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

Erik Lindahl lindahl at stanford.edu
Tue May 14 21:49:40 CEST 2002

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.



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