[gmx-users] Re: install gromacs on ia64 system

[Erik Lindahl]

Hi,

On Mar 31, 2005, at 10:31 AM, Jian Zou wrote:

>>> David wrote:
>>> Yes, but not necesssarily. Float will still be faster.
>
>> Michel wrote:
>> My tests on the itanium2 revelaed that single precision wouldn't go
>> faster than double, but would produce supernovae out of my simulation
>> box. This is for gromacs 3.2.1. Double precision seems OK.
>
> In my test by now, double precision seems much faster than single, 
> almost twice.
> The gromacs is gmx-3.2.1 & fftw-2.1.5 installed by the administrator, 
> yet I do not know which compiler they chose for gmx & fftw.
>
>
That shouldn't be possible. In worst case single precision is the same 
speed as double, but since it saves a factor 2 in cache usage it is 
often significantly better on large systems.

Cheers,

Erik

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