Re: Re: Re: 答复: compilation of namd

From: Jim Phillips (jim_at_ks.uiuc.edu)
Date: Thu May 12 2011 - 12:32:28 CDT

I just want to point out that the nonbonded code already uses
CXXNOALIASOPTS which contains -fno-alias (Itanium needed it to software
pipeline, x86 benefits some), so -ansi-alias won't add anything there.

-Jim

On Thu, 12 May 2011, Axel Kohlmeyer wrote:

>> Thanks for the information. I 'll test if namd performs better with -O2 and -
>> no-vec then with my current flags and leave it that way.
>
> i would do one more iteration with and without -ansi-alias.
> this flag is not enabled by default (strangely, considering
> all the other quite aggressive and less promising flags
> that are enabled by default), but would give the compiler
> more freedom to optimize memory accesses, which is
> almost always helpful (if the code is written according to
> ANSI standard, that is).
>
> cheers,
> axel.
>
>>
>> Cheers,
>> Bjoern
>>
>> --
>> Bjoern Olausson
>> Martin-Luther-Universitt Halle-Wittenberg
>> Fachbereich Biochemie/Biotechnologie
>> Kurt-Mothes-Str. 3
>> 06120 Halle/Saale
>>
>> Phone: +49-345-55-24942
>>
>
>
>
> --
> Dr. Axel Kohlmeyer
> akohlmey_at_gmail.com http://goo.gl/1wk0
>
> Institute for Computational Molecular Science
> Temple University, Philadelphia PA, USA.
>

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