From: Joel VanderWerf <vjoel@...>
Date: 2009-06-19T06:01:36+09:00
Subject: Re: floating point accuracy in JRuby

Steven D. Arnold wrote:
> [ 03:23 PM (5) omega:thoth ~ ] > jirb
> irb(main):001:0> 0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1
> => 0.9999999999999999
> [ 03:33 PM (8) omega:thoth ~ ] > irb
>  >> 0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1
> => 1.0
> 
> Disappointing that JRuby does not handle floating point numbers (a) in 
> the the same way as CRuby and (b) not as accurately.  Is the cost of 
> implementing CRuby's behavior prohibitively high on the JVM, is there a 
> fix planned in the future?  How would JRuby users recommend handling 
> currency on that platform?
> 
> steven

irb(main):001:0> printf "%20.18f", 0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1
0.999999999999999889=> nil


irb(main):004:0* RUBY_VERSION
=> "1.8.6"

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407