At the -point half the storage for the wavefunctions can be saved if one of these flags is used because
Mind: If this flag is changed in the makefile, recompile all *.F files. This can be done using
touch *.F make vaspIt is a good idea to compile the -point only version in a separate directory (for instance vasp_gamma). Copy all files from vasp to vasp_gamma, copy makefile.machine to makefile, and edit the makefile. Add the wNGXhalf (or wNGZhalf) flag to the cpp line.
CPP = ... cpp ... -DNGXhalf -DwNGXhalf ...Usually the -point only version is 2 times faster than the conventional version.