Re: 64-bit Compilation SUN's forte compiler

From: Scott Brozell <>
Date: Mon 28 Oct 2002 16:00:08 -0800 (PST)


Generally, a 64 bit addressable executable is only recommended for
applications that require the extra addressing space because a
32 bit addressable executable will have superior performance by a
couple of percent.
For reference, I do not believe that the large benchmark rt_polymerase
requires 64 bits, but I haven't verifyed this recently.

I have not built Amber on a Sun platform, but have built lots of
software on Suns. The default address size is platform dependent
and -fast will very probably give the best choice.
Regarding performance, the default optimization level included by the
-fast option is O4; hence, one might alter Machine.sparc like this
setenv L3 "f90 -c -fast -O3 "
setenv L3 "f90 -c -fast "

Also one could try -fast -O5. Naturally the usual caveats concerning
excessive optimizations apply.

Scott Brozell, Ph.D. | e-mail:
Dept. of Molecular Biology, TPC15 | fax: +1-858-784-8896
The Scripps Research Institute | phone: +1-858-784-8754
10550 N. Torrey Pines Rd. | home page:
La Jolla CA 92037 USA |

On Mon, 28 Oct 2002, Fernando Martin wrote:

> Hi,
> I was wondering if anyone had tinkered with compiling AMBER7 in 64-bit
> mode using SUN's forte compilers. The 'Machine.sparc' provided with the
> distribution seems to default to a 32-bit compilation. All thoughts/shared
> experiences will be greatly appreciated. Thanks in advance,
> Fernando
Received on Mon Oct 28 2002 - 16:00:08 PST
Custom Search