Class QueryVec

libs/search/doc_vec.hpp:78–131

This class represents a search query in a vector space of tokens.

// This class represents a search query in a vector space of tokens.
class QueryVec
{
public:
  class Builder
  {
  public:
    template <typename Token>
    void AddFull(Token && token)
    {
      m_tokens.emplace_back(std::forward<Token>(token));
    }

    template <typename Token>
    void SetPrefix(Token && token)
    {
      m_prefix = std::forward<Token>(token);
    }

  private:
    friend class QueryVec;

    std::vector<strings::UniString> m_tokens;
    std::optional<strings::UniString> m_prefix;
  };

  explicit QueryVec(IdfMap & idfs) : m_idfs(&idfs) {}

  QueryVec(IdfMap & idfs, Builder const & builder);

  // Computes cosine similarity between |*this| and |rhs|.
  double Similarity(IdfMap & docIdfs, DocVec const & rhs);

  // Computes vector norm of the query.
  double Norm();

  bool Empty() const { return m_tfs.empty() && !m_prefix; }

private:
  double GetFullTokenWeight(size_t i);
  double GetPrefixTokenWeight();

  friend std::string DebugPrint(QueryVec const & qv)
  {
    std::ostringstream os;
    os << "QueryVec " + ::DebugPrint(qv.m_tfs);
    if (qv.m_prefix)
      os << " " << DebugPrint(*qv.m_prefix);
    return os.str();
  }

  IdfMap * m_idfs;
  std::vector<TokenFrequencyPair> m_tfs;
  std::optional<strings::UniString> m_prefix;
};
}  // namespace search