abscondment

(use '(incanter core charts io latex))

(defn stirling [#^Integer n]
  (* (Math/sqrt (* 2 n Math/PI))
     (Math/pow n n)
     (Math/pow Math/E (* -1 n))))

(defn fact [#^Integer n]
  (reduce * (range 2 (inc n))))

abscondment

class OptionalSessionStore < SqlSessionStore

  cattr_accessor :enabled_session_class  
  cattr_accessor :disabled

  class << self
    def disabled=(v)
      if self.disabled != v
        @@disabled = v
        self.toggle_session_class

abscondment

  before_filter :toggle_session

  def toggle_session    
    # Disable the session if we spy a bot (or it was
    # disabled elsewhere), enable otherwise.
    if @disable_session.nil?
      @disable_session = UrbanspoonUtil.is_megatron?(request.user_agent)
    end
    OptionalSessionStore.disabled = @disable_session
  end

abscondment

# NoSession acts like a session, but doesn't get stored anywhere. Sneaky.
class NoSession < AbstractSession
  class << self
    def find_session(session_id); end
    def create_session(session_id, data={})
      new(session_id, data)
    end
    def delete_all(condition=nil); end
  end

abscondment

10.times do
  r = Restaurant.find(:all, :conditions => ['id IN (?)', ids])
  Restaurant.add_cuisines(r)
  r.map(&:cuisines).flatten.map(&:id)
end

# benchmarked 10 times
    user     system      total        real
3.070000   0.040000   3.110000 (  3.148139)
3.040000   0.030000   3.070000 (  3.133394)

abscondment

def Restaurant.add_cuisines(restaurants)
  return [] if restaurants.empty?
  
  ids = []
  id_map = {}
  restaurants.each do |r|
    id_map[r[:id]] = r
    ids << r[:id]
    # make sure ActiveRecord won't try to load cuisines again
    r.cuisines.loaded

abscondment

r.map(&:cuisines).flatten.map(&:object_id).uniq.length
 => 2001
r.map(&:cuisines).flatten.map(&:id).uniq.length
 => 73

abscondment

10.times do
  r = Restaurant.find(:all, :include => [:cuisines], :conditions => ['id IN (?)', ids])
  r.map(&:cuisines).flatten.map(&:id)
end

 # benchmarked 10 times
    user     system      total        real
5.540000   0.010000   5.550000 (  5.553716)
5.560000   0.000000   5.560000 (  5.566566)
5.670000   0.010000   5.680000 (  5.687871)

abscondment

10.times do
  r = Restaurant.find(:all, :conditions => ['id IN (?)', ids])
  r.map(&:cuisines).flatten.map(&:id)
end

# benchmarked 10 times
     user     system      total        real
10.170000   0.470000  10.640000 ( 11.809886)
 9.630000   0.410000  10.040000 ( 11.076710)
11.220000   0.520000  11.740000 ( 12.819519)

abscondment

class Restaurant < ActiveRecord::Base
  has_many :restaurant_cuisines, :dependent => :delete_all
  has_many :cuisines, :through => :restaurant_cuisines
end

class Cuisine < ActiveRecord::Base
  has_many :restaurant_cuisines, :dependent => :delete_all
  has_many :restaurants, :through => :restaurant_cuisines
end