From: 18k11tm001@sneakemail.com (Russ)
Subject: Re: efficient vector/matrix operations in Ada
Date: 13 Aug 2001 12:45:43 -0700
Date: 2001-08-13T19:45:44+00:00 [thread overview]
Message-ID: <bebbba07.0108131145.8e90df5@posting.google.com> (raw)
In-Reply-To: 9f6e2b77.0108100854.66b084b4@posting.google.com
B_Gaffney@My-Deja.com (B.Gaffney) wrote in message news:<9f6e2b77.0108100854.66b084b4@posting.google.com>...
> "Russ P." <18k11tm001@sneakemail.com> wrote in message news:<3B6F5ABC.3C40E189@sneakemail.com>...
> > No, you really need the dynamically instantiated temporary matrix, I
> > believe. I've been through this little lesson years ago. Don't forget
> > that you also need to be able to handle expressions such as "A = B + C +
> > D;". You can play complicated games with static arrays of "work"
> > matrices, but you are asking for trouble and the resulting code is
> > likely to not be re-entrant.
>
> Um, OK, but how would you handle this case using your "+="
> implementation? That was your original point wasn't it?
>
> --Bg
Here's how you write "A = B + C + D;" efficiently:
A = B;
A += C;
A += D;
This requires no temporary matrices or passing by value. The original
form (A=B+C+D) is fine for rapid prototyping, but the efficient form
is preferable for production code. As far as I am concerned, Ada
really needs arithmetic assignment operators. Sure, you can use
procedures, but they're intent and effect is not as obvious to the
reader.
Russ
next prev parent reply other threads:[~2001-08-13 19:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-07 1:13 efficient vector/matrix operations in Ada Russ
2001-08-07 2:18 ` Dale Stanbrough
2001-08-07 2:21 ` tmoran
2001-08-07 3:04 ` Russ P.
2001-08-10 16:54 ` B.Gaffney
2001-08-13 7:50 ` Dmitry Kazakov
2001-08-13 19:45 ` Russ [this message]
2001-08-13 20:23 ` Larry Hazel
2001-08-13 21:26 ` Ted Dennison
2001-08-14 4:46 ` Russ
2001-08-14 5:28 ` David Starner
2001-08-14 8:17 ` Alexander Boucke
2001-08-14 8:56 ` Lutz Donnerhacke
2001-08-14 10:54 ` Jacob Sparre Andersen
2001-08-13 21:30 ` Ted Dennison
2001-08-14 4:56 ` Russ
2001-08-14 7:32 ` efficient vector/matrix operations in Fortran, was Re: ... " tmoran
2001-08-14 14:05 ` efficient vector/matrix operations " Ted Dennison
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2001-08-07 11:36 Gautier Write-only-address
2001-08-14 12:37 Gautier Write-only-address
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