[gmx-developers] energy calculation

[Erik Lindahl]

Vibin R wrote:

>Dear Sir,
>
>   I have been trying to figure out the routine mcinl1100 in the gromacs
>package, version 3.1  Could you be kind to let me know in which code
>this loop is situated. I have searched almost all the relevant codes. 
>
>Sincerely
>Vibin R.
>
>
Hi Vibin,


The source code for all the innerloops is *generated* at compile time, 
to make it possible to optimize the loops for the architecture you are 
compiling on. This way it is also possible to construct the loops in 
fortran if you have a fortran compiler.

If you want to have a look at the source you can go to gmxlib and type 
"make innerc.c" after you have configured the package. This will make 
the (huge) file innerc.c with the C language versions of the loops.

To use the loops, just link with the gromacs library. It is not trivial 
to just copy the source code for a single loop since it might need 
external datatypes (e.g. table lookup data for software inverse square 
root calculations).

Cheers,

Erik