Question about building ScaLapack with ATLAS

[tcarroll]

Hi -
I've gotten ScaLapack to build and run with the reference BLAS. However, I've encountered some errors when attempting to build it with ATLAS. The errors are all from libf77blas.a and are all similar to:

/home/setup/mtj/ATLAS/lib/Linux_UNKNOWNSSE2_2/libf77blas.a(ATL_F77wrap_idamax.o)(.text+0x1b): In function `atl_f77wrap_idamax__':
ATL_F77wrap_amax.c: undefined reference to `ATL_idamax'

I'm currently building this on an Intel Xeon, but will also be building on Athlon machines. Could anyone who's had success with this config point me in the right direction? I'm currently trying this:

I modified the ATLAS makefile to change -DAdd__ to -DAdd_ since that's what is in the BLACS and ScaLapack makefiles...or given the errors, might I want no underscores?

thanks
tom

[Julien Langou]

Hello,

when you want to link with ATLAS from a Fortran application (e.g. ScaLAPACK), you need the two libraries:
-lf77blas -latlas
Your error message really looks as if you have forgotten -latlas (libatlas.a).

Can you check this?

Best wishes,
Julien Langou

[tcarroll]

Hi Julien -
I tried to compile one of the examples with the following

mpif77 -o example1 example1.f libscalapack.a /root/BLACS/LIB/blacsF77init_MPI-LINUX-0.a /root/BLACS/LIB/blacs_MPI-LINUX-0.a /root/BLACS/LIB/blacsF77init_MPI-LINUX-0.a /home/setup/mtj/ATLAS/lib/Linux_UNKNOWNSSE2_2/libatlas.a /home/setup/mtj/ATLAS/lib/Linux_UNKNOWNSSE2_2/libf77blas.a /usr/lib/liblamf77mpi.a

I get the errors that I noted. Based on your suggestion, I removed the reference to libatlas.a and go the exact same error message. So maybe there is something wrong with my libatlas.a? (if you follow my logic)

thanks,
tom

[Julien Langou]

Hello Tom,

keep in mind that when you link with libraries order does matter.

So try
-L/home/setup/mtj/ATLAS/lib/Linux_UNKNOWNSSE2_2 -lf77blas -latlas

First, libf77blas.a then libatlas.a. Not the other way around.

(BTW, I think you can safely remove the liblamf77mpi.a at the end of your linking if you are using mpif77 for the link. Not a big deal if you have it, though.)

Julien

[tcarroll]

Thanks Julien,
That was the error. Sometimes when trying something new, the simpler things are forgotten :).

You'll likely be seeing more questions from me in the near future!

tom