Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-13 Thread Colin Law
On 12 March 2011 23:29, Conrad Taylor conra...@gmail.com wrote: On Sat, Mar 12, 2011 at 1:07 PM, Colin Law clan...@googlemail.com wrote: On 12 March 2011 20:47, Michael Pavling pavl...@gmail.com wrote: On 12 March 2011 14:23, Colin Law clan...@googlemail.com wrote: On 12 March 2011 13:42,

[Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Erwin
I know how to generate a random number between 1 and 2 : def random return (1 + rand(2)) end but let's say I would like to return 1 in 80% of the calls and 2 in 20% of the call... which library should I use ? ( I've seen a lot at http://raa.ruby-lang.org/ ) thanks for your suggestions --

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Colin Law
On 12 March 2011 10:10, Erwin yves_duf...@mac.com wrote: I know how to generate a random number between 1 and 2 : def random  return (1 + rand(2)) end but let's say  I would like to return 1 in 80% of the calls and 2 in 20% of the call... which library should I use ?  ( I've seen a lot at

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Rob Biedenharn
On Mar 12, 2011, at 5:37 AM, Colin Law wrote: On 12 March 2011 10:10, Erwin yves_duf...@mac.com wrote: I know how to generate a random number between 1 and 2 : def random return (1 + rand(2)) end but let's say I would like to return 1 in 80% of the calls and 2 in 20% of the call... which

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Colin Law
On 12 March 2011 13:42, Rob Biedenharn r...@agileconsultingllc.com wrote: On Mar 12, 2011, at 5:37 AM, Colin Law wrote: On 12 March 2011 10:10, Erwin yves_duf...@mac.com wrote: I know how to generate a random number between 1 and 2 : def random  return (1 + rand(2)) No it doesn't

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Michael Pavling
On 12 March 2011 14:23, Colin Law clan...@googlemail.com wrote: On 12 March 2011 13:42, Rob Biedenharn r...@agileconsultingllc.com wrote: def usually_one  rand 0.80 ? 1 : 2 end Yes, much better.  I suppose it is the old programmer in me instinctively avoiding floating point to save on

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Michael Pavling
On 12 March 2011 20:47, Michael Pavling pavl...@gmail.com wrote:  def usually_one    [1,2,2,2,2][rand(5)]  end *ahem* of course.. this is the total opposite of what the OP asked for, and returns 1 in 20% of the calls :-D sorry for not paying attention oops! -- You received this message

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Colin Law
On 12 March 2011 20:47, Michael Pavling pavl...@gmail.com wrote: On 12 March 2011 14:23, Colin Law clan...@googlemail.com wrote: On 12 March 2011 13:42, Rob Biedenharn r...@agileconsultingllc.com wrote: def usually_one  rand 0.80 ? 1 : 2 end Yes, much better.  I suppose it is the old

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Michael Pavling
On 12 March 2011 21:07, Colin Law clan...@googlemail.com wrote: Ha!  Vindicated I expected to get different times, but to keep the proportions the same... but I get a little difference in order of speed: begin ? t=Time.now 100.times{(rand(100) + 120)/100} puts Time.now-t end 1.200484

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Colin Law
On 12 March 2011 21:36, Michael Pavling pavl...@gmail.com wrote: On 12 March 2011 21:07, Colin Law clan...@googlemail.com wrote: Ha!  Vindicated I expected to get different times, but to keep the proportions the same... but I get a little difference in order of speed: begin ? t=Time.now

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Michael Pavling
On 12 March 2011 22:01, Colin Law clan...@googlemail.com wrote: OK, I admit defeat.  the benefit of your technique is even greater on 1.8.7, taking only 0.67 secs on my machine. Nah! Who cares if it takes half-a-second or a second to select a million random numbers any of the methods are

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Colin Law
On 12 March 2011 22:16, Michael Pavling pavl...@gmail.com wrote: On 12 March 2011 22:01, Colin Law clan...@googlemail.com wrote: OK, I admit defeat.  the benefit of your technique is even greater on 1.8.7, taking only 0.67 secs on my machine. Nah! Who cares if it takes half-a-second or a

Re: [Rails] [RUBY] how do generate a random number w specific distribution ( which library ?)

2011-03-12 Thread Conrad Taylor
On Sat, Mar 12, 2011 at 1:07 PM, Colin Law clan...@googlemail.com wrote: On 12 March 2011 20:47, Michael Pavling pavl...@gmail.com wrote: On 12 March 2011 14:23, Colin Law clan...@googlemail.com wrote: On 12 March 2011 13:42, Rob Biedenharn r...@agileconsultingllc.com wrote: def