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Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt)
From: |
Camm Maguire |
Subject: |
Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt) |
Date: |
09 Jan 2003 21:35:41 -0500 |
Greetings!
"Stavros Macrakis" <address@hidden> writes:
> Camm,
>
> That was a quick fix! Thanks! What turned out to be the problem?
>
The issue was that Ldecode_float/double_exponent/set_exponent used
their own bit masking code, and did not use that in
integer-decode-float at all. This together with the fact that certain
algorithms calculated their result inverted and then divided into
1.0 at the end, which of course will overflow when a double is
denormalized.
Take care,
> > ;; although the following is correct code in that it approximates the
> > ;; x to within eps, it does not preserve (eql (float (rationalize x)
> x) x)
> > ;; since the test for eql is more strict than the float-epsilon
>
> I agree that the spec for rationalize is ambiguous, and making it behave
> better is not high priority. But the comment in numlib.lsp doesn't make
> sense, because (float (rationalize x)) should be *precisely* equal to
> x -- I'm afraid I can't look at the code in more detail right now.
> Anyway, this is not a high priority.
>
> Thanks again!
>
> -s
>
>
>
--
Camm Maguire address@hidden
==========================================================================
"The earth is but one country, and mankind its citizens." -- Baha'u'llah
- [Gcl-devel] Re: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/03
- [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Stavros Macrakis, 2003/01/03
- [Gcl-devel] Re: GCL bugs (decode-float, rationalize, expt), Raymond Toy, 2003/01/04
- Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/07
- RE: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Stavros Macrakis, 2003/01/07
- Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/09
- Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/12
[Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Mike Thomas, 2003/01/05
- [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Stavros Macrakis, 2003/01/05
- Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/12
- RE: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Mike Thomas, 2003/01/14
- Re: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Camm Maguire, 2003/01/15
- RE: [Gcl-devel] RE: GCL bugs (decode-float, rationalize, expt), Mike Thomas, 2003/01/15