To support different machines and different version vasp relies heavily on the C-precompiler (cpp). The cpp is used to create *.f files from the *.F files. Several flags can be passed to the cpp to generate different versions of the *.f files: Following flags are currently supported:
single_precission single precession BLAS/LAPACK calls (single_BLAS for VASP.4) vector compile vector version essl use ESSL call sequence for DSYGV NGXhalf charge density reduced in X direction NGZhalf charge density reduced in Z direction wNGXhalf gamma point only reduced in X direction wNGZhalf gamma point only reduced in Z direction NOZTRMM do not use ZTRMM REAL_to_DBLE change REAL(X) to DBLE(X)VASP.4 only:
debug gives more information during run noSTOPCAR do not re-read STOPCAR file F90_T3D compile for T3D MPI parallel version MPI_CHAIN serial version with nudged chain support scaLAPACK use scaLAPACK (parallel version only) T3D_SMA use shmem communication on T3D instead of MPI MY_TINY required accuracy in symmetry packageThese flags are usually defined in the makefile in the cpp line with
-Dflag