Re: Newbie: uBLAS slow?

"Thomas Willhalm" wrote in message news:alpsjb$j20$1@main.gmane.org...

Hello,

I'm new to ublas, so it's easily possible that I overlooked something obvious. The first thing I tried to calculate was the following line:

numerics::matrix<double> M(dimension,n); numerics::matrix<double> Covariance = numerics::prod(M,numerics::trans(M))/n;

where dimension is 50 and n is 8000.

Unfortunately. it turned out that the following "stupid" code actually performs better:

numerics::matrix<double> Covariance(dimension,dimension); for (int i=0; i

What am I doing wrong?

I'm using gcc 2.95.3 under Linux 2.4.18 on a mobile Pentium III, if it matters.

How much of a performance difference are you seeing? (I assume that you were using an optimized build.) I expect that you pay *some* price for using nicer abstractions. I've been playing around with uBLAS for a couple of weeks, but haven't really considered its performance yet. I've been re-learning my linear algebra at the same time, so it's been slow slogging. :-)