[gmx-developers] May be bug in 64-bit !

[D. Ensign]

Quoting Erik Lindahl <lindahl at cbr.su.se>:

> Hi,
>
> On May 30, 2007, at 3:51 PM, Mark Abraham wrote:
>
>>
>>> 2.         The second problem is due to invalid range value (ci)   
>>> in file: nsgrid.c (Line: 225 & Line: 277)
>>
>> This error comes up all the time on all OS when people haven't   
>> followed a sufficiently gentle minimization and equilibration regime.
>
> Right, but this is something different since it occurs with the demo
> files that are known to work.
>
> For reference, the errors actually never occur is nsgrid.c. However,
> when your coordinates become invalid (usually NaN) for some reason like
> horribly bad structure, compiler bug, file IO error, etc., the first
> place we notice is when we try to put them on the grid to do
> neighborsearching.
>
> We've considered adding more checks, but since those would degrade
> performance slightly we'd have to implement some "-safe" flag or
> similar that you only use when you expect an error...

I, for one, think that would be an excellent addition to the GMX code  
(or possibly a *lot* of excellent additions). Maybe it could be  
#ifdef'd so that you could run a safe-enabled version of mdrun -- this  
would help a lot to those of us who screw with the code, or at least me.

-- 
Daniel L. Ensign
Dept. of Chemistry
Stanford University

--
Quando omni flunkus moritati. -- Red Green