Re: [Bug-gsl] gsl_blas_dsyrk in gsl-1.9

[Brian Gough]

At Tue, 22 May 2007 15:57:55 -0700,
Xiaogang Dong wrote:
> I tried to use gsl_blas_dsyrk to calculate the matrix product
> A^TA with A =
> [ 1 2
>   1 3
>   1 4
>   1 5 ].
> The results produced by gsl_blas_dsyrk seems incorrect.
> Bying trying different matrices, I figured out it only used
> the first n rows of an m x n matrix ( assume m > n ).
> For example, instead of calculating A^TA, it actually
> calculate B^TB with B =
> [ 1 2
>   1 3 ].
> 
> My computer is a Dell XPS 410 with Cent OS 4.0 .
> Please let me know if you need more info.

Hello,

Thank you for your bug report.  I believe your program is being linked
against an old version of the library, gsl-1.5 or earlier which had
that bug.  When linked against gsl-1.9 the output of the program is
correct.

$ gcc -Wall -static -I /opt/gsl-1.9/include/ -L /opt/gsl-1.9/lib/ xd.c -lgsl 
-lgslcblas -lm
$ ./a.out 
1.00000 2.00000 
1.00000 3.00000 
1.00000 4.00000 
1.00000 5.00000 

4.00000 0.00000 
14.00000 54.00000 

-- 
best regards,

Brian Gough
(GSL Maintainer)

Network Theory Ltd,
Publishing the GSL Manual - http://www.network-theory.co.uk/gsl/manual/