Boost logo

Ublas :

From: Gunter Winkler (guwi17_at_[hidden])
Date: 2006-08-01 04:10:20

Riccardo Rossi schrieb:
> Hello Gunter,
> i like your matrix implementation as it is reasonably simple and (as
> i understand) it does not have the overhead of the two sizes :-)
> please find attached our own "Tiny Vector" that should be the the
> perfect companion for it... it is a little more complicated but i guess
> this depends on our little experience inside the ublas :-D
After reading a few lines of your code I thought your class is the same
as ublas::bounded_vector. You have a dynamic size vector inside a fixed
size storage array. IMHO a real fixed size vector should only allow
exactly one size which is given by the template parameter.

about the possible perfomance: If we had a fixed size matrix and a fixed
size vector we could specialize all combinations of prod() to get
maximal performance (but this is typically the goal of atlas and not
ublas). I don't think we should double the work of the atlas team. Maybe
there is an easy way to directly map the specialized prod(), axpy_prod()
to some atlas core routines. The only thing we should do is to give the
compiler a chance to optimize as good as possible. This can be done by
creating lots of specializations (by a shell script) that are as simple
as possible.

about the iterators: I chose indexed iterators for simplicity. Maybe
"pointer" interators give better performance.