tok

Tokenization.

class hanlp.components.mtl.tasks.tok.tag_tok.TaggingTokenization(trn: str = None, dev: str = None, tst: str = None, sampler_builder: hanlp.common.dataset.SamplerBuilder = None, dependencies: str = None, scalar_mix: hanlp.layers.scalar_mix.ScalarMixWithDropoutBuilder = None, use_raw_hidden_states=False, lr=0.001, separate_optimizer=False, cls_is_bos=True, sep_is_eos=True, delimiter=None, max_seq_len=None, sent_delimiter=None, char_level=False, hard_constraint=False, transform=None, tagging_scheme='BMES', crf=False, token_key='token', dict_force: Union[hanlp_trie.dictionary.DictInterface, Dict[str, Any], Set[str]] = None, dict_combine: Union[hanlp_trie.dictionary.DictInterface, Dict[str, Any], Set[str]] = None, **kwargs)[source]

Tokenization which casts a chunking problem into a tagging problem. This task has to create batch of tokens containing both [CLS] and [SEP] since it’s usually the first task and later tasks might need them.

Parameters
  • trn – Path to training set.

  • dev – Path to dev set.

  • tst – Path to test set.

  • sampler_builder – A builder which builds a sampler.

  • dependencies – Its dependencies on other tasks.

  • scalar_mix – A builder which builds a ScalarMixWithDropout object.

  • use_raw_hidden_states – Whether to use raw hidden states from transformer without any pooling.

  • lr – Learning rate for this task.

  • separate_optimizer – Use customized separate optimizer for this task.

  • cls_is_bosTrue to treat the first token as BOS.

  • sep_is_eosTrue to treat the last token as EOS.

  • delimiter – Delimiter used to split a line in the corpus.

  • max_seq_len – Sentences longer than max_seq_len will be split into shorter ones if possible.

  • sent_delimiter – Delimiter between sentences, like period or comma, which indicates a long sentence can be split here.

  • char_level – Whether the sequence length is measured at char level.

  • hard_constraint – Whether to enforce hard length constraint on sentences. If there is no sent_delimiter in a sentence, it will be split at a token anyway.

  • transform – An optional transform to be applied to samples. Usually a character normalization transform is passed in.

  • tagging_scheme – Either BMES or BI.

  • crfTrue to enable CRF (Lafferty et al. 2001).

  • token_key – The key to tokens in dataset. This should always be set to token in MTL.

  • **kwargs – Not used.

build_criterion(model=None, **kwargs)[source]

Implement this method to build criterion (loss function).

Parameters

**kwargs – The subclass decides the method signature.

build_dataloader(data, transform: hanlp.common.transform.TransformList = None, training=False, device=None, logger: logging.Logger = None, cache=False, gradient_accumulation=1, **kwargs) → torch.utils.data.dataloader.DataLoader[source]

Build a dataloader for training or evaluation.

Parameters
  • data – Either a path or a list of samples.

  • transform – The transform from MTL, which is usually [TransformerSequenceTokenizer, FieldLength(‘token’)]

  • training – Whether this method is called on training set.

  • device – The device dataloader is intended to work with.

  • logger – Logger for printing message indicating progress.

  • cache – Whether the dataloader should be cached.

  • gradient_accumulation – Gradient accumulation to be passed to sampler builder.

  • **kwargs – Additional experimental arguments.

build_metric(**kwargs)[source]

Implement this to build metric(s).

Parameters

**kwargs – The subclass decides the method signature.

build_model(encoder_size, training=True, **kwargs) → torch.nn.modules.module.Module[source]

Build model.

Parameters
  • trainingTrue if called during training.

  • **kwargs**self.config.

build_samples(inputs, cls_is_bos=False, sep_is_eos=False)[source]

Build samples for this task. Called when this task is the first task. Default behaviour is to take inputs as list of tokens and put these tokens into a dict per sample.

Parameters
  • inputs – Inputs from users, usually a list of lists of tokens.

  • cls_is_bos – Insert BOS to the head of each sentence.

  • sep_is_eos – Append EOS to the tail of each sentence.

Returns

List of samples.

build_tokenizer(tokenizer: hanlp.transform.transformer_tokenizer.TransformerSequenceTokenizer)[source]

Build a transformer tokenizer for this task.

Parameters

tokenizer – A tokenizer which is shared but can be adjusted to provide per-task settings.

Returns

A TransformerSequenceTokenizer.

property dict_combine

The low priority dictionary which perform longest-prefix-matching on model predictions and combing them.

Examples

>>> tok.dict_combine = {'和服', '服务行业'}
>>> tok("商品和服务行业") # '和服' is not in the original results ['商品', '和', '服务']. '服务', '行业' are combined to '服务行业'
    ['商品', '和', '服务行业']
property dict_force

The high priority dictionary which perform longest-prefix-matching on inputs to split them into two subsets:

  1. spans containing no keywords, which are then fed into tokenizer for further tokenization.

  2. keywords, which will be outputed without furthur tokenization.

Caution

Longest-prefix-matching NEVER guarantee the presence of any keywords. Abuse of dict_force can lead to low quality results. For more details, refer to this book.

Examples

>>> tok.dict_force = {'和服', '服务行业'} # Force '和服' and '服务行业' by longest-prefix-matching
>>> tok("商品和服务行业")
    ['商品', '和服', '务行业']
>>> tok.dict_force = {'和服务': ['和', '服务']} # Force '和服务' to be tokenized as ['和', '服务']
>>> tok("商品和服务行业")
    ['商品', '和', '服务', '行业']
input_is_flat(data)bool[source]

Check whether the data is flat (meaning that it’s only a single sample, not even batched).

Returns

True to indicate the input data is flat.

Return type

bool

transform_batch(batch: Dict[str, Any], results: Dict[str, Any] = None, cls_is_bos=False, sep_is_eos=False) → Dict[str, Any][source]

This method is overrode to honor the zero indexed token used in custom dict. Although for a tokenizer, cls_is_bos = sep_is_eos = True, its tokens don’t contain [CLS] or [SEP]. This behaviour is adopted from the early versions and it is better kept to avoid migration efforts.

Parameters
  • batch – A batch of samples.

  • results – Predicted results from other tasks which might be useful for this task to utilize. Say a dep task uses both token and pos as features, then it will need both tok and pos results to make a batch.

  • cls_is_bos – First token in this batch is BOS.

  • sep_is_eos – Last token in this batch is EOS.

Returns

A batch.