IWAVPR

IWAVPR = 0 | 1 | 2 | 3 | 10 | 11 | 12 | 13 

Default: IWAVPR	= 2	if IBRION=0 (MD) and 1,2 (relaxation)
	= 0	else (static calculation)

{\tt IWAVPR}= {\tt 0 | 1 | 2 | 3 | 10 | 11 | 12 | 13}

\begin{tabular} {rl} Default: \\ {\tt IWAVPR}=2 & if {\tt IBRION}=0 (MD) and 1,2 (relaxation) \\

           =0 & else (static calculation) \\

\end{tabular} \vspace{5mm}

\noindent {\tt IWAVPR} determines how orbitals and/or charge density are extrapolated from one ionic configuration to the next configuration. Usually the file TMPCAR \index{FILES!T!TMPCAR|textit} is used to store old orbitals, which are required for the prediction. If {\tt IWAVPR} is larger than 10, the prediction is done without an external file TMPCAR (i.e. all required arrays are stored in main memory, this option works from version VASP.4.1). If the {\tt IWAVPR} is set to 10, the reader will set it to the following default values:

\begin{tabular} {ll} {\tt IWAVPRE}=12 & if {\tt IBRION}=0 (MD) \\ {\tt IWAVPRE}=11 & if {\tt IBRION}=1,2 (relaxation) \\ \end{tabular} \vspace{5mm}

\begin{itemize} \item[0] no extrapolation, usually less preferable if you want to do an ab initio MD or a relaxation of the ions into the instantaneous groundstate. \item[1,11] Simple extrapolation of the charge density using atomic charge densities is done (eq. (9.8) in thesis G. Kresse). This switch is convenient for all kind of geometry optimizations (ionic relaxation and volume/cell shape with conjugate gradient or Quasi-Newton methods, i.e. {\tt IBRION}=1,2) \index{INCAR!I!IBRION|textit} \item[2,12] A second order extrapolation for the orbitals and the charge density is done (eq. (9.9) in thesis G. Kresse). A must for ab-initio MD-runs. \item[3,13] In this case a second order extrapolation for the orbitals, and a simple extrapolation of the charge density using atomic charge densities is done. This is obviously a mixture between {\tt IWAVPR}=1 and 2, however, it is usually worse than {\tt IWAVPR}=2.

{\em Mind:} We don't encourage this setting.