Class: Conductor::Weights

Inherits:
Object
  • Object
show all
Defined in:
lib/conductor/weights.rb

Class Method Summary collapse

Class Method Details

.compute(group_name, alternatives) ⇒ Object

Computes the weights for a group based on the attribute for weighting and activity for the last two weeks.

If no conversions have taken place yet for a group, all alternatives are weighted equally.

TODO: add notification table and all notification if there are no conversions and we are out of the equalization period



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# File 'lib/conductor/weights.rb', line 34

def compute(group_name, alternatives)
  # create the conditions after sanitizing sql.
  alternative_filter = alternatives.inject([]) {|res,x| res << "alternative = '#{Conductor.sanitize(x)}'"}.join(' OR ')

  # pull daily data and recompute if daily data
  group_rows = Conductor::Experiment::Daily.since(14.days.ago).for_group(group_name).find(:all, :conditions => alternative_filter)

  unless group_rows.empty?
    Conductor::Experiment::Weight.delete_all(:group_name => group_name) # => remove all old data for group
    total = group_rows.sum_it(Conductor.attribute_for_weighting)
    data = total > 0 ? compute_weights_for_group(group_name, group_rows, total) : assign_equal_weights(group_rows)
    update_weights_in_db(group_name, data)
  end
end

.find_or_create(group_name, alternatives) ⇒ Object

Returns all the weights for a given group. In the event that the alternatives specified for the group do not match all the alternatives previously computed for the group, new weights are generated. The cache is used to speed up this check



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# File 'lib/conductor/weights.rb', line 8

def find_or_create(group_name, alternatives)
  weights_for_group = Conductor.cache.read("Conductor::Experiment::#{Conductor.attribute_for_weighting}::#{group_name}::Alternatives")

  alternatives_array = weights_for_group.map(&:alternative).sort if weights_for_group
  if alternatives_array.eql?(alternatives.sort)
    Conductor.log('alternatives equal to cache')
    return weights_for_group
  else
    # Conductor.log('alternatives NOT equal to cache.  Need to recompute')
    compute(group_name, alternatives)

    # get the new weights
    weights_for_group = Conductor::Experiment::Weight.find(:all, :conditions => "group_name = '#{group_name}'")
    Conductor.cache.delete("Conductor::Experiment::#{Conductor.attribute_for_weighting}::#{group_name}::Alternatives")
    Conductor.cache.write("Conductor::Experiment::#{Conductor.attribute_for_weighting}::#{group_name}::Alternatives", weights_for_group)
    return weights_for_group
  end
end