From: sjw <simon.j.wright@mac.com>
Subject: Re: Interfacing Ada with C
Date: Fri, 6 Aug 2010 01:39:18 -0700 (PDT)
Date: 2010-08-06T01:39:18-07:00 [thread overview]
Message-ID: <4a3e5073-5e2b-48d6-b862-9bfd9a5c303e@q35g2000yqn.googlegroups.com> (raw)
In-Reply-To: cc0ad401-3efd-4969-be0b-dae33a1e1035@v15g2000yqe.googlegroups.com
On Aug 5, 6:24 pm, Ada novice <po...@gmx.us> wrote:
> On Aug 5, 3:57 pm, sjw <simon.j.wri...@mac.com> wrote:
>
> > Although LAPACK/BLAS (at 3.2.2 anyway) allow you to build with
> > extended precision (80-bit floats, GNAT Long_Long_Float if on x86
> > hardware) GNAT's implementation of Generic * Arrays assumes the worst
> > case, ie BLAS/LAPACK only available in single & double precision; and
> > if the type in use (My_Float in my test case) doesn't match Fortran
> > single or double precision it converts to double precision, makes the
> > call, then converts back.
>
> Can we change the subtype to Long_Long_Float? This will be of 18
> precision digits and "more" precise than Fortran's double precision.
> It would be like asking for more precision that can be offered. Did I
> understand you correctly?
You can change to Long_Long_Float, and on an Intel machine that will
use 80 bits (on a PowerPC it won't; Long_Long_Float is the same as
Long_Float, because the FPU on a PPC doesn't support extended
precision (AFAIK)).
*BUT* *BUT* *BUT* the internals of the matrix operations (the standard
ones and our extensions) only use 64 bits. So the apparent extra
precision is fool's gold.
next prev parent reply other threads:[~2010-08-06 8:39 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-24 11:57 Interfacing Ada with C Ada novice
2010-07-24 12:08 ` Robert A Duff
2010-07-24 12:32 ` Ada novice
2010-07-24 14:52 ` Marco
2010-07-24 16:38 ` Simon Wright
2010-07-24 17:58 ` Ada novice
2010-07-25 8:29 ` Simon Wright
2010-07-25 12:21 ` Ada novice
2010-07-25 13:50 ` Dmitry A. Kazakov
2010-07-25 14:12 ` Ada novice
2010-07-25 14:17 ` Ada novice
2010-07-25 14:26 ` Simon Wright
2010-07-25 16:18 ` Ada novice
2010-07-25 17:06 ` Dmitry A. Kazakov
2010-07-25 17:42 ` Ada novice
[not found] ` <a5ba4513-ce2b-45d1-a5f4-ff1a7945b0b0@q12g2000yqj.googlegroups.com>
2010-07-25 18:26 ` Dmitry A. Kazakov
2010-07-25 18:52 ` Ada novice
2010-07-25 18:58 ` Dmitry A. Kazakov
2010-07-25 19:13 ` Ada novice
2010-07-25 19:19 ` Dmitry A. Kazakov
2010-07-25 19:28 ` Ada novice
2010-07-25 20:04 ` Dmitry A. Kazakov
2010-07-26 13:40 ` Ada novice
2010-07-26 14:52 ` Dmitry A. Kazakov
2010-07-26 17:14 ` Ada novice
[not found] ` <a2da2804-c19b-44cf-9855-834c602c4520@y11g2000yqm.googlegroups.com>
2010-07-26 17:32 ` Dmitry A. Kazakov
2010-07-26 17:50 ` Ada novice
2010-07-27 12:24 ` Peter Hermann
2010-07-27 19:01 ` Ada novice
2010-07-28 9:56 ` team-ada (was e: " Peter Hermann
2010-07-27 5:50 ` Ada novice
