From: Florian Frank <flori@...>
Date: 2005-06-22T05:40:14+09:00
Subject: Re: 1. Ruby result:  101 seconds , 2. Java result:9.8 seconds, 3. Perl result:62 seconds

Michael Tan wrote:

>Just new to Ruby since last week, running  my same functional program on the windows XP(Pentium M1.5G), the Ruby version is 10 times slower than the Java version. The program is to find the prime numbers like 2, 3,5, 7, 11, 13...  Are there setup issues? or it is normal?
>  
>
Your programs aren't the same. The Java and Perl program don't use 
objects, the Ruby version does. Both the Perl and the Java version could 
overflow, if numbers get too big, the Ruby program doesn't suffer from this.

And look, I just made the Ruby version, faster, smaller and more object 
oriented:

class Integer
  def prime?
    not (2..Math.sqrt(self).floor).find { |i| self % i == 0 }
  end
end
######### star here:How many primes in 2 to  50000?
start_number, max_number = 2, 50000
time  = Time.now.to_f
total = (start_number..max_number).inject(0) { |s,i| s + (i.prime? ? 1 : 
0) }
time  = Time.now.to_f - time
puts "There are #{total} primes between #{start_number} and #{max_number}"
puts "Time taken %.3f seconds" % time

Now do the same in the other two languages...

-- 
Florian Frank