[ESPResSo-devel] c question

[Ivan Cimrak]

Dear core developer(s),


I would like to add some functionality in our object-in-fluid framework. 
We did some effort to speed up the computations. For this however we 
needed to create new local interaction between 4 particles, called 
oif_local_forces (this interaction replaces all other local interactions 
from oif).

Unlike the dihedral force, we need 4 different forces to be added to 4 
particles involved in the interaction.

Until now, the Espresso defines in function add_bonded_forces only 3 
forces (force, force2 and force3). Only when TWIST_STACK is defined, 
another forces are used.

Here comes my question: How should I add the fourth force? There are 
basically 2 options:
1. I add force4 in the beginning  of add_bonded_force. The drawback of 
this option is, that there will be always 4 forces compiled in 
regardless whether our new local bonded interaction will be used or not.
2. I will introduce new preprocessor directive OIF_LOCAL_FORCES that 
will need to be set in myconfig.hpp in case I will use my new local 
interaction. And the fourth force will be defined only if 
OIF_LOCAL_FORCES is defined. I emphasize, that the directive 
OIF_LOCAL_FORCES would be used only at this single place in the code. We 
do not need it for anything else.


Thanks for your advice.

Ivan





--
Ivan Cimrak
FRI Zilinska Univerzita v Ziline
personal web: http://www.kst.fri.uniza.sk/~icimrak/
cell-in-fluid group: http://cell-in-fluid.fri.uniza.sk