[gmx-developers] Decimal floating types

[Berk Hess]

Hi,

Yes, but while adding things up it doesn't matter how we round them,
we want as little rounding as possible. We can round to decimals in the
output,
which is anyhow what printf does to make it human readable.
For the particular case of time we never add. We only multiple nsteps by dt.
But dt is not necessarily a decimal nicely rounded number.
Often it's 0.002 ps, but it might be 1/300 ps.

Berk

On 03/03/2011 06:32 PM, Ran Friedman wrote:
> Hi,
> It's a human being that looks at the output, and it can be useful in some cases (e.g., time).
> But I don't know the cost of using these and it's not ANSI.
> Ran
>
> ________________________________________
> From: gmx-developers-bounces at gromacs.org [gmx-developers-bounces at gromacs.org] On Behalf Of Berk Hess [hess at cbr.su.se]
> Sent: 03 March 2011 17:07
> To: Discussion list for GROMACS development
> Subject: Re: [gmx-developers] Decimal floating types
>
> Hi,
>
> I just read up on what decimal floating types are.
> These are for exact decimal rounding.
> But the decimal system is a human invention, only relevant for
> inter-human agreements
> (such as financial affairs). Physics doesn't know anything about decimals,
> so it's irrelevant for Gromacs (unless you want to simulate financial
> markets.
>
> Berk
>
> On 03/03/2011 04:54 PM, Berk Hess wrote:
>   
>> Hi,
>>
>> I don't understand what you mean with decimal floating times.
>> Time in Gromacs is a double since since version 4.0.
>>
>> Berk
>>
>> On 03/03/2011 02:05 PM, Ran Friedman wrote:
>>     
>>> Dear all,
>>> Is there a plan to include decimal floating types in Gromacs
>>> (_Decimal32, _Decimal64)? This can be useful for variables like the
>>> time.
>>> Ran
>>>
>>> ------------------------------------------------
>>> Ran Friedman
>>> Biträdande Lektor (Assistant Professor)
>>>
>>> Linnaeus University
>>> School of Natural Sciences
>>> 391 82 Kalmar, Sweden
>>>
>>> Norrgård, room 328d
>>> +46 480 446 290 Telephone
>>> +46 76 207 8763 Mobile
>>> ran.friedman at lnu.se
>>> http://lnu.se/ccbg
>>> ------------------------------------------------
>>>       
>>     
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