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From: Ken Hutson
Subject: 3.2.1.3.4
Date: 2 Oct 2005 17:30:40
Message: <43401940$1@news.povray.org>
This is incorrect.

abs(A) Absolute value of A. If A is negative, returns -A otherwise returns 
A.


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From: Warp
Subject: Re: 3.2.1.3.4
Date: 3 Oct 2005 05:20:01
Message: <4340bf81@news.povray.org>
Ken Hutson <ken### [at] goettingcom> wrote:
> This is incorrect.

> abs(A) Absolute value of A. If A is negative, returns -A otherwise returns 
> A. 

  How is it incorrect?

-- 
                                                          - Warp


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From: Kenneth
Subject: Re: 3.2.1.3.4
Date: 5 Oct 2005 09:05:02
Message: <web.4343968c7ae37ccdd47c191c0@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
> Ken Hutson <ken### [at] goettingcom> wrote:
> > This is incorrect.
>
> > abs(A) Absolute value of A. If A is negative, returns -A otherwise returns
> > A.
>
>   How is it incorrect?
>
> --
>                                                           - Warp

abs(A) will ALWAYS return a positive value (or zero, of course.). AFAIK,
that's what "absolute" means.


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From: Mike Raiford
Subject: Re: 3.2.1.3.4
Date: 5 Oct 2005 16:05:25
Message: <4343f9c5$1@news.povray.org>
Kenneth wrote:
> Warp <war### [at] tagpovrayorg> wrote:
>> Ken Hutson <ken### [at] goettingcom> wrote:
>>> This is incorrect.
>>> abs(A) Absolute value of A. If A is negative, returns -A otherwise returns
>>> A.
>>   How is it incorrect?
>>
>> --
>>                                                           - Warp
> 
> abs(A) will ALWAYS return a positive value (or zero, of course.). AFAIK,
> that's what "absolute" means.
> 
> 

Quick quiz: What is the negative of a negative number. (Hint: its not a 
double negative...)

-- 
~Mike

Things! Billions of them!


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From: Ken Hutson
Subject: Re: 3.2.1.3.4
Date: 6 Oct 2005 00:33:06
Message: <434470c2$1@news.povray.org>
Perhaps the word "incorrect" was a poor choice of words. I'm used to seeing 
a simpler definition:

For any real number a, the absolute value of a, is denoted | a | , and is 
defined as:



"Mike Raiford" <mra### [at] hotmailcom> wrote in message 
news:4343f9c5$1@news.povray.org...
> Kenneth wrote:
>> Warp <war### [at] tagpovrayorg> wrote:
>>> Ken Hutson <ken### [at] goettingcom> wrote:
>>>> This is incorrect.
>>>> abs(A) Absolute value of A. If A is negative, returns -A otherwise 
>>>> returns
>>>> A.
>>>   How is it incorrect?
>>>
>>> --
>>>                                                           - Warp
>>
>> abs(A) will ALWAYS return a positive value (or zero, of course.). AFAIK,
>> that's what "absolute" means.
>>
>>
>
> Quick quiz: What is the negative of a negative number. (Hint: its not a
> double negative...)
>
> -- 
> ~Mike
>
> Things! Billions of them!


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From: Warp
Subject: Re: 3.2.1.3.4
Date: 6 Oct 2005 06:54:50
Message: <4344ca3a@news.povray.org>
Ken Hutson <ken### [at] goettingcom> wrote:
> Perhaps the word "incorrect" was a poor choice of words. I'm used to seeing 
> a simpler definition:

> For any real number a, the absolute value of a, is denoted | a | , and is 
> defined as:

  Could you please use proper formatting of a news reply? What I see here
is a bit ridiculous.
  First is your answer, which ends with "is defined as:". Immediately after
that is the whole original article quoted (beats me how that is the
definition of absolute value). After that comes a gif attachment (which,
by the way, shows only as a black square here).

  I know that some braindead newsreader programs, when hitting the reply
button, will quote the entire original article, put some empty lines
*before* it and then put the cursor at the beginning, and this will tempt
you to just write your answer there. However, for the sake of clarity that's
a bad idea.

  Quote only *relevant* parts of the original post. Keeping the entire
original post is just a waste of bandwidth.
  Answer *after* the quote. If you are answering to several things in
the original post, put each individual answer after each individual
quote. It should look like this:


Some Name wrote:
> Some text.

My answer to this.

> More text.

Another answer.

> Yet more text.

Yet another answer.


  If the original post is long and you are answering to it as a whole,
not particularly to any specific part of it, then you can leave the quote
out completely. People will be able to read the original post you are
answering to if they want. You don't need to repeat it.

-- 
                                                          - Warp


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From: JYR
Subject: Re: 3.2.1.3.4
Date: 6 Oct 2005 14:00:00
Message: <web.43452dbf7ae37ccd6cc14b5c0@news.povray.org>
"Ken Hutson" <ken### [at] goettingcom> wrote:
> Perhaps the word "incorrect" was a poor choice of words. I'm used to seeing
> a simpler definition:
>
> For any real number a, the absolute value of a, is denoted | a | , and is
> defined as:
> |a| = square root of (a squared)

Maybe they don't provide the definition for people who are already "used to
seeing it"... :)

JYR


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From: Kenneth
Subject: Re: 3.2.1.3.4
Date: 6 Oct 2005 21:00:00
Message: <web.4345901d7ae37ccd9e16f59b0@news.povray.org>
Mike Raiford <mra### [at] hotmailcom> wrote:

> Quick quiz: What is the negative of a negative number. (Hint: its not a
> double negative...)

Let me clarify my earlier post, with a nod to Mike Raiford's clue.  I can
see now why there's a bit of confusion. POV's description is correct,
though "worded" in mathematical terms.


Say that A = 32.

abs(A) will then produce A, which is 32.

Now, say A  = -32.

abs(A) will then, according to the POV doc, produce -A.  Which is - (-32).
Which is again 32.

Voila!


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From: Warp
Subject: Re: 3.2.1.3.4
Date: 7 Oct 2005 06:15:09
Message: <4346126d@news.povray.org>
Kenneth <kdw### [at] earthlinknet> wrote:
> Let me clarify my earlier post, with a nod to Mike Raiford's clue.  I can
> see now why there's a bit of confusion. POV's description is correct,
> though "worded" in mathematical terms.

  Perhaps my mind is too spoiled by mathematics, but I really can't
understand how the definition can be confusing, given that you think
about it even for a second.

  After all, it says "if A is negative the result is -A". What does anyone
expect the result to be, reading and understanding this definition?
  I mean, how else could you say that so that it doesn't sound stupid?

-- 
                                                          - Warp


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From: Kenneth
Subject: Re: 3.2.1.3.4
Date: 7 Oct 2005 17:35:01
Message: <web.4346b1637ae37ccd236949710@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:


>   Perhaps my mind is too spoiled by mathematics....
>                                                           - Warp

: )

It confused ME as well, when I first came across it.  Don't know why...
something about "A being  -A".  Of course you're right. But it just "looks"
odd at first glance (well, to a non-mathematician...)


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