From: khaines@...
Date: 2006-07-13T04:18:01+09:00
Subject: Re: Generating a random floating point number

On Thu, 13 Jul 2006, Mauricio Fernandez wrote:

> On Thu, Jul 13, 2006 at 12:39:50AM +0900, khaines@enigo.com wrote:
>> def fp_rand(limit)
>>   fl = limit.floor
>>   rm = limit.remainder(fl)
>>   rand(fl) + rand(rm)
>> end
>>
>>
>> fp_rand(12.73)
>> => 10.1895547681143
>
> <nitpicking>
> That method would never return values whose decimal part >= 0.73 in the above
> example.
> Besides, the variance of the resulting random variable would be lower than
> for the correct  limit * rand():
>   (fl^2 + rm^2) / 12    instead of    (fl + rm)^2 / 12 = limit^2 / 12
> </nitpicking>

Thanks, Mauricio.  It's always good to have one's nits picked on 
occasion.  :)


Kirk