From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,b375f07e05d12c7a
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-08-13 01:07:46 PST
Path: 
 archiver1.google.com!news2.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed00.sul.t-online.de!t-online.de!newscore.gigabell.net!fu-berlin.de!uni-berlin.de!ailinel.cbb-automation.DE!not-for-mail
From: dmitry@elros.cbb-automation.de (Dmitry Kazakov)
Newsgroups: comp.lang.ada
Subject: Re: efficient vector/matrix operations in Ada
Date: Mon, 13 Aug 2001 07:50:33 GMT
Message-ID: <3b7781ea.292937@news.cis.dfn.de>
References: <3B6F40C1.FD215D1D@sneakemail.com>
 <ggIb7.36969$Kd7.22848996@news1.rdc1.sfba.home.com>
 <3B6F5ABC.3C40E189@sneakemail.com>
 <9f6e2b77.0108100854.66b084b4@posting.google.com>
NNTP-Posting-Host: ailinel.cbb-automation.de (212.79.194.99)
X-Trace: fu-berlin.de 997689034 8211747 212.79.194.99 (16 [77047])
X-Newsreader: Forte Free Agent 1.21/32.243
Xref: archiver1.google.com comp.lang.ada:11833
Date: 2001-08-13T07:50:33+00:00
List-Id: <comp.lang.ada>

On 10 Aug 2001 09:54:33 -0700, B_Gaffney@My-Deja.com (B.Gaffney)
wrote:

>"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?

One could allow to define "accelerators" for binary and unary
operations. For instance:

   function "+" (A, B : Matrix) return Matrix;
   procedure InPlaceSum (A : in out Matrix, B : Matrix);
   pragma Accelerator (InPlaceSum, "+");

The compiler should replace calls to "+" with calls to InPlaceSum if
the left argument is temporal. So B+C+D has to be compiled into:

InPlaceSum ("+"(B,C),D)

[or silently ignore the pragma (:-))]

As for +=, it would be nice to extend the set of operators in Ada.
However it should be done in a consistent manner, i.e. for each
operator @ there should a @:= counterpart. Like "<=:=" for "<=". A bit
cumsy, isn't it? And what to do with "and" or "abs"? (:-))

Regards,
Dmitry Kazakov