2010-07-27 7:27 ` Dmitry A. Kazakov
2010-07-27 7:43 ` Georg Bauhaus
2010-07-27 18:37 ` Ada novice
2010-07-27 18:40 ` Ada novice
2010-07-25 17:24 ` Simon Wright
2010-07-25 17:47 ` Simon Wright
2010-07-25 17:58 ` Ada novice
2010-07-25 23:21 ` Simon Wright
2010-07-26 1:24 ` John B. Matthews
2010-07-26 14:01 ` Ada novice
2010-07-26 15:46 ` sjw
[not found] ` <da987804-3948-4871-ab52-4a8e95f06d44@k39g2000yqb.googlegroups.com>
2010-07-26 19:46 ` Simon Wright
2010-07-26 20:39 ` Dmitry A. Kazakov
2010-07-27 5:46 ` Ada novice
2010-07-27 5:43 ` Ada novice
2010-07-27 17:33 ` Simon Wright
2010-07-27 18:34 ` Ada novice
2010-07-28 22:26 ` Simon Wright
2010-07-29 9:19 ` Ada novice
2010-07-29 19:14 ` Simon Wright
2010-07-29 20:25 ` Ada novice
2010-07-30 1:46 ` John B. Matthews
2010-07-30 9:09 ` sjw
2010-07-30 12:41 ` Ada novice
2010-07-30 15:13 ` John B. Matthews
2010-07-30 17:25 ` Ada novice
2010-07-30 19:41 ` John B. Matthews
2010-07-30 21:08 ` Ada novice
2010-07-30 22:19 ` Simon Wright
2010-07-31 12:19 ` Ada novice
2010-07-31 13:25 ` Simon Wright
2010-07-31 19:39 ` Ada novice
2010-07-31 21:02 ` Simon Wright
2010-08-01 9:36 ` Ada novice
2010-08-01 16:14 ` Simon Wright
2010-08-01 16:27 ` Ada novice
2010-08-01 17:33 ` Simon Wright
[not found] ` <997036dd-ca13-4cdf-8f88-9b47a9f83b2d@s9g2000yqd.googlegroups.com>
2010-07-31 13:08 ` Simon Wright
2010-07-31 13:17 ` Simon Wright
2010-07-30 15:10 ` John B. Matthews
2010-08-01 10:47 ` John B. Matthews
2010-08-01 17:08 ` Simon Wright
2010-08-02 1:08 ` John B. Matthews
2010-08-02 16:36 ` Simon Wright
2010-08-02 16:55 ` Ada novice
2010-08-05 9:14 ` Ada novice
2010-08-05 13:23 ` John B. Matthews
2010-08-05 13:57 ` sjw
2010-08-05 17:24 ` Ada novice
2010-08-05 17:59 ` Jeffrey Carter
2010-08-05 20:25 ` Simon Wright
2010-08-06 1:15 ` John B. Matthews
2010-08-06 9:11 ` Ada novice
2010-08-06 9:17 ` Ada novice
2010-08-06 8:04 ` Jacob Sparre Andersen
2010-08-06 8:42 ` Dmitry A. Kazakov
2010-08-06 9:26 ` Ada novice
2010-08-06 9:51 ` Dmitry A. Kazakov
2010-08-06 12:04 ` Ada novice
2010-08-06 16:49 ` Simon Wright
2010-08-06 17:27 ` Dmitry A. Kazakov
2010-08-06 18:15 ` Ada novice
2010-08-06 20:26 ` Simon Wright
2010-08-07 0:46 ` John B. Matthews
2010-08-07 7:59 ` Dmitry A. Kazakov
2010-08-07 9:09 ` Georg Bauhaus
2010-08-07 12:33 ` John B. Matthews
2010-08-06 9:49 ` Peter Hermann
2010-08-06 12:03 ` Ada novice
2010-08-07 4:07 ` Randy Brukardt
2010-08-07 8:10 ` Ada novice
2010-08-06 16:41 ` Simon Wright
2010-08-06 8:39 ` sjw [this message]
2010-07-24 16:44 ` Dmitry A. Kazakov
2010-07-24 18:04 ` Ada novice
2010-07-24 19:16 ` Dmitry A. Kazakov
2010-07-25 0:22 ` tmoran
-- strict thread matches above, loose matches on Subject: below --
2003-04-14 21:39 Paul Anderson
2003-04-14 23:05 ` tmoran
2003-04-16 2:56 ` Steve
2003-04-16 4:25 ` Steve
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