[gmx-developers] floating points in src/gmxlib/nrnb.c

[Erik Lindahl]

David van der Spoel wrote:

>On Tue, 14 May 2002, Mehmet Suezen wrote:
>
>>Dear Gromacs Team,
>>
>>How one determine flops of innerloops as appeared in the routine nrnb.c?
>> { "Bham",                      128 }, 
>> { "Bham+ Coul",                270 }, 
>>
>go trhough the code and count...
>

For the inner loops it is actually done automatically (all those little 
"nflop" returned by the routines in mkinl_*.c) if you enable comments in 
the generated code - the number of flops will be written at the end of 
each loop.

Everything except the square root counts as one flop; for the inverse 
square root we use the amount of flops needed (5) to do the software 
table lookup.

Cheers,

Erik