AMBER Archive (2002)

Subject: Re: 64-bit Compilation SUN's forte compiler

From: David A. Case (case_at_scripps.edu)
Date: Mon Oct 28 2002 - 21:41:15 CST

On Mon, Oct 28, 2002, Scott Brozell wrote:
>
> 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.

In my experience, there are some cases for sander where -n32 is quite a bit
faster than -64 on SGI processors. This is why we have specified -n32
compilation, even for machines where the default is -64. I don't have
details handy right now, but there are only a few, pretty unusual, situations
where sander requires 64 bit addressing. Nmode, is another story, and
we often compile 64-bit versions in order to do normal mode analysis.

..hope this helps...dac 

-- 

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David A. Case                     |  e-mail:      case_at_scripps.edu
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