3.5.14 scaLAPACK

 

If specified VASP will use scaLAPACK instead of LAPACK for the LU decomposition and diagonalization of the sub space matrix ( ). These operations are very fast in the serial version ( ) but become a bottleneck on massively parallel machine. If scaLAPACK is installed on the parallel machine use this switch. scaLAPACK can be used on the T3E only for programming enviromente 3.0.1.0. (3.0.0.0 does for instance not offer the required routines). On the T3D (but not T3E) the additional switch

 -DT3D_SCA

must be specified, at least for the scaLAPACK version tested by us (the T3D scalapack is not compatible to standard scaLAPACK routines).

scaLAPACK can be switched of during runtime by specifying

 LSCALAPACK = .FALSE.

in the INCAR file. (this is required in the nudged chain mode on the T3D, because currently scaLAPACK on the T3D is not supporting the routine BLACS_GRIDMAP, see Sec. 8.4).

MIND: in the Gamma point only version, the parallel sub space diagonalization (LscaLAPACK= True) is performed with a Jacobi algorithm instead of scaLAPACK. This routine was written by Ian Bush. The Jacobi routine is faster than scaLAPACK.