Re: Is ther any sense in *= and matrices?

[18k11tm001@sneakemail.com (Russ)]

"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.