[boost] Re: Re: uBLAS and expression templates

From: Benedikt Weber (weber_at_[hidden])
Date: 2002-06-30 09:46:58

"David Abrahams" <david.abrahams_at_[hidden]> wrote

> The problems you are seeing are not due to the avoidance of  temporaries.

Sorry, I am not deeply enough into the problem to understand that. I thought
the problem was that you recalculate intermediate results unnecessarily,
what you can avoid if you keep them in temporaries. It would be interesting
to know how to achieve this efficiency without temporaries. I have to admit
that I am not very familiar with expression templates. I had a glance at
http://osl.iu.edu/~tveldhui/papers/techniques/ but maybe I should read the
whole report in detail. On the other hand, I have experience on numerics
with matrices and I would not know how to evaluate A*B*v efficiently by hand
without keeping the intermediate B*v vector. Or are we talking different
things?

Benedikt