Re: arithmetic issues

[Jens Axel Søgaard <jensaxel@xxxxxxxxxxxx>]

Aubrey Jaffer wrote:
>  | From: Thomas Bushnell BSG <tb@xxxxxxxxxx>
>  | Date: Sun, 23 Oct 2005 12:39:43 -0700
>  | 
>  | Aubrey Jaffer <agj@xxxxxxxxxxxx> writes:
>  | 
>  | > When different NaNs are returned depending on the circumstances
>  | > creating them, I would like my implementation to display them
>  | > like this:
>  | >
>  | >   #<not-a-number expt>
>  | 
>  | Sure, that seems fine.  We could mandate that as the readable written
>  | representation!
>
> It should *not* be a readable representation.  That serves only to
> mask mathematical errors in saved datasets.  As Bakul Shah wrote:
> "... IEEE754 says NaN is the result of an *invalid* operation, when an
> operation's operands lie outside its domain."


Say I want to write my own mathematical function and need to return NaN?
E.g.

  (if <check-arguments>
      <calculate-result>
      #<not-a-number>

is, to me, more readable than

  (if <check-arguments>
      <calculate-result>
      (/ 0.0 0.0))

--
Jens Axel Søgaard