Class: NerRuby::Decoder

Inherits:
Object
  • Object
show all
Defined in:
lib/ner_ruby/decoder.rb

Constant Summary collapse

LABEL_MAPS = 
{
  "bert-base-NER" => {
    0 => "O",
    1 => "B-MISC",
    2 => "I-MISC",
    3 => "B-PER",
    4 => "I-PER",
    5 => "B-ORG",
    6 => "I-ORG",
    7 => "B-LOC",
    8 => "I-LOC"
  }
}.freeze

Instance Method Summary collapse

Constructor Details

#initialize(label_map: nil) ⇒ Decoder

Returns a new instance of Decoder.



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# File 'lib/ner_ruby/decoder.rb', line 19

def initialize(label_map: nil)
  @label_map = label_map || LABEL_MAPS["bert-base-NER"]
end

Instance Method Details

#decode(tokens, predictions, scores: nil, original_text: nil) ⇒ Object 



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# File 'lib/ner_ruby/decoder.rb', line 23

def decode(tokens, predictions, scores: nil, original_text: nil)
  entities = []
  current_entity = nil

  tokens.each_with_index do |token, i|
    next if special_token?(token)

    label = @label_map[predictions[i]] || "O"
    score = scores ? scores[i] : 1.0

    if label.start_with?("B-")
      entities << build_entity(current_entity, original_text) if current_entity
      entity_type = label.sub("B-", "")
      current_entity = { raw_tokens: [token], label: entity_type, scores: [score] }
    elsif label.start_with?("I-") && current_entity
      entity_type = label.sub("I-", "")
      if entity_type == current_entity[:label]
        current_entity[:raw_tokens] << token
        current_entity[:scores] << score
      else
        entities << build_entity(current_entity, original_text)
        current_entity = nil
      end
    else
      entities << build_entity(current_entity, original_text) if current_entity
      current_entity = nil
    end
  end

  entities << build_entity(current_entity, original_text) if current_entity
  entities
end