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Subject: Re: [ublas] numeric bindings nrm2 differences
From: Kraus Philipp (philipp.kraus_at_[hidden])
Date: 2011-11-29 09:50:43

Am 29.11.2011 um 15:26 schrieb Thomas Klimpel:

> Hi Philipp,
> if you used ATLAS and defined BOOST_NUMERIC_BINDINGS_BLAS_CBLAS, there shouldn't be any problems with return conventions. So as a first step, I recommend to replace the call

This is my "default config" and it creates the problem. The problem exists if I use and if I don't use the CBLAS option

> double norm2 = boost::numeric::bindings::blas::nrm2( v );
> by
> double norm2 = norm_2( v );
> and see whether this gives you the expected results.

no changing if I use the nrm2 or norm2 call. The values are always wrong.
2.3281 is the wrong value and 1.768592181649873 the correct. The value with
norm_2 and nrm2 is equal, but wrong

> Then you can try to call
> double norm2 = cblas_dnrm2( n, x, incx );
> "directly", and see whether the problem still persists. If it does, it might indicate a problem of the used ATLAS library.

The parameter n is the vector.size(), x the vector, isn't it?
 Which definition has incx?