[Wien] Compilation on IBM

[Torsten Andersen]

Dear All,

some notes on compilation on IBM p630.

1. ESSL 4.1 is about 5% faster than 3.3 in lapw1c.
2. Compiler options are: -q64 -O5
3. Linker options are: -q64 -O5 -qipa=missing=isolated -L../SRC_lib 
-bmaxdata:0x80000000
4. It is important (especially for lapw2c) to have the optimization 
options in the linking process, too. lapw2c gains about 20% in speed 
because of that.
5. lapack_lapw is an exception. It has to be compiled with -O3, 
otherwise an infinite loop arises in the function DLAMC2, and lapwso and 
lapw1c never finishes.
6. I have experimented with the qipa options, and none of those that are 
not included in the -O5 optimization level seem to have any further 
impact on speed.

Best regards,
Torsten Andersen.


-- 
Dr. Torsten Andersen                     TA-web: http://deep.at/myspace/
AG Hübner, Department of Physics, Kaiserslautern University, and
Condensed Matter Theory Group, Department of Physics, Uppsala University
Web: http://www.fysik4.fysik.uu.se/         http://www.physik.uni-kl.de/