DeepSpeech/native_client/ctcdecode/ctc_beam_search_decoder.h
2018-10-25 22:28:48 -03:00

65 lines
2.2 KiB
C++

#ifndef CTC_BEAM_SEARCH_DECODER_H_
#define CTC_BEAM_SEARCH_DECODER_H_
#include <string>
#include <utility>
#include <vector>
#include "scorer.h"
#include "output.h"
#include "alphabet.h"
/* CTC Beam Search Decoder
* Parameters:
* probs_seq: 2-D vector that each element is a vector of probabilities
* over vocabulary of one time step.
* vocabulary: A vector of vocabulary.
* beam_size: The width of beam search.
* cutoff_prob: Cutoff probability for pruning.
* cutoff_top_n: Cutoff number for pruning.
* ext_scorer: External scorer to evaluate a prefix, which consists of
* n-gram language model scoring and word insertion term.
* Default null, decoding the input sample without scorer.
* Return:
* A vector that each element is a pair of score and decoding result,
* in desending order.
*/
std::vector<std::pair<double, Output>> ctc_beam_search_decoder(
const std::vector<std::vector<double>> &probs_seq,
const Alphabet &vocabulary,
size_t beam_size,
double cutoff_prob = 1.0,
size_t cutoff_top_n = 40,
Scorer *ext_scorer = nullptr);
/* CTC Beam Search Decoder for batch data
* Parameters:
* probs_seq: 3-D vector that each element is a 2-D vector that can be used
* by ctc_beam_search_decoder().
* vocabulary: A vector of vocabulary.
* beam_size: The width of beam search.
* num_processes: Number of threads for beam search.
* cutoff_prob: Cutoff probability for pruning.
* cutoff_top_n: Cutoff number for pruning.
* ext_scorer: External scorer to evaluate a prefix, which consists of
* n-gram language model scoring and word insertion term.
* Default null, decoding the input sample without scorer.
* Return:
* A 2-D vector that each element is a vector of beam search decoding
* result for one audio sample.
*/
std::vector<std::vector<std::pair<double, Output>>>
ctc_beam_search_decoder_batch(
const std::vector<std::vector<std::vector<double>>> &probs_split,
const Alphabet &vocabulary,
size_t beam_size,
size_t num_processes,
double cutoff_prob = 1.0,
size_t cutoff_top_n = 40,
Scorer *ext_scorer = nullptr);
#endif // CTC_BEAM_SEARCH_DECODER_H_