[gmx-users] Illegal divion by zero lipid+protein+solvent

[Poncho Arvayo Zatarain]

Hello gromacs users: I know this question is very common but i have this problem: I´m trying to obtain area per headgropu of a dppc+protein+solvent membrane and when i use GRIDMaAT it appears: illegal division by zero. My coord_file is my gro file, file type is gro, num_frames 1, num lipid types 1, resname 1 is DPPC, atomname 1 is P, resname2 and atomname 2 is none and solvent is TIP3. What could be the problem? Also, i run the same area per headgroup with dppc+solvent (with no protein) using the same atomname and resname and have no error. Or could i use the formula:

APL = (box_x * box_y) / N_lipids_per_leaflet?


Thanks