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Re: Octave 3.0.1 available for ftp
From: |
Tatsuro MATSUOKA |
Subject: |
Re: Octave 3.0.1 available for ftp |
Date: |
Fri, 25 Apr 2008 03:29:58 +0900 (JST) |
Hello
Thank you John
I'll report the problem to MinGW ML.
Regards
Tatsuro
--- "John W. Eaton" <address@hidden> wrote:
> On 24-Apr-2008, Michael Goffioul wrote:
>
> | On Thu, Apr 24, 2008 at 3:38 PM, Tatsuro MATSUOKA <address@hidden> wrote:
> | > Hello David
> | >
> | > Thank you for your reply.
> | >
> | > --- David Bateman <address@hidden> wrote:
> | > > Wouldn't it better better to have the autoconf test refuse to set
> | > > HAVE_ROUND for mingw rather than hard code in the source..
> Alternatively
> | > > we code test the behavior of the round function in an autoconf test to
> | > > see if it fails for the case near bitmax, though that would be more
> work
> | > > to implement..
> | > >
> | > > D.
> | >
> | > What you said is right. However, I do not have enough knowledge of auto
> tools.
> | > And I cannot understand what is the problem with 'round' implemeted in
> the MinGW g++ 3.4.5.
> | > If you suggest me a autoconf modification, I will test to it and report
> here.
> |
> | The code used internally by MinGW for "round" is the following
> | (http://www.koders.com/c/fidB63EAFA2C117AAFC1CF9FE9691F8DDBE4DD01A22.aspx)
> |
> | double
> | round (double x)
> | {
> | /* Add +/- 0.5 then then round towards zero. */
> | return trunc ( x + (x >= 0.0 ? 0.5 : -0.5));
> | }
> |
> | The problem with this implementation is when x is the vicinity of bitmax: it
> | leads to floating-point overflow (in the mantissa) and produces rounding
> error,
> | For instance if x = bitmax, round(x) => bitmax+1, while it should return
> | bitmax.
> |
> | Octave used to use the above implementation for MSVC, but because of
> | this problem, I switched it to use the (more robust) gnulib implementation.
>
> Please report the problem to the MinGW maintainers. In the meantime,
> it would be helpful to have a configure test that actually tests the
> feature, not just that we are running on a MinGW system. That way,
> the test should automatically switch to using code from MinGW when the
> problem is fixed in their sources.
>
> Thanks,
>
> jwe
>
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- Re: Octave 3.0.1 available for ftp, (continued)
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/22
- Re: Octave 3.0.1 available for ftp, Michael Goffioul, 2008/04/22
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/22
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/24
- Re: Octave 3.0.1 available for ftp, Michael Goffioul, 2008/04/24
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/24
- Re: Octave 3.0.1 available for ftp, David Bateman, 2008/04/24
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/24
- Re: Octave 3.0.1 available for ftp, Michael Goffioul, 2008/04/24
- Re: Octave 3.0.1 available for ftp, John W. Eaton, 2008/04/24
- Re: Octave 3.0.1 available for ftp,
Tatsuro MATSUOKA <=
- about 'round' function on mingw, Tatsuro MATSUOKA, 2008/04/24
- Re: about 'round' function on mingw, Tatsuro MATSUOKA, 2008/04/24
- Re: about 'round' function on mingw, John W. Eaton, 2008/04/24
- Re: about 'round' function on mingw, Tatsuro MATSUOKA, 2008/04/24
- Re: about 'round' function on mingw, Sergei Steshenko, 2008/04/24
- Re: about 'round' function on mingw, Tatsuro MATSUOKA, 2008/04/24
- Re: Octave 3.0.1 available for ftp, John W. Eaton, 2008/04/24
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/25
- Re: Octave 3.0.1 available for ftp, Michael Goffioul, 2008/04/25
- Re: Octave 3.0.1 available for ftp, Tatsuro MATSUOKA, 2008/04/25