Re: Floating Point Approximations.

From: paul c <toledobythesea_at_oohay.ac>
Date: Wed, 28 Mar 2007 23:43:06 GMT
Message-ID: <e4DOh.84399$DN.46401@pd7urf2no>

Matthias Klaey wrote:
> paul c <toledobythesea_at_oohay.ac> wrote:
>
>

>>Bob Badour wrote:
>>
>>>David Cressey wrote:
>>>
>>>
>>>>Here's another example of floating point errors,  that's even simpler 
>>>>than
>>>>the 21200 plus 2.5% example.

>
>
> [...]
>
>

>>>I translated the above into C, corrected it and expanded on it. The 
>>>naive method below ignores rounding. The aware method is aware of both 
>>>the limitation in the representations and in the range of interest 
>>>(chosen as 5 decimal places based on the useful precision of the float 
>>>type.)
>>>
>>>This is such a trivial example that it should make all programmers who 
>>>don't know what they are doing shudder.

>
>
> [...]
>
>
>

>>IBM would be doing a public service to put Cowlishaw's decimal code in 
>>the public domain.  Don't understand why they don't.
>>

>
>
> Is it this http://en.wikipedia.org/wiki/Mike_Cowlishaw
> that you are referring to? His work seems to be pretty much available
> to the public.
>
> Greetings
> Matthias Kläy

Yes, available for all to see, but if one wants to write a program that uses his code and give it to other people, one needs IBM's permission, at least that was so the last time I checked, about a year ago. As always with IBM, permission involves intricate legalities that most of us can't certify. One could get sued for giving it away to a handful of people or selling it for a few hundred bucks.

I'm not even thinking of the USA when I say this, for all I know the penalties there could be worse than merely being sued.

p Received on Wed Mar 28 2007 - 18:43:06 CDT