Class: Factbase::IndexedAnd

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

Overview

Indexed term ‘and’.

Instance Method Summary collapse

Constructor Details

#initialize(term, idx) ⇒ IndexedAnd

Returns a new instance of IndexedAnd.



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

def predict(maps, fb, params)
  return if @idx.nil?
  key = [maps.object_id, @term.operands.first, @term.op]
  r = nil
  if @term.operands.all? { |o| o.op == :eq } && @term.operands.size > 1 \
    && @term.operands.all? { |o| o.operands.first.is_a?(Symbol) && _scalar?(o.operands[1]) }
    props = @term.operands.map { |o| o.operands.first }.sort!
    key = [maps.object_id, props, :multi_and_eq]
    entry = @idx[key]
    maps_array = maps.to_a
    if entry.nil?
      entry = { index: {}, indexed_count: 0 }
      @idx[key] = entry
    end
    if entry[:indexed_count] < maps_array.size
      maps_array[entry[:indexed_count]..].each do |m|
        _all_tuples(m, props).each do |t|
          entry[:index][t] ||= []
          entry[:index][t] << m
        end
      end
      entry[:indexed_count] = maps_array.size
    end
    tuples = Enumerator.product(
      *@term.operands.sort_by { |o| o.operands.first }.map do |o|
        if o.operands[1].is_a?(Symbol)
          params[o.operands[1].to_s] || []
        else
          [o.operands[1]]
        end
      end
    )
    j = tuples.flat_map { |t| entry[:index][t] || [] }.uniq(&:object_id)
    r = maps.respond_to?(:repack) ? maps.repack(j) : j
  else
    fail = false
    @term.operands.each do |o|
      n = o.predict(maps, fb, params)
      if n.nil?
        fail = true
        break
      end
      if r.nil?
        r = n
      elsif n.size < r.size * 8
        small, large = n.size < r.size ? [n.to_a, r.to_a] : [r.to_a, n.to_a]
        ids = Set.new(small.map(&:object_id))
        r = large.select { |f| ids.include?(f.object_id) }
      end
      break if r.size < maps.size / 32
      break if r.size < 128
    end
    return if fail
  end
  r
end