From cf6789fd9747e4d43f1b8a4253472358f7e3b956 Mon Sep 17 00:00:00 2001 From: Alexander Hampel Date: Fri, 3 Jan 2020 11:01:08 +0100 Subject: [PATCH] changes to VASP CSC calculations in doc. --- doc/guide/conv_vasp.rst | 2 -- doc/guide/dftdmft_selfcons.rst | 12 ++++++++++-- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/doc/guide/conv_vasp.rst b/doc/guide/conv_vasp.rst index 43fca67c..bc91a810 100644 --- a/doc/guide/conv_vasp.rst +++ b/doc/guide/conv_vasp.rst @@ -394,8 +394,6 @@ with: :: WRITE(99,'(4I6,F12.7," # of spin, # of k-points, # of bands, # of proj, Efermi" )') W%WDES%NCDIJ,NK,NB,NF,EFERMI -Please make sure that mixing in VASP is turned of IMIX=0 for CSC calculations. Otherwise VASP mixes the charge density, which in the worst case removes the effect of CSC completely. - Another critical point for CSC calculations is the function call of `LPRJ_LDApU` in VASP. This function is not needed, and was left there for debug purposes, but is called every iteration. Removing the call to this function in `electron.F` in line 644 speeds up the calculation significantly in the `ICHARG=5` mode. Moreover, this prevents VASP from generating the `GAMMA` file, which should ideally only be done by the DMFT code after a successful DMFT step, and then be read by VASP. diff