Class: Factbase::IndexedLt

Inherits:
Object
  • Object
show all
Defined in:
lib/factbase/indexed/indexed_lt.rb

Overview

Indexed term ‘lt’.

Instance Method Summary collapse

Constructor Details

#initialize(term, idx) ⇒ IndexedLt 



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# File 'lib/factbase/indexed/indexed_lt.rb', line 8

def initialize(term, idx)
  @term = term
  @idx = idx
end

Instance Method Details

#predict(maps, _fb, params) ⇒ Object 



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# File 'lib/factbase/indexed/indexed_lt.rb', line 13

def predict(maps, _fb, params)
  return nil if @idx.nil?
  return unless @term.operands.first.is_a?(Symbol) && _scalar?(@term.operands[1])
  prop = @term.operands.first.to_s
  cache_key = [maps.object_id, @term.operands.first, :sorted]
  entry = @idx[cache_key]
  maps_array = maps.to_a
  if entry.nil?
    entry = { sorted: [], indexed_count: 0 }
    @idx[cache_key] = entry
  end
  if entry[:indexed_count] < maps_array.size
    new_pairs = []
    maps_array[entry[:indexed_count]..].each do |m|
      values = m[prop]
      next if values.nil?
      values.each do |v|
        new_pairs << [v, m]
      end
    end
    unless new_pairs.empty?
      entry[:sorted].concat(new_pairs)
      entry[:sorted].sort_by! { |pair| pair[0] }
    end
    entry[:indexed_count] = maps_array.size
  end

  threshold = @term.operands[1].is_a?(Symbol) ? params[@term.operands[1].to_s]&.first : @term.operands[1]
  return nil if threshold.nil?
  i = entry[:sorted].bsearch_index { |pair| pair[0] >= threshold } || entry[:sorted].size
  result = entry[:sorted][0...i].map { |pair| pair[1] }.uniq
  (maps & []) | result
end