benchmark_results

[0, -30, 30, 0, -30, 30, 0, -30, 30, 0]
[0, -30, 30, 0, -30, 30, 0, -30, 30, 0]
[0, -30, 30, 0, -30, 30, 0, -30, 30, 0]

       user     system      total        real
eager_map  0.400000   0.010000   0.410000 (  0.413597)
lazy_map  1.640000   0.000000   1.640000 (  1.642215)
composed  0.610000   0.000000   0.610000 (  0.610857)
m_composed  0.140000   0.000000   0.140000 (  0.136136)

                             user     system      total        real
eager_map x 1            0.000000   0.000000   0.000000 (  0.000007)
eager_map x 10           0.000000   0.000000   0.000000 (  0.000007)
eager_map x 100          0.000000   0.000000   0.000000 (  0.000044)
eager_map x 1000         0.000000   0.000000   0.000000 (  0.000415)
eager_map x 10000        0.000000   0.000000   0.000000 (  0.004008)
eager_map x 100000       0.040000   0.000000   0.040000 (  0.040525)
eager_map x 1000000      0.390000   0.020000   0.410000 (  0.409117)
eager_map x 10000000     4.140000   0.100000   4.240000 (  4.242423)

                             user     system      total        real
lazy_map x 1             0.000000   0.000000   0.000000 (  0.000036)
lazy_map x 10            0.000000   0.000000   0.000000 (  0.000041)
lazy_map x 100           0.000000   0.000000   0.000000 (  0.000179)
lazy_map x 1000          0.000000   0.000000   0.000000 (  0.001815)
lazy_map x 10000         0.030000   0.010000   0.040000 (  0.033293)
lazy_map x 100000        0.170000   0.000000   0.170000 (  0.170410)
lazy_map x 1000000       1.700000   0.000000   1.700000 (  1.705107)
lazy_map x 10000000     16.890000   0.000000  16.890000 ( 16.890536)

                             user     system      total        real
composed x 1             0.000000   0.000000   0.000000 (  0.000006)
composed x 10            0.000000   0.000000   0.000000 (  0.000008)
composed x 100           0.000000   0.000000   0.000000 (  0.000061)
composed x 1000          0.000000   0.000000   0.000000 (  0.000636)
composed x 10000         0.000000   0.000000   0.000000 (  0.006038)
composed x 100000        0.060000   0.000000   0.060000 (  0.059965)
composed x 1000000       0.600000   0.000000   0.600000 (  0.601747)
composed x 10000000      6.100000   0.010000   6.110000 (  6.109109)

                             user     system      total        real
m_composed x 1           0.000000   0.000000   0.000000 (  0.000005)
m_composed x 10          0.000000   0.000000   0.000000 (  0.000004)
m_composed x 100         0.000000   0.000000   0.000000 (  0.000017)
m_composed x 1000        0.000000   0.000000   0.000000 (  0.000137)
m_composed x 10000       0.000000   0.000000   0.000000 (  0.001321)
m_composed x 100000      0.010000   0.000000   0.010000 (  0.013195)
m_composed x 1000000     0.140000   0.000000   0.140000 (  0.131730)
m_composed x 10000000    1.330000   0.030000   1.360000 (  1.360293)

func_comp_gen.rb

#!/usr/bin/env ruby

require 'benchmark'

DOUBLE = -> (i) { 2 * i }
ADD_TWO = -> (i) { 2 + i }
MOD_THREE = -> (i) { i % 3 }
TRIPLE = -> (i) { i * 3 }
TIMES_TEN = -> (i) { i * 10 }
MINUS_30 = -> (i) { i - 30 }

COMPOSED = -> (i) do
  MINUS_30.call(TIMES_TEN.call(TRIPLE.call(MOD_THREE.call(ADD_TWO.call(DOUBLE.call(i))))))
end

MANUAL_COMPOSITION = -> (i) do
  ((((((i * 2) + 2) % 3) * 3) * 10) - 30)
end

def get_enumerator count
  i = 0
  Enumerator.new do |y|
    y.yield i while count >= i += 1
  end
end

def get_array count
  get_enumerator(count).to_a
end

def get_range count
  (1..count)
end

def demo
  p eager_map(get_enumerator 10).to_a
  p composed(get_enumerator 10).to_a
  p lazy_map(get_enumerator 10).to_a
  puts
end

def eager_map items
  items.map(&DOUBLE).map(&ADD_TWO).map(&MOD_THREE).map(&TRIPLE).map(&TIMES_TEN).map(&MINUS_30)
end

def lazy_map items
  items.lazy.map(&DOUBLE).map(&ADD_TWO).map(&MOD_THREE).map(&TRIPLE).map(&TIMES_TEN).map(&MINUS_30)
end

def composed items
  items.map &COMPOSED
end

def m_composed items
  items.map &MANUAL_COMPOSITION
end

demo

strategy = :get_range

n = 1_000_000
Benchmark.bm do |x|
  x.report('eager_map') { eager_map(send(strategy, n)).count }
  x.report('lazy_map') { lazy_map(send(strategy, n)).count }
  x.report('composed') { composed(send(strategy, n)).count }
  x.report('m_composed') { m_composed(send(strategy, n)).count }
end


[:eager_map, :lazy_map, :composed, :m_composed].each do |method|
  puts

  Benchmark.bm(22) do |x|
    (0..7).each do |e|
      x.report("#{method} x #{10 ** e}") { self.send(method, send(strategy, 10 ** e)).count }
    end
  end
end