Re: [boost] is_nan

From: Johan Råde (rade_at_[hidden])
Date: 2006-07-25 06:22:18

John Maddock wrote:
> Joe Gottman wrote:
>>   Several libraries have an is_nan() function buried deep in the
>> code.  Are there any plans to make a general is_nan function
>> available?  This would be quite useful, as well as similar functions
>> like is_finite.
> 
> Yes!  I'm working on these and other functions, see 
> http://www.johnmaddock.co.uk/toolkit for a reasonably recent sets of docs, 
> follow the link to floating point classification.
> 
> HTH, John. 
> 
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I looked at your (John Maddock's) doc. Looks good. This should be very 
useful.

I think the floating point number classification should not be part of 
your math tool kit library, but should be submitted separately. The math 
tool kit is for experts only, while the number classification is of more 
general interest.

So the floating point number classification now goes like:

1. Finite
1.1. Normalized finite
1.2. Denormalized finite
2. Infinity
2.1. Positive infinity
2.2. Negative infinity
3. Not-a-number
3.1. Quite not-a-number
3.2. Signalling not-a-number

I noticed that you do not support the quite/signalling distinction.
I agree that is probably not needed.

--Johan Råde