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6.15 Memory requirements

 

The memory requirements of VASP can easily exceed your computer facilities. In this case the first step is to estimate where the excessive memory requirements come from. There are two possibilities:

Try to reduce the memory requirements by reducing the corresponding parameters. See section 10 for a discussion on the minimal requirement of these parameters.

For a more accurate calculation of the memory requirements use the following sheet:

MPLWM = NGXF*NGYF*NGZF/2 or
MPLWV = NGX *NGY *NGZ
LMDIM
NIOND*LMDIM
IRMAX
NRPLWV
NIOND
NBANDS
minimal alloc (NEDOS=300) 4-10 Mbytes
arrays on large grid ( 5 + NTYP )*MPLWVM*16
arrays on small grid 3.5 *MPLWV *16
wavefunctions (NRPLWV+2*NIOND*LMDIM)*(NBANDS+IADD)*IG
real space projectors IRMAX*(LMDIM+2)*NIOND*8
rotation matrizes 3*NBANDS*NBANDS* IG
total

IG=16 for COMPLEX version
IG=8 for gamma point only version
IADD= 2 without residual minimization, 10 with residual minimization

arrays on large grid:
CHTOT, DENCOR, CHTOTL, (CHGGA,CVTOT), CSTRF(NTYPD)
CWORK1, CWORK2

arrays on small grid
CHDEN, CV, CWORK3, CWORK4

wavefunctions
CPTWFP, CPROJ, CPROTM

real space projectors
RPROJ, CRREXP

rotation matrices
CHAM,(COVL,CTMP),CHAMIN

(..,..) means equivalence

In vasp.4.4 the memory requirements can be also calculated by the makeparam utility, which is supplied in the vasp.4.4 directory. It can be created by typing

> make makeparam
in the vasp.4.4 directory.


next up previous contents
Next: 7 The INCAR File Up: 6 The param.inc file Previous: 6.14 Which parameters are

MASTER USER VASP
Mon Mar 29 10:38:29 MEST 1999