Module: BenchmarkHarness::Stats

Included in:
Array
Defined in:
lib/benchmark_harness/stats.rb

Overview

copied from github.com/mgrigajtis/easystats/blob/master/lib/easystats.rb until orig author fixes sum conflict problem

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

take in an array of numbers and calculate the sum



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# File 'lib/benchmark_harness/stats.rb', line 6

def self.included(base)
  unless  base.method_defined? :sum
    base.class_eval do
      define_method :sum do
        data = self
        sum_of_numbers = 0

        # Get the total sum only if there are actually numbers to total
        if data.count > 0
          data.each do |num|
            sum_of_numbers += num
          end
        else
          sum_of_numbers = 0
        end

        sum_of_numbers
      end
    end
  end      
end

Instance Method Details

#mean ⇒ Object Also known as: average

take in an array of numbers and calculate the mean (average)



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# File 'lib/benchmark_harness/stats.rb', line 29

def mean
  data = self

  # Check to make sure there are numbers to avoid division by 0
  if data.count > 0
    self.sum / data.count.to_f
  else
    0
  end
end

#median ⇒ Object

take in the array of numbers and calculate the median



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# File 'lib/benchmark_harness/stats.rb', line 86

def median
  data = self

  halfway = data.count / 2

  # Sort the array
  data = data.sort

  # The median will be different based on the number of numbers in the array
  # If there is an even number in the array
  if(data.count % 2) == 0
    median = (data[halfway] + data[halfway-1]) / 2.0

  # Else, there is an odd number of elements in the array
  else
    median = data[halfway]
  end

  median
end

#mode ⇒ Object

take in an array of numbers and return the mode



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# File 'lib/benchmark_harness/stats.rb', line 115

def mode
  data = self

  # Sort the array
  data = data.sort

  # create a flag to tell the user if all the numbers only appear once
  no_mode = true

  # The variable that will hold the highest number
  highest_value = 0

  # The variable that holds the most time the value appears
  most_times = 0

  # Create a new hash to hold the numbers
  tmp = Hash.new

  # Populate the hash
  data.each do |num|
    if tmp["#{num}"].nil? == false
      tmp["#{num}"] = tmp["#{num}"].to_i + 1
    else
      tmp["#{num}"] = 1
    end
  end

  # Check to make sure that there is a mode
  data.each do |num|
    if tmp["#{num}"].to_i > 1
      no_mode = false
    end
  end

  if no_mode == true
    0
  else
    data.each do |num|
      if tmp["#{num}"].to_i > most_times
        highest_value = num
        most_times = tmp["#{num}"]
      end 
    end

    # now loop through again just to make sure another number doesn't appear an equal number of times
    data.each do |num|
      if num != highest_value
        if tmp["#{num}"].to_i == most_times
          no_mode = true
        end
      end
    end

    if no_mode == true
      0
    else
      highest_value
    end
  end
end

#range ⇒ Object

take in an array of numbers and calculate the range



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# File 'lib/benchmark_harness/stats.rb', line 108

def range
  data = self
  data = data.sort
  data[data.count-1] - data[0]
end

#standard_deviation ⇒ Object

take in an array of numbers and calculate the standard deviation



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# File 'lib/benchmark_harness/stats.rb', line 62

def standard_deviation
  data = self
  sum_of_deviations_squared = self.sum_of_deviations_squared

  if data.count > 1 
    Math::sqrt(sum_of_deviations_squared / (data.count-1))
  else
    0
  end
end

#sum_of_deviations_squared ⇒ Object

this is an internat function (technically the developer can use it but should have no need) this function returns the sum of each squared difference of mean



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# File 'lib/benchmark_harness/stats.rb', line 43

def sum_of_deviations_squared
  data = self

  deviations = Array.new
  average = self.mean
  sum_of_deviations_squared = 0

  data.each do |num|
    deviations.push((num-average)**2)
  end

  deviations.each do |num|
    sum_of_deviations_squared += num
  end

  sum_of_deviations_squared
end

#variance ⇒ Object 



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# File 'lib/benchmark_harness/stats.rb', line 73

def variance
  data = self
  average = self.mean
  sum_of_deviations = self.sum_of_deviations_squared

  if data.count > 0
    sum_of_deviations / data.count.to_f
  else
    0
  end
end