Benchmark Rational vs. BigDecimal

float_alternatives.rb

require 'benchmark/ips'
require 'bigdecimal'

Benchmark.ips do |x|
  x.report('Rational from String') { '214.04'.to_r - '74.79'.to_r + '74.79'.to_r > '214.04'.to_r }

  x.report('Rational from Float') { 214.04.to_r - 74.79.to_r + 74.79.to_r > 214.04.to_r }


  x.report('BigDecimal from String') { BigDecimal.new('214.04') - BigDecimal.new('74.79') + BigDecimal.new('74.79') > BigDecimal.new('214.04') }

  x.report('BigDecimal from Float (precision auto)') { BigDecimal.new(214.04, 0) - BigDecimal.new(74.79, 0) + BigDecimal.new(74.79, 0) > BigDecimal.new(214.04, 0) }

  x.report('BigDecimal from Float (precision 12)') { BigDecimal.new(214.04, 12) - BigDecimal.new(74.79, 12) + BigDecimal.new(74.79, 12) > BigDecimal.new(214.04, 12) }

  x.compare!
end

=begin
Comparison:
Rational from Float:   414019.6 i/s
BigDecimal from String:   321991.7 i/s - 1.29x slower
Rational from String:   207141.2 i/s - 2.00x slower
BigDecimal from Float (precision 12):    90158.5 i/s - 4.59x slower
BigDecimal from Float (precision auto):    89520.5 i/s - 4.62x slower
=end


Benchmark.ips do |x|
  x.report('BigDecimal from String comparison') { BigDecimal.new('0.161738278059140662') > BigDecimal.new('0.161738278059140663') }

  x.report('BigDecimal from Float comparison') { BigDecimal.new(0.161738278059140662, 0) > BigDecimal.new(0.161738278059140663, 0) }


  x.report('Rational from String comparison') { '0.161738278059140662'.to_r > '0.161738278059140663'.to_r }

  x.report('Rational from Float comparison') { 0.161738278059140662.to_r > 0.161738278059140663.to_r }


  x.report('Mixed comparison') { '0.161738278059140662'.to_r > BigDecimal.new('0.161738278059140663') }


  x.compare!
end

=begin
Comparison:
Rational from Float comparison:   813176.0 i/s
BigDecimal from String comparison:   709671.6 i/s - 1.15x slower
Rational from String comparison:   327161.3 i/s - 2.49x slower
Mixed comparison:   231617.9 i/s - 3.51x slower
BigDecimal from Float comparison:   189118.7 i/s - 4.30x slower

=end


Benchmark.ips do |x|
  rate_rational = '0.161738278059140662'.to_r
  rate_bigdecimal = BigDecimal.new('0.161738278059140662')

  x.report('Pre-parsed Rational vs. BigDecimal') { rate_rational > BigDecimal.new('0.161738278059140663') }
  x.report('Pre-parsed Rational vs. Rational') { rate_rational > '0.161738278059140663'.to_r }


  x.report('Pre-parsed BigDecimal vs. BigDecimal') { rate_bigdecimal > BigDecimal.new('0.161738278059140663') }
  x.report('Pre-parsed BigDecimal vs. Rational') { rate_bigdecimal > '0.161738278059140663'.to_r }


  x.compare!
end

=begin
Comparison:
Pre-parsed BigDecimal vs. BigDecimal:  1332389.2 i/s
Pre-parsed Rational vs. Rational:   565026.2 i/s - 2.36x slower
Pre-parsed Rational vs. BigDecimal:   354856.6 i/s - 3.75x slower
Pre-parsed BigDecimal vs. Rational:   314632.9 i/s - 4.23x slower
=end