, new_id=None)

Select state with relative ids in the main beam search.

Parameters:
- state – Decoder state for prefix tokens
- i (int) – Index to select a state in the main beam search
- new_id (int) – New label id to select a state if necessary
Returns: pruned state
Return type: state