def ctc_beam_search_decoder(probs_seq,
vocabulary,
beam_size,
cutoff_prob=1.0,
cutoff_top_n=40,
blank_id=0,
ext_scoring_func=None):
"""集束搜索解码器
:param probs_seq: 单个2-D概率分布列表，每个元素是词汇表和空白上的标准化概率列表
:type probs_seq: 2-D list
:param vocabulary: 词汇列表
:type vocabulary: list
:param beam_size: 集束搜索宽度
:type beam_size: int
:param cutoff_prob: 剪枝中的截断概率，默认1.0，没有剪枝
:type cutoff_prob: float
:param cutoff_top_n: 剪枝时的截断数，仅在词汇表中具有最大probs的cutoff_top_n字符用于光束搜索，默认为40
:type cutoff_top_n: int
:param blank_id 空白索引
:type blank_id int
:param ext_scoring_func: 外部评分功能部分解码句子，如字计数或语言模型
:type external_scoring_func: callable
:return: 解码结果为log概率和句子的元组列表，按概率降序排列
:rtype: list
"""
beam_results = swig_decoders.ctc_beam_search_decoder(
probs_seq.tolist(), vocabulary, beam_size, cutoff_prob, cutoff_top_n,
blank_id, ext_scoring_func)
beam_results = [(res[0], res[1]) for res in beam_results]
return beam_results
def ctc_beam_search_decoder(probs_seq,
vocabulary,
beam_size,
cutoff_prob=1.0,
cutoff_top_n=40,
ext_scoring_func=None):
"""Wrapper for the CTC Beam Search Decoder.
:param probs_seq: 2-D list of probability distributions over each time
step, with each element being a list of normalized
probabilities over vocabulary and blank.
:type probs_seq: 2-D list
:param vocabulary: Vocabulary list.
:type vocabulary: list
:param beam_size: Width for beam search.
:type beam_size: int
:param cutoff_prob: Cutoff probability in pruning,
default 1.0, no pruning.
:type cutoff_prob: float
:param cutoff_top_n: Cutoff number in pruning, only top cutoff_top_n
characters with highest probs in vocabulary will be
used in beam search, default 40.
:type cutoff_top_n: int
:param ext_scoring_func: External scoring function for
partially decoded sentence, e.g. word count
or language model.
:type external_scoring_func: callable
:return: List of tuples of log probability and sentence as decoding
results, in descending order of the probability.
:rtype: list
"""
beam_results = swig_decoders.ctc_beam_search_decoder(
probs_seq.tolist(), vocabulary, beam_size, cutoff_prob, cutoff_top_n,
ext_scoring_func)
beam_results = [(res[0], res[1]) for res in beam_results]
# python2.7
# beam_results = [(res[0], res[1].decode('utf-8')) for res in beam_results]
return beam_results