3 ms·

Honestly, my guess is that you were doing something wrong in the Go code. Go is definitely faster than Ruby, even on a single core machine. http://benchmarksga

• pkulak 14y ago
  EDIT: haha, thanks so much, guys! Stupid mistake. Go is _significantly_ faster if written properly. I'd love to know what I screwed up. The results surprised me: https://gist.github.com/pkulak/99d2d5a5968b5fc03754 https://gist.github.com/pkulak/99d2d5a5968b5fc03754 https://gist.github.com/pkulak/909d882614e0781e4525 https://gist.github.com/pkulak/909d882614e0781e4525 bender:Desktop phil$ time go run primes.go Found them! 78702 real 0m21.349s user 0m21.304s sys 0m0.033s bender:Desktop phil$ ruby -v ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11.4.0] bender:Desktop phil$ time ruby primes.rb Found them! 78702 real 0m7.656s user 0m7.651s sys 0m0.005s bender:Desktop phil$ time go build primes.go real 0m0.269s user 0m0.231s sys 0m0.033s
  • hndc 14y ago
    You're using integer arithmetic in Ruby and floating-point arithmetic in Go. Try replacing math.Mod(float64(i), float64(j)) with i%j My results: $ time go run primes.go Found them! 78702 real 0m0.835s user 0m0.787s sys 0m0.039s $ time ruby primes.rb Found them! 78702 real 0m21.013s user 0m21.005s sys 0m0.016s
    • agentS 14y ago
      It's worth noting that the time on the go side includes the time to run the compiler, and linker, since you're using `go run`, instead of `go build`. Not saying that's bad, just something to keep in mind when benchmark numbers are in the second range. (I understand that you did because the original poster did it)
  • dmit 14y ago
    You should use the same integer remainder operator (%) as in the Ruby version instead of math.Mod(float64(i), float64(j)): <...> for j := 2; j < limit; j++ { if i % j == 0 { found = true <...>