From: Michael Tan <mtan1232000@...>
Date: 2005-06-26T09:45:10+09:00
Subject: I saw the beauty of  Ruby Re: 1. Ruby result: 101 seconds , 2. Java result:9.8 seconds, 3. Perl result:62 seconds

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Thank you for everyone who replied my first post with my first Ruby program here directly or indirectly. It is really a great community, a lot of fun. I did not expect I could learn so much. Here are some of I learned from everyone: 1) everything is object,so all are method calls (to_i, to_f, each, ...) . 2)open class even for Integer, String... ,.3) method chain , 4) .yield and code block and more. And especially I have to thank the following people: 


Florian Frank : not , enum, .floor .find, inject(0)...

Ken Kunz: how to use "benchmark" , .step ,easy to understand...

Ara.T.Howard: how to write a benchmark, fork, subprocess, lambda(Proc), label ,Inline C 

Josef 'Jupp' SCHUGT: best algorithm so far , array.push...

Ryan Davis:-rzenoptimize
Issues: 1) I installed zenhacks and RubyToC in order to run -rzenoptimize but failed. I will work on that later.

2) I installed win32-process to implement the "fork" method, failed. I will work on that later.

BTW, To prove nothing , just for fun, here is the results from the final version (from Josef 'Jupp' SCHUGT, i changed a little bit) 

My original one: 101 seconds. 

The final one: 0.48 seconds 

Perl CPAN version: 5 seconds (only means the algorithm is not good)

So if Josef put his version in RAA , the Ruby RAA "primes" will 10 times faster than the perl CPAN one for the time being. :o)

class Integer

def primes

f=2

p=[] if self <2

p=[2] if self >=2

3.step(self, 2) do |i|

r = Math.sqrt(i).to_i

p.each { |f| break if (i%f).zero? or f > r}

p.push(i) if (i%f).nonzero?

end # end the do block

return p

end

end

a=Time.now.to_f

puts 50000.primes.length

printf "time taken %.2f seconds", Time.now.to_f-a

Perl CPAN: 

use Math::Big 'primes';

my $max = 50000;

my $start = time();

my $total = primes($max);

my $time = time() - $start;

print "There are $total primes below $max.\n";

print "Time taken was $time seconds\n";

 

 

 


		
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