Groups > comp.lang.c > #162096

Re: What does (real) number mean?

From	Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups	comp.lang.c
Subject	Re: What does (real) number mean?
Date	2021-07-29 17:26 +0100
Organization	A noiseless patient Spider
Message-ID	<87wnp93x2p.fsf@bsb.me.uk> (permalink)
References	<f79b41c2-a94f-48c9-bc68-7e3aa581a2a7n@googlegroups.com> <eb3eee1f-fff9-465a-a9bc-b5df32f848b8n@googlegroups.com> <bbe400ff-512d-4984-a88f-1653467992abn@googlegroups.com> <31358abf-a486-48ce-94ef-36616b20086cn@googlegroups.com> <9cf8f398-f885-49a4-ae20-6cb3dc2eb0c6n@googlegroups.com>

Show all headers | View raw

wij <wyniijj@gmail.com> writes:

> On Thursday, 29 July 2021 at 18:11:37 UTC+8, Malcolm McLean wrote:
>> On Thursday, 29 July 2021 at 11:00:54 UTC+1, wij wrote: 
>> > 
>> > The view of real number is different from common math. which clib follows: 
>> > floating-point number is 'hoped' to represent real number. 
>> >
>> Floating point number are a sufficient approximation to real numbers for most 
>> purposes. The exception is when doing certain types of mathematics itself.
>
> Precisely, FP is an encoding of number in (binary) scientific notation.
> Floating-point number almost represents an approximate number.

It's more accurate to say that floating-point numbers are exact.

> The error accumulates.

Yes.  The results of operations (and that includes input and the
conversion of source-code literals) may not be representable.  Most
quality implementations will give very tight bounds on the acceptable
error for each operation.  For example, most implementations will expend
considerable effort to convert a decimal literal to the nearest
representable floating point number.

-- 
Ben.

Thread

What does (real) number mean? wij <wyniijj@gmail.com> - 2021-07-27 08:40 -0700
  Re: What does (real) number mean? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-27 10:52 -0700
    Re: What does (real) number mean? wij <wyniijj@gmail.com> - 2021-07-27 16:14 -0700
  Re: What does (real) number mean? "minf...@arcor.de" <minforth@arcor.de> - 2021-07-28 00:24 -0700
    Re: What does (real) number mean? wij <wyniijj@gmail.com> - 2021-07-29 03:00 -0700
      Re: What does (real) number mean? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-07-29 03:11 -0700
        Re: What does (real) number mean? wij <wyniijj@gmail.com> - 2021-07-29 09:21 -0700
          Re: What does (real) number mean? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-29 17:26 +0100
            Re: What does (real) number mean? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-29 17:37 -0400

csiph-web