Class: Informers::SentimentAnalysis

Inherits:
Object
  • Object
show all
Defined in:
lib/informers/sentiment_analysis.rb

Instance Method Summary collapse

Constructor Details

#initialize(model_path) ⇒ SentimentAnalysis

Returns a new instance of SentimentAnalysis.



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# File 'lib/informers/sentiment_analysis.rb', line 18

def initialize(model_path)
  tokenizer_path = File.expand_path("../../vendor/bert_base_tok.bin", __dir__)
  @tokenizer = BlingFire.load_model(tokenizer_path)
  @model = OnnxRuntime::Model.new(model_path)
end

Instance Method Details

#predict(texts) ⇒ Object 



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# File 'lib/informers/sentiment_analysis.rb', line 24

def predict(texts)
  singular = !texts.is_a?(Array)
  texts = [texts] if singular

  # tokenize
  input_ids =
    texts.map do |text|
      tokens = @tokenizer.text_to_ids(text, nil, 100) # unk token
      tokens.unshift(101) # cls token
      tokens << 102 # sep token
      tokens
    end

  max_tokens = input_ids.map(&:size).max
  attention_mask = []
  input_ids.each do |ids|
    zeros = [0] * (max_tokens - ids.size)

    mask = ([1] * ids.size) + zeros
    attention_mask << mask

    ids.concat(zeros)
  end

  # infer
  input = {
    input_ids: input_ids,
    attention_mask: attention_mask
  }
  output = @model.predict(input)

  # transform
  scores =
    output["output_0"].map do |row|
      mapped = row.map { |v| Math.exp(v) }
      sum = mapped.sum
      mapped.map { |v| v / sum }
    end

  labels = ["negative", "positive"]
  scores.map! do |item|
    {label: labels[item.each_with_index.max[1]], score: item.max}
  end

  singular ? scores.first : scores
end