Thorsten Froehlich wrote:
> In article <3e6cc573@news.povray.org> , gimi <gim### [at] psicoch>  wrote:
>>(source: http://www.cs.uu.nl/~daan/papers/divmodnote.html)
>
> Because someone on some webpage says this makes my statement incorrect?

no, it's that it is *plain wrong* that makes it incorrect.

your statement was that Anders was wrong, and i showed
that this is is not true. - get it?

i quoted this page because it was the first hit
on google.  i looked this up because i wasn't sure
about the details, so i refreshed my memory, kind of.

what pages i quote is completely irrelevant, as long as
the content is correct.  i just couldn't find it in one
of my books right away.

> I am not going to get into an argument over nonsense like this.  Any such
> argument would be pointless because I don't have do defend correct behavior.
> You have to produce credible sources that show the current behavior does not
> follow any logical rules.  And that task, fortunately, is impossible because
> the results in POV-Ray are generated by a well-defined program.

again, you missed by far! - nowhere and in no way did i
suggest that povray (nor any other program or system) did
not behave correctly - i quote again:

Thorsten Froehlich wrote:
> In article <3e6bcf10@news.povray.org> , "Anders K."
> <and### [at] kaseorgcom> wrote:
>> mod(7, 3) = 1
>> mod(-7, 3) = 2
>> mod(7, -3) = 1
>> mod(-7, -3) = 2
> Again, only if you apply random rules you could arrive at this result.
> I could understand you argue for 1,2,2,1 as results for this, but not 
> 1,2,1,2 because that is definitely wrong.

see, you accused Anders of stating something wrong.
i said that no, it is not wrong.  it is a matter of
how you actually define that functions, and if you
do it Anders' way, you will get his results, which
are as correct as povray's or hp's results are, because
they fulfill the relation in the definition that i
have quoted.

Thorsten Froehlich wrote:
> In article <3e6cc573@news.povray.org> , gimi <gim### [at] psicoch>  wrote:
>> this is what both the programmers of povray, and the engineers
>> at hp did, and why the results are different, but neither are
>> *wrong*!
>
> Yes, because you only look at div and mod as one system.  You have to
> consider the use of div without mod.  And then the rounding rules get
> arbitrary as a special case just to fit mod, which in nonsense to do. 
 > And just because engineers at HP didn't know how to produce a logical
> implementation doesn't make their implementation right.

honestly, i don't see where you are trying to get here.

of course the two functions have to be defined on the basis
of the same system, or they would not work (as they have to
sort of "complement" each other). - you cannot use two
different rulesets for creating "div" and "mod" functions;
as they will not generally fulfull the equation in the
definition this way (like using "hp-div" together with
"povray-mod", or whatever).

it is not a question of right or wrong, logical or illogical
implementation.  the question is whether they are consistently
defined, and if they are, they will actually work!


well, i'm going to drink some beer now. cheers!

-- 
the quote has left the building

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