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Re: Nitpick with FLOOR etc.

This page is part of the web mail archives of SRFI 70 from before July 7th, 2015. The new archives for SRFI 70 contain all messages, not just those from before July 7th, 2015.

 | Date: Sun, 17 Jul 2005 23:24:49 -0400
 | From: Paul Schlie <schlie@xxxxxxxxxxx>
 | > From: Paul Schlie <schlie@xxxxxxxxxxx>
 | >> The possibility that systems may implement exact infinities rules out
 | >> having the error be with INEXACT->EXACT (passed real infinities).
 | - maybe that implies that infinities and their reciprocals are in a
 | class by themselves, as neither are warranted to have some minimal
 | precision, as both exact and inexact representations have, but
 | rather represent an underflow of the minimal precision otherwise
 | warranted, thereby effectively representing the bounds of an
 | implementation's exact/inexact representations?

Infinity as a number is not what SRFI-70 is about.  In it, inexact
numbers are real neighborhoods and inexact infinities are real
half-lines.  These semantics seem to be working well; but they are not
applicable to exact numbers.

See SRFI-73 for infinity-as-number.

 | ...
 | Thereby it becomes possible that:
 |  (inexact->exact #i1/0) => #i1/0

What would (exact->inexact #e+/0) return?

 | Merely indicating the value was greater in magnitude than the greatest
 | representable inexact value, but less than the greatest representable
 | exact value, but without a minimally sufficient resolvable precision?
 | Implying something along the line of:
 |   #e-1/0     ..  #e-xxx  ..      #e-0/1 0  ...
 |     |     |                   |     |   |
 |        #i-1/0 .. #i-xxx .. #i-0/1       0  ...

Which problem in SRFI-70 does adding two more real infinities solve?