Re: eigs and ARPACK

[Thomas Treichl]

Thomas Weber schrieb:
> On Sat, Jan 03, 2009 at 08:39:54PM +0100, Thomas Treichl wrote:
> > At the moment I still have the problem that linking of liboctave.dylib 
> > fails because of undefined symbols:
> >
> >   ld: Undefined symbols:
> >   _dnaupd_
> >   _dneupd_
> >   _dsaupd_
> >   _dseupd_
> >   _znaupd_
> >   _zneupd_
> >   /usr/libexec/gcc/i686-apple-darwin8/4.0.1/libtool:
> >     internal link edit command failed
> >
> > that's why I added "$(ARPACK_LIBS)" to "LINK_DEPS" of "Makefile.in" in 
> > the directory of liboctave. I cheated, and also compiled the latest 
> > Octave sources on my virtual Debian GNU/Linux box. That system doesn't 
> > need to know anything about $(ARPACK_LIBS) for liboctave.so but just 
> > compiles fine without that information - can you help me to understand 
> > where GNU/Linux gets it's information about these functions from? 
>
> ld checks /usr/lib (and some other paths) by default.

Sure, but does ld also check each library in these paths for function names ? 
How does ld know that eg. the function "dneupd" is part of /usr/lib/libarpack* 
and is not defined in /usr/lib/libelse.* if not "-larpack" is explicitly used 
for linking? That's where I have the problem of understanding or, as already 
mentioned, I overlook something?!

> How did you install arpack on Debian?

I installed the libarpack-dev package with "apt-get install". Thanks for help 
again,

  Thomas