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Contents
module Query
# Calculates weights for certain combinations.
#
class Weights
#
#
def initialize weights = {}
@weights_cache = {}
@weights = prepare weights
end
# Get the category indexes for the given bonuses.
#
def prepare weights
weights
end
# Get the weight of an allocation.
#
def weight_for clustered
@weights[clustered] || 0
end
# Returns an energy term E for allocation. this turns into a probability
# by P(allocation) = 1/Z * exp (-1/T * E(allocation)),
# where Z is the normalizing partition function
# sum_allocations exp(-1/T *E(allocation)), and T is a temperature constant.
# If T is high the distribution will be close to equally distributed.
# If T is low, the distribution will be the indicator function
# for min (E(allocation))…
#
# ...
#
# Just kidding. It's far more complicated than that. Ha ha ha ha ;)
#
include Helpers::Cache
def score combinations
# TODO Rewrite to use the category
#
categories = combinations.map { |combination| combination.bundle.category }.clustered_uniq
# Note: Caching will not be necessary anymore if the
# mapping is not necessary anymore.
#
cached @weights_cache, categories do
categories.map! &:name
weight_for categories
end
end
end
end
Version data entries
17 entries across 17 versions & 1 rubygems