Re: C++ is Slow?

From:

=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?= <Erik-wikstrom@telia.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 07 Feb 2008 20:02:44 GMT

Message-ID:

<EtJqj.3576$R_4.2621@newsb.telia.net>

On 2008-02-07 12:26, nw wrote:

Having op[] return a dummy object is a poor idea, it makes it harder to
drop in different implementations. Only do something like that if you
absolutely have to. See the FAQ for more about this subject.
http://www.parashift.com/c++-faq-lite/operator-overloading.html#faq-1...

The FAQ is wrong about this. The choice between [i][j] and
(i,j) should depend on personal preference and local
conventions; both offer exactly the same possibilities for
optimization and supporting different implementations.

My reading was that the FAQ indicates that you can use [i][j] but
tries to steer
you away from it because it will be harder to implement. I'm veering
towards a
Matrix object with a operator() but I find it unfortunate that the STL
doesn't
already provide such an object, doing so would provide a standardized
interface
which would let people create compatible Matrix objects optimized for
different
platforms, spare matrices etc.

Are there are any plans for this to be added to a future standard?

No, (or rather probably not, I am not a member of the committee so I do
not know). It has always been the purpose of the standard library to
supply generic containers and algorithms. For specialised purposes third
part libraries are generally recommended. If you want a library you can
use to perform vector and matrix algebra there are a number of them
available, http://www.oonumerics.org/oon/ have a good list.

--
Erik Wikstr??m