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Subject: Re: [boost] New Boost.XInt Library, request preliminary review
From: Chad Nelson (chad.thecomfychair_at_[hidden])
Date: 2010-04-02 13:43:50

Hash: SHA1

On 04/02/2010 02:48 AM, Gottlob Frege wrote:

> I've mostly missed the train on this, but if I could quickly bring up
> a couple of comments from earlier in the thread(s). Paraphrasing:
> 1. infinity is not a number

[Other point removed, as it was addressed by Scott McMurray]

> my responses: [...]
> 1. depends on your definition of 'number'. You can definitely say
> infinity is not an integer. (NaI ?) But for a reasonable definition
> of 'number' infinity IS a number (or more accurately, a bunch of
> numbers, as there is a bunch of infinities).
> The best definition, that I know of for number is "The answer to the
> question: 'how many?' " and infinity fulfills that definition.

Yes, by that definition it's definitely a number. But it's not a
*countable* number, which is the definition that I was using. :-) In
relation to the XInt library, I'd say that an infinity value should also
be counted as a not-a-number, in that an is_nan function should return
true for it -- it's not something that can be calculated with, generally.

> And now some background, and why I bring this up [...]

Thanks for the interesting information.

> Anyhow, feel free to ignore this. I'm not actually taking sides on
> whether/how you treat NaN/infinity - sounds like you may be able to
> avoid it altogether. [...]

If I don't add an infinity value, I could. I'm leaning toward adding one
(with sign), but it will act exactly like a NaN except for comparisons.
- --
Chad Nelson
Oak Circle Software, Inc.
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