[Wien] ifort bug (with no optimization flags)

[Laurence Marks]

Being specific, use:

AAA -FR -mp1 -prec_div -pc80 -pad -align -traceback

where AAA=-O0,-O1,-O2,-xHost all give one result that is the same as
the result for ifort 10.X and with gfortran. Omitting the AAA gives a
slightly different result. In most cases this will not matter, but in
some it may

I suggest AAA=-O2

2010/6/17 Jian-Xin Zhu <jxzhu at lanl.gov>:
> Hi Laurence,
> Are you meaning the following compiler options are not enough
> -FR -mp1 -prec_div -pc80 -pad -align -traceback
> and we'd better add  -O2
> as
> -O2 -FR -mp1 -prec_div -pc80 -pad -align -traceback
> to avoid the bug?
> Thanks,
> Jianxin
>
> On Jun 17, 2010, at 7:07 AM, Laurence Marks wrote:
>
> Dear All,
>
> There appears to be a bug in version 11.X of ifort which is not there
> in 10.0 if no optimization flags are used. I would suggest the use of
> -O2, which appears to be safe and gives the same result (within
> numerical error) as gfortran and 10.0 versions. (There is a bug with
> -O3 in symmetry which was previously reported by Gerhard Fecher.)
>
> N.,B., while most people will have used some optimization, the
> siteconfig script does not include any at least in my version of it.
>
> --
> Laurence Marks
> Department of Materials Science and Engineering
> MSE Rm 2036 Cook Hall
> 2220 N Campus Drive
> Northwestern University
> Evanston, IL 60208, USA
> Tel: (847) 491-3996 Fax: (847) 491-7820
> email: L-marks at northwestern dot edu
> Web: www.numis.northwestern.edu
> Chair, Commission on Electron Crystallography of IUCR
> www.numis.northwestern.edu/
> Electron crystallography is the branch of science that uses electron
> scattering and imaging to study the structure of matter.
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> --
> ################################
> Jian-Xin Zhu, Ph.D
> Theoretical Division, MS B262
> Los Alamos National Laboratory
> Los Alamos, New Mexico 87545
> Phone: (505) 667 2363
> Fax: (505) 665 4063
> Email (main): jxzhu at lanl.gov
> Email (backup): physjxzhu at gmail.com
> URL: http://theory.lanl.gov
> ################################
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>



-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
Chair, Commission on Electron Crystallography of IUCR
www.numis.northwestern.edu/
Electron crystallography is the branch of science that uses electron
scattering and imaging to study the structure of matter.