Class: ForgetTable::Distribution

Inherits:
Object
  • Object
show all
Defined in:
lib/forget_table/distribution.rb

Overview

Represents a categorical distribution composed by weighted bins.

A distribution is instantiated with the following parameters:

  • name: the name of the distribution

  • redis: the redis client that will host the distribution

Example of an instance:

distribution: "guitars"
  bins: "fender" => 10, "gibson" => 20, "epi" => "30

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name:, redis:) ⇒ Distribution

Returns a new instance of Distribution.



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# File 'lib/forget_table/distribution.rb', line 20

def initialize(name:, redis:)
  @name = name
  @redis = redis
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/forget_table/distribution.rb', line 18

def name
  @name
end

Instance Method Details

#distribution(number_of_bins: -1,, with_scores: false) ⇒ Object

Returns the list of bins in the distribution. Params:

  • number_of_bins

  • options



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# File 'lib/forget_table/distribution.rb', line 45

def distribution(number_of_bins: -1, with_scores: false)
  begin
    decrement!

    stop_bin = (number_of_bins == -1) ? -1 : (number_of_bins - 1)
    redis.zrevrange(name, 0, stop_bin, with_scores: with_scores)
  rescue RuntimeError
    [[]]
  end
end

#hits_count ⇒ Object 



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# File 'lib/forget_table/distribution.rb', line 67

def hits_count
  redis.get(hits_count_key).to_i
end

#increment(bin:, amount: 1) ⇒ Object

Increments the bin score by the given amount. params:

  • bin

  • amount



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# File 'lib/forget_table/distribution.rb', line 29

def increment(bin:, amount: 1)
  redis.zincrby(name, amount, bin)

  # Increment the total number of hits
  stored_bins = redis.incrby(hits_count_key, 1)

  if stored_bins == 1
    # Set the initial timestamp if never set
    redis.set(last_updated_at_key, Time.now.to_i)
  end
end

#last_updated ⇒ Object 



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# File 'lib/forget_table/distribution.rb', line 63

def last_updated
  redis.get(last_updated_at_key)
end

#score_for_bin(bin) ⇒ Object

Returns the score for the given bin



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# File 'lib/forget_table/distribution.rb', line 57

def score_for_bin(bin)
  decrement!

  redis.zscore(name, bin)
end