[CPMD-list] How to compile for Sun machine

[Axel Kohlmeyer]

On Wed, 2 Apr 2003 16:27:45 -0500  mkosmows wrote:

> Dear CPMD community:

hi mark,

> 
> I've recently put CPMD (3.7.1) on an old Sun Ultra30 and compiled using 
> ForteDev 7 (now called Sun Studio 7 I believe).  I used the Conifgure SUN 
> option to generate the makefile.

you are probably better off using the SUN-ULTRA3-32BIT configuration(s)
and then change the -xtarget=ultra3 and  -xarch=v8plusb flags to the
appropriate values.

> 
> I can run a job, but get a bit different result than with PC Linux, and the

small(!) differences (especially in the gradients and forces) due to 
different rounding errors in optimized libraries and optimizing strategies 
in different compilers are to be expected. 

> following warning:
> 
> Note: IEEE floating point exception flags raised:
>      Inexact, Underflow;
> Nonstandard floating point mode enabled
> See the Numerical Computation Guide, ieee_flags(3M), ieee_sun(3M)

this one can be ignored. nonstandard floating point was a big win with
_very_ old sun cpus (according to the manpage) so it is automatically 
turned on with -fast. with cpus currently in use you can safely set 
-fns=no and get rid of the warning (IIRC it is still printed once 
at the end of the job, but not all the time).

> 
> I am assuming that I need to do something to the makefile.  If anyone knows, 
> please inform me.  Also, I am planning on purchasing a Sun Blade 150 
> workstaion soon, will the makefile need to be modified for that as well?

see above. please note that you should only compile in 64-bit mode, 
if you use more than 2GB memory. 32bit is from my experience significantly faster.

> 
> Thank you very much,
> 
> Mark Kosmowski

hope this helps,
	axel kohlmeyer.
	
> 
> Chemistry Department
> Syracuse University
> mkosmows at syr.edu
> 
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--

=======================================================================
Axel Kohlmeyer      e-mail:  axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum                   http://www.theochem.ruhr-uni-bochum.de
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.