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Re: Nitpick with FLOOR etc.



> From: Aubrey Jaffer <agj@xxxxxxxxxxxx>
> Inverting +/0. or -/0. returns 0.0.  So the name "error object"
> wouldn't seem to apply either.

- I still don't understand how it's acceptable for (/ 1/-0.0) => 0.0, as
  it seems neither necessary, nor desirable to propagate IEEE-754 mistake.

>  | This brings up an important distinction in "infinities;"
>  | When you divide by exact zero you get an absolute infinity.
>  | (which, perversely, is neither positive nor negative, because
>  | exact zero isn't positive or negative.) Call this EO1.
> 
> We have already covered this ground.  Division by zero is undefined;
> SRFI-70 extends division by returning infinities in these cases:
> (/ -5. 0) ==> -/0.; (/ 1. 0) ==> +/0., which are consistent with
> the one-sided limits:
> 
> (limit / 0 1.0e-9)                              ==> +/0.
> (limit / 0 -1.0e-9)                             ==> -/0.

- however as multiplication by 0 should result in 0, 0/x => 0
  regardless of its denominator.

>  | When you divide 1 by (say) 5e-323, you get a different kind of
>  | EO, which is "results too large to represent" but which
>  | is often mistaken for an actual infinity.   Call this EO2.
> 
> The result of division by zero was chosen to be the same as the result
> of (/ 1 5e-323).  We could split +/0 into any number of regions.  One
> was chosen, which happens to be supported by IEEE-754.

- who's model of infinitesimals isn't likely something worthy of mimicking.