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: 103376,8c8550b9f2cf7d40
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-06-09 07:55:05 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newsfeed.cs.utexas.edu!geraldo.cc.utexas.edu!not-for-mail
From: "Bobby D. Bryant" <bdbryant@mail.utexas.edu>
Newsgroups: comp.lang.ada
Subject: Re: Is ther any sense in *= and matrices?
Date: Mon, 09 Jun 2003 08:53:17 -0600
Organization: dis-
Message-ID: <pan.2003.06.09.14.53.15.912223@mail.utexas.edu>
References: <slrnbdu7q9.i9.randhol+abuse@kiuk0152.chembio.ntnu.no>
 <slrnbduaav.6dd.randhol+abuse@kiuk0152.chembio.ntnu.no>
 <bbnb2k$b8a7l$1@ID-175126.news.dfncis.de>
 <slrnbduobb.88r.randhol+abuse@kiuk0152.chembio.ntnu.no>
 <bbnobo$bhcn7$1@ID-175126.news.dfncis.de>
 <slrnbdupg6.88r.randhol+abuse@kiuk0152.chembio.ntnu.no>
 <bebbba07.0306071138.6bf9784f@posting.google.com>
 <bbumef$fnq@library2.airnews.net>
 <bebbba07.0306081051.5f3ac24b@posting.google.com>
 <pan.2003.06.08.22.56.37.297066@mail.utexas.edu>
 <bebbba07.0306082027.2c50eb6b@posting.google.com>
NNTP-Posting-Host: dial-46-69.ots.utexas.edu
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: geraldo.cc.utexas.edu 1055170428 8187 128.83.112.197 (9 Jun 2003
 14:53:48 GMT)
X-Complaints-To: abuse@utexas.edu
NNTP-Posting-Date: Mon, 9 Jun 2003 14:53:48 +0000 (UTC)
User-Agent: Pan/0.14.0 (I'm Being Nibbled to Death by Cats!)
Xref: archiver1.google.com comp.lang.ada:38859
Date: 2003-06-09T08:53:17-06:00
List-Id: <comp.lang.ada>

On Sun, 08 Jun 2003 21:27:13 -0700, Russ wrote:

> "Bobby D. Bryant" <bdbryant@mail.utexas.edu> wrote in message
> news:<pan.2003.06.08.22.56.37.297066@mail.utexas.edu>...
>> On Sun, 08 Jun 2003 11:51:31 -0700, Russ wrote:
>> 
>> > "John R. Strohm" <strohm@airmail.net> wrote in message
>> > news:<bbumef$fnq@library2.airnews.net>...
>>  
>> >> With all due respect, ladies and gentlemen, it has been known for a
>> >> very long time that the difference in "efficiency" between A := A +
>> >> B and A += B is lost in the noise floor compared to the improvements
>> >> that can be gotten by improving the algorithms involved.
>> > 
>> > Oh, really? I just did a test in C++ with 3x3 matrices. I added them
>> > together 10,000,000 times using "+", then "+=". The "+=" version took
>> > about 19 seconds, and the "+" version took about 55 seconds. That's
>> > just shy of a factor of 3, folks. If that's your "noise floor," I
>> > can't help wonder what kind of "algorithms" you are dealing with!
>> 
>> I'm just curious why the compiler didn't generate the same code for
>> both versions.
> 
> The compiler didn't generate the code. I did.

No, I'm talking about the compiler's machine-code output.  You wrote in
C++, right?

-- 
Bobby Bryant
Austin, Texas