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| 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?