[SciPy-user] error linking to libg2c on 64-bit machine

[Pearu Peterson]

On Mon, 15 Nov 2004, Giovanni Samaey wrote:

>> 
>> After you'll update scipy_core from CVS, try the following site.cfg:
>> 
>> [atlas]
>> libraries = g2c
>> library_dirs = /apps/prod/local64/lib64/
>
> I am terribly sorry, but this doesn't help...

Hey, don't worry, we are close:)

> I was able to get the install script to find these directories, because I get
>
> Setting PTATLAS=ATLAS
> FOUND:
>   libraries = ['ptf77blas', 'ptcblas', 'atlas', 'g2c']
>   library_dirs = ['/data/home/giovanni/ATLAS/Linux_HAMMER64SSE2_2/lib', 
> '/apps/prod/local64/lib64/']
>   language = c
>   include_dirs = ['/data/home/giovanni/ATLAS/Linux_HAMMER64SSE2_2/include']
>
> which clearly shows my lib64 directory.
>
> However, the fatal command still reads:
>
> /usr/bin/g77 -shared 
> build/temp.linux-x86_64-2.3/Lib/interpolate/_fitpackmodule.o 
> -Lbuild/temp.linux-x86_64-2.3 -lfitpack -lg2c -o 
> build/lib.linux-x86_64-2.3/scipy/interpolate/_fitpack.so
> /usr/bin/ld: /usr/lib/gcc-lib/i486-linux/3.3.2/64/libg2c.a(lread.o): 
> relocation R_X86_64_32 can not be used when making a shared object; recompile 
> with -fPIC
> /usr/lib/gcc-lib/i486-linux/3.3.2/64/libg2c.a: could not read symbols: Bad 
> value
> collect2: ld returned 1 exit status
> /usr/bin/ld: /usr/lib/gcc-lib/i486-linux/3.3.2/64/libg2c.a(lread.o): 
> relocation R_X86_64_32 can not be used when making a shared object; recompile 
> with -fPIC
> /usr/lib/gcc-lib/i486-linux/3.3.2/64/libg2c.a: could not read symbols: Bad 
> value
> collect2: ld returned 1 exit status
> error: Command "/usr/bin/g77 -shared 
> build/temp.linux-x86_64-2.3/Lib/interpolate/_fitpackmodule.o
> -Lbuild/temp.linux-x86_64-2.3 -lfitpack -lg2c -o 
> build/lib.linux-x86_64-2.3/scipy/interpolate/_fitpack.so" failed with exit 
> status 1

This error comes from linking extension module that does not use atlas.
So, the atlas section in site.cfg is not effective here. However,

  cd Lib/linalg
  python setup_linalg.py build

should work (provided that site.cfg is installed in right place).

So, to fix the g2c library path also for _fitpack, use the following 
section in site.cfg (you can remove the corresponding bits in [atlas]):

[numpy]
libraries = g2c
library_dirs = /apps/prod/local64/lib64/

I haven't check but all extension modules in scipy should use numeric. If 
not then linkige should fail at some point but lets deal with that later 
on..

Pearu