Re: [boost] C++ Performance

From: Lars Gullik Bjønnes (larsbj_at_[hidden])
Date: 2007-11-25 12:28:47

"John Maddock" <john_at_[hidden]> writes:

| uBlas has bindings for various BLAS libraries in the sandbox which speed 
| things up quite a bit.  Also if your program has debug settings turned on 
| then uBlas will be *very* slow, it's only when you turn on all your 
| compiler's optimisations (and maybe define NDEBUG) that uBlas gets up to 
| speed.

You have to define NDEBUG to get anything close to decent performance
out of ublas. We have in some tests seen something close to an order
of three magnitudes improvement with NDEBUG defined.

Which brings be to a nother point: It is _very_ bad of a library to
require of the application to define NDEBUG to work properly.
(The application should be able to decide for itself how NDEBUG/assert
should be used.)
Ublas should stop using NDEBUG and create their own BOOST_UBLAS_DEBUG
or similar and use that instead.

And I should probably go pester the ublas guys as well...

-- 
    Lgb