[gmx-developers] real in C++

[David van der Spoel]

On 2013-02-25 16:39, Berk Hess wrote:
> Yes, for this we would want to introduce multiple different reals.
>
But what is wrong with having double and real, as we do now?


> Cheers,
>
> Berk
>
> On 02/25/2013 04:37 PM, Szilárd Páll wrote:
>> One thing to note is that we would like to have an additional mixed
>> precision scheme, hopefully in 5.0. The idea is that part of the code,
>> like force calculations, would run in single precision with fixed
>> precision accumulators/reduction and double for whatever it makes
>> sense/is useful. Using real everywhere could make achieving this quite
>> difficult, right?
>>
>> --
>> Szilárd
>>
>>
>> On Mon, Feb 25, 2013 at 3:50 PM, Mark Abraham
>> <mark.j.abraham at gmail.com <mailto:mark.j.abraham at gmail.com>> wrote:
>>
>>     I'm not aware of a need to change the way we implement this.
>>
>>     Berk and I have mooted the desirability of switching our naming
>>     scheme to "double-" vs "mixed-precision" on the grounds that
>>     aspects of the virial computation have been in double precision
>>     for a long time. We may as well avoid people leaping to the
>>     conclusion that "single-precision" GROMACS must be dodgy because
>>     you need double precision for some aspects of the algorithm.
>>
>>     Mark
>>
>>     On Sun, Feb 24, 2013 at 10:09 PM, David van der Spoel
>>     <spoel at xray.bmc.uu.se <mailto:spoel at xray.bmc.uu.se>> wrote:
>>
>>         Hi,
>>
>>         did we decide on how to treat real variables in C++?
>>         There is nothing stopping us from keeping the same
>>
>>         #ifdef GMX_DOUBLE
>>         typedef double real;
>>         #else
>>         typedef float real;
>>         #endif
>>
>>         that we have use for decades. Or is there reason to change it?
>>
>>         Cheers,
>>         --
>>         David van der Spoel, Ph.D., Professor of Biology
>>         Dept. of Cell & Molec. Biol., Uppsala University.
>>         Box 596, 75124 Uppsala, Sweden. Phone: +46184714205
>>         <tel:%2B46184714205>.
>>         spoel at xray.bmc.uu.se <mailto:spoel at xray.bmc.uu.se>
>>         http://folding.bmc.uu.se
>>         --
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>>
>>
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>>
>>
>>
>
>
>


-- 
David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
spoel at xray.bmc.uu.se    http://folding.bmc.uu.se