Re: Bug#462232: gsl: Please build depend on libblas-dev instead of refblas3.dev

[Matthias Klose <doko@cs.tu-berlin.de>]

Dirk Eddelbuettel writes:
> 
> Hi Doko,
> 
> I think I have it sorted out.
> 
> On 28 January 2008 at 01:12, Matthias Klose wrote:
> | reopen 462232
> | thanks
> | 
> | Dirk, there are some problems:
> | 
> |  - the current build doesn't use any external blas library, the build
> |    dependencies seem to be bogus.
> 
> That seems to be the same for all gsl builds, not only the newest. I have
> logs of my builds here all the way back from 1.3 in 2003 to 1.10-{1,2,3}.
> 
> So I think this is an upstream choice,

so *why* the build dependency? I checked. It is not needed for the build.

> See the program below. You can build it with _either_ the supplied blas, or
> the regular blas, or Atlas. Your choice. I think that is good:
> 
> edd@ron:~/src/progs/C> gcc -Wall -O2 -o blas_sgemm_gsl_blas blas_sgemm_gsl.c -lblas
> edd@ron:~/src/progs/C> gcc -Wall -O2 -o blas_sgemm_gsl_gslblas blas_sgemm_gsl.c -lgslcblas
> edd@ron:~/src/progs/C> ls -l blas_sgemm_gsl_*
> -rwxr-xr-x 1 edd edd 7105 2008-01-27 19:12 blas_sgemm_gsl_blas
> -rwxr-xr-x 1 edd edd 7105 2008-01-27 19:12 blas_sgemm_gsl_gslblas
> edd@ron:~/src/progs/C> ./blas_sgemm_gsl_blas
> [ 367.76, 368.12
>   674.06, 674.72 ]
> edd@ron:~/src/progs/C> ./blas_sgemm_gsl_gslblas
> [ 367.76, 368.12
>   674.06, 674.72 ]
> edd@ron:~/src/progs/C>  

so why is the duplication of the library a good point? we always strip
off or don't use included copies of zlib, and other stuff. why keep a
copy for this package? with the same reason python-numeric and
python-numarray could use the included copy.

> |  - if the external libs are used, you have to change the name of the
> |    library package.
> 
> I don't understand.

Apparently the package doesn't depend on libg2c0 and was not built
using g77, so you don't need to.
>  
> |  - gsl cannot use the optimized blas libraries provided by atlas, it
> |    really should use the external libs. Or is there a reason not to
> |    do so?
> 
> It can. You'd use it when you build apps against GSL, and by changing your
> Makefiles to point to Atlas instead of the default fallback libgslcblas.
>  
> Gsl being a library, it doesn't actually use blas itself which is why there
> is no depends.  
> 
> Does this make sense now?

well, except that we have another copy of blas in the archive.

  Matthias