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Re: Re: infinities reformulated



  
======= At 2005-06-01, 07:48:05 Aubrey Jaffer wrote: =======

> | Date: Tue, 31 May 2005 15:16:37 +0800
> | From: "Chongkai Zhu" <mathematica@xxxxxxxxx>
> | 
> | I mentioned Mathematica, only for the "inexact number" part of it,
> | not the "symbolic manipluation" part of it. For example, if you
> | want to save the square root of 2 as an inexact number, you can
> | write:
> | 
> | v1=1.414
> | 
> | the precision or the inexact number v1 is 4 (decimal digits);
> | 
> | but you can also write
> | 
> | v2=1.414213562373095048801688724209698078569671875376948073176679737990732478462107038850387534327641573
> | 
> | and v2 will get precision 100 (all these digits are saved into memory).
>
>So in a Scheme implementation which has "arbitrarily big" precision,
>how many digits is (sqrt 2)?  How many digits is (sin 7/5)?
>

To answer your question directly, there could be a parameter (SRFI 39)
telling how many precision should these functions return.

Here I mention the arbitrarily big precision inexact number only for a
possibility. Because Alex Shinn (and you) already points out that
"Infinity in this case could be defined as the range of all real
numbers greater than the largest possible BigFloat using all of memory
for the exponent", I don't think that we should arguing any more on
"arbitrarily big inexact numbers"/"arbitrarily big precision". Instead,
I would like to see your "fixed" implementation of LIMIT.

Cheers,
Chongkai Zhu