Re: [Boost-users] C++ Performance

From: Maik Beckmann (maikbeckmann_at_[hidden])
Date: 2007-11-29 14:23:50

Am Donnerstag 29 November 2007 20:05:20 schrieb Sohail Somani:
> On Thu, 29 Nov 2007 19:54:35 +0100, Maik Beckmann wrote:
> > PLEASE don't use ublas matrices as pointers! They are not made for this
> > (no virtual destructors for performace reasons).  If you want to avoid
> > copying, allways use references.
>
> I hope you weren't suggesting to do this:
>
> // probably won't even compile, and will
> // hurt you if it does.
> vector_slice<T> & s = subslice(...);

A slice is a lightweight object, copying doesn't hurt.

No, the hint isn't related to slices and ranges.  It's just:

typedef boost::numeric::ublas::matrix<double> matrix_type;
matrix_type At;
// .... fill At ...
matrix_type& cfo = mx;

vs.

matrix_type* cfo = &mx;