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Re: isnan in fortran
From: |
Mike Miller |
Subject: |
Re: isnan in fortran |
Date: |
Wed, 11 Apr 2012 07:46:40 -0400 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Apr 11, 2012 at 07:24:18AM -0400, John W. Eaton wrote:
> On 11-Apr-2012, John W. Eaton wrote:
>
> | On 11-Apr-2012, c. wrote:
> |
> | |
> | | On 10 Apr 2012, at 19:00, address@hidden wrote:
> | |
> | | > I think it would be better to rename the files that need this
> | | > treatment to FILE.in.f and then use sed to do the transformation to
> | | > generate FILE.f in the build tree.
> | | >
> | | > jwe
> | |
> | | I am preparing a patch to do that.
> |
> | After giving it some more thought, it might be better in this specific
> | case to have a configure test that checks whether isnan is available
> | in Fortran and if not, adds misc/isnan.f to the list of functions to
> | compile. The misc/isnan.f function could be
> |
> | logical function isnan (x)
> | double precision x
> | if (x != x)
> | isnan = .false.
> | else
> | isnan = .true.
> | endif
> | return
> | end
>
> Uh, except that I have the test and some syntax wrong. How about
>
> logical function isnan (x)
> double precision x
> isnan = x .ne. x
> return
> end
That would be a lot clearer. So is a single-precision NaN guaranteed to
cast to a double-precision NaN value? Or would we need isnan and
disnan?
logical function isnan(x)
isnan = x .ne. x
return
end
logical function disnan(x)
double precision x
isnan = x .ne. x
return
end
Both erfc and derfc will need type declarations for "logical isnan" to
call this function. Will that break the builtin isnan if the compiler
does provide it?
--
mike
- Re: isnan in fortran, (continued)
Re: isnan in fortran, c., 2012/04/11
- Re: isnan in fortran, John W. Eaton, 2012/04/11
- Re: isnan in fortran, John W. Eaton, 2012/04/11
- Re: isnan in fortran, Michael Goffioul, 2012/04/11
- Re: isnan in fortran, c., 2012/04/11
- Re: isnan in fortran, Michael Goffioul, 2012/04/11
- Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran,
Mike Miller <=
Re: isnan in fortran, John W. Eaton, 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, Mike Miller, 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, John W. Eaton, 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, Jordi GutiƩrrez Hermoso, 2012/04/11
Re: isnan in fortran, c., 2012/04/11
Re: isnan in fortran, Mike Miller, 2012/04/11