Benchmark Array#product

benchmark_array_product.rb

require 'benchmark'

def test_nested_loop
  1.upto(20) do |x|
    1.upto(30) do |y|
      x * y
    end
  end
end

def test_array_product
  (1..20).to_a.product((1..30).to_a) do |x, y|
    x * y
  end
end

n = 10_000
Benchmark.bmbm(15) do |x|
  x.report("nested loop")   { n.times { test_nested_loop } }
  x.report("Array#product") { n.times { test_array_product } }
end

# >> 
# >>                       user     system      total        real
# >> nested loop       0.209984   0.000150   0.210134 (  0.210229)
# >> Array#product     0.458375   0.000405   0.458780 (  0.459150)