From: Gerard Jungman <jungman@lanl.gov>
To: GSL Discuss Mailing List <gsl-discuss@sourceware.org>
Subject: Re: gsl container designs
Date: Fri, 08 Jan 2010 20:08:00 -0000 [thread overview]
Message-ID: <1262981361.27244.383.camel@manticore.lanl.gov> (raw)
In-Reply-To: <alpine.LFD.2.00.1001062138040.3462@localhost>
On Wed, 2010-01-06 at 22:29 -0500, Robert G. Brown wrote:
> However, some of my beowulfish friends who work(ed)
> for compiler companies argued that one of Fortran's longstanding
> advantages in numerical code efficiency is simply because of the fact
> that matrices in Fortran are written in stone and so compiler writers
> can optimize the hell out of them. C pointers, OTOH -- well,
I think the main difference is that fortran can assume no aliasing,
which allows some extra optimization that C cannot do. The new
'restrict' keyword is supposed to help with this, but we'll see.
> I've written code to do so many times -- Numerical Recipes provides the
> basic idea in its matrix-packing routines. Simply allocate e.g.
>
> double **..*m,*v;
I understand the mechanics of it. I'm not sure what my concern was;
I thought about this a few months ago and decided there was some
semantic problem. But it looks like the **..*m has exactly the
same life-cycle and maintenance as *v, so I'm not sure what I
was thinking. It might come back to me.
> I can probably dig this code out and post it here (or post a link to it)
> if you want to look at it. I think I went up to 9 or 10 dimensions (way
> more than I needed) and did a lot of things via brute force to make the
> purely mechanical recursion obvious; I planned an eventual rewrite into
> a more compact form that I never got around to.
Sure. Feel free to post it. I like to look at everything and
cherry-pick the best parts from other people's stuff. Makes
things a lot easier.
--
G. Jungman
next prev parent reply other threads:[~2010-01-08 20:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 0:55 Gerard Jungman
2009-11-29 21:04 ` Brian Gough
2009-12-04 18:48 ` Brian Gough
2009-12-09 21:04 ` using GSL with C++ (was Re: gsl container designs) James Amundson
2009-12-09 21:14 ` Jochen Küpper
2009-12-09 21:54 ` Jari Häkkinen
2009-12-10 11:46 ` Brian Gough
2009-12-10 12:09 ` Brian Gough
2009-12-10 13:42 ` Robert G. Brown
2009-12-10 21:44 ` James Bergstra
2009-12-10 15:15 ` Kevin H. Hobbs
2010-01-06 11:45 ` gsl container designs Tuomo Keskitalo
2010-01-06 15:47 ` Robert G. Brown
2010-01-07 1:50 ` Gerard Jungman
2010-01-07 3:29 ` Robert G. Brown
[not found] ` <4a00655d1001062110m139c0a8tf2eae7de67da8f6f@mail.gmail.com>
2010-01-07 5:46 ` Rhys Ulerich
2010-01-07 13:22 ` Robert G. Brown
2010-01-08 20:08 ` Gerard Jungman [this message]
2010-01-07 18:29 ` Brian Gough
2010-01-06 12:04 ` Tuomo Keskitalo
2010-01-06 19:57 ` Gerard Jungman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1262981361.27244.383.camel@manticore.lanl.gov \
--to=jungman@lanl.gov \
--cc=gsl-discuss@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).