Some naive bigdecimal comparison

BigDecimal

require 'bigdecimal'
require 'benchmark'

n = 100_000
Benchmark.bm do |x|
  x.report("float") { n.times{ 15.0 / 13.2; 15.0 * 13.2; 15.0 - 13.2; 15.0 + 13.2 } }
  x.report("bd on the fly") do 
    n.times do 
      BigDecimal.new("15.0") / BigDecimal.new("13.2")
      BigDecimal.new("15.0") * BigDecimal.new("13.2")
      BigDecimal.new("15.0") - BigDecimal.new("13.2")
      BigDecimal.new("15.0") + BigDecimal.new("13.2")
    end
  end
  x.report("bd cached objs") do 
    n.times do 
      fift = BigDecimal.new("15.0")
      thirt = BigDecimal.new("13.2")

      fift / thirt
      fift * thirt
      fift - thirt
      fift + thirt
    end
  end
end

###################################################
                  user     system      total        real
float           0.010000   0.000000   0.010000 (  0.016775)
bd on the fly   0.680000   0.000000   0.680000 (  0.676219)
bd cached objs  0.360000   0.000000   0.360000 (  0.361639)