[gmx-users] Compiling Gromacs 3.2.1 on IBM p690+ Power4

[Fiona Reid]

Dear Gromacs Users, 

A number of users reported problems in getting Gromacs 3.2.1
running on IBM p690+/Power4. With the benefit of advice from
Angelo Rossi (IBM) and Renate Dohmen (Max Planck Institute) 
I have managed to prepare working executables which use 
both the fftw and mass libraries. The executables have been 
tested on several benchmarks (including dppc, gmxdemo & 
water demo) so far all the runs have been successful. 

The options used to compile the code are below:

# Environment variables:
export MPICC="mpcc_r -q64" 
export CC="xlc_r -q64"
export F77="xlf_r -q64"
export OBJECT_MODE=64
export LDFLAGS="${LDFLAGS} -L/usr/local/packages/fftw/lib"
export CPPFLAGS="${CPPFLAGS} -I/usr/local/packages/fftw/include"
export FFLAGS="-O3 -qarch=pwr4 -qtune=pwr4 -qmaxmem=-1"
export CFLAGS="-O3 -qarch=pwr4 -qtune=pwr4 -qmaxmem=-1"

# For single precision serial version use
./configure --disable-float --disable-vectorized-sqrt 
--prefix=/hpcx/home/z001/z001/fiona/gromacs/gromacs_3.2.1
make

# For single precision mpi version of mdrun use
./configure --enable-mpi --disable-float --disable-vectorized-sqrt
--program-suffix="_mpi_d" --prefix=/hpcx/home/z001/z001/fiona/gromacs/gromacs_3.2.1
make mdrun

# For double precision serial version use
./configure --enable-float --disable-vectorized-sqrt 
--prefix=/hpcx/home/z001/z001/fiona/gromacs/gromacs_3.2.1
make

# For double precision mpi version 
./configure --enable-mpi --enable-float --disable-vectorized-sqrt
--program-suffix="_mpi" --prefix=/hpcx/home/z001/z001/fiona/gromacs/gromacs_3.2.1
make

The inclusion of the "--disable-vectorized-sqrt" option is essential,
without this the mdrun will either segmentation fault or produce
NANQ values. 

I hope you find this information useful. 

Best regards, 

Fiona