All of pmemd just uses "double precision" instead of "real". The use of
"double precision" is I think deprecated in the latest fortran standards,
but it is really clear what you are doing, and they may deprecate the usage,
but it is unlikely to go away, given the wide use. The whole "kind" system
focuses on the range of values you can represent, which certainly is
mathematically useful. But for a lot of computer-related issues, it is
actually (at least to me) also useful to know how much storage is required.
The two are related, but not precisely - depends on the exact nature of the
number representation, especially for floating point, and also I think that
there is an "at least" sense to "kind", so the compiler maker can just use
more storage than required to represent a specified range.
Regards - Bob Duke
----- Original Message -----
From: "Jason Swails" <jason.swails.gmail.com>
To: "AMBER Mailing List" <amber.ambermd.org>
Sent: Saturday, May 01, 2010 10:25 AM
Subject: Re: [AMBER] size of real
> Hello,
>
> On Sat, May 1, 2010 at 9:03 AM, sop dadoun <dadoun.sop.gmail.com> wrote:
>
>> Dear amber users,
>>
>> I would like to know the size of real for a fortran program used in amber
>> with Pentium 4 CPU.
>>
>
> Most amber programs include the file $AMBERHOME/include/dprec.h or .fh,
> depending on what version of amber you're talking about. The precision of
> _REAL_ depends on the preprocessor flags that are given to (u)cpp.
> Typically, though, they're double unless you modify something.
>
> All the best,
> Jason
>
> Thanks you for rplying
>> Best regards,
>> Sophie
>> _______________________________________________
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>> AMBER.ambermd.org
>> http://lists.ambermd.org/mailman/listinfo/amber
>>
>
>
>
> --
> Jason M. Swails
> Quantum Theory Project,
> University of Florida
> Ph.D. Graduate Student
> 352-392-4032
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber
>
>
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Received on Sat May 01 2010 - 08:00:03 PDT
