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Contents
module Picky
module Generators
module Weights
# Uses a logarithmic weight.
#
# If given a constant, this will be added to the weight.
#
# If for a key k we have x ids, the weight is:
# w(x): log(x)
# Special case: If x < 1, then we use 0.
#
class Logarithmic < Strategy
def initialize constant = 0.0
@constant = constant
# # Note: Optimisation since it is called
# # once per indexed object.
# #
# if constant == 0.0
# install_without_constant
# else
# @constant = constant
# install_with_constant
# end
end
def weight_for amount
return @constant if amount < 1
@constant + Math.log(amount).round(3)
end
# def install_with_constant
# # Sets the weight value.
# #
# # If the size is 0 or one, we would get -Infinity or 0.0.
# # Thus we do not set a value if there is just one. The default, dynamically, is 0.
# #
# # BUT: We need the value, even if 0. To designate that there IS a weight!
# #
# def weight_for amount
# return @constant if amount < 1
# @constant + Math.log(amount).round(3)
# end
# end
# def install_without_constant
# def weight_for amount
# return 0 if amount < 1
# Math.log(amount).round 3
# end
# end
end
end
end
end
Version data entries
78 entries across 78 versions & 1 rubygems