Re: MacOSX: Octave.app 2.9.14

[Vic Norton]

I am confused too. Aren't highly optimized BLAS accessible on most  
machines? For example, on my Mac, in "/Developer/SDKs/.../Headers/ 
cblas.h", I see
   double cblas_dnrm2(const int N, const double *X, const int incX);
   double cblas_dasum(const int N, const double *X, const int incX);
These are the norm(x, 2) and norm(x, 1) functions, respectively. They  
should be about as fast as you can get.

Of course this is all theory. I have no idea how to access these  
prototypes. I can't even figure out how to compile octave.

Regards,

Vic


On Oct 3, 2007, at 6:08 PM, Dmitri A. Sergatskov wrote:

> On 10/3/07, John W. Eaton <address@hidden> wrote:
>
> > Is
> >
> >   sum (x .* x)
> >
> > really faster here than
> >
> >   sumsq (x)
> >
> > ?
>
> No. sumsq is faster (at least on my machine).
> But I am confused, isn't call to __vnorm__
> better yet?
>
> > jwe
>
> Dmitri.
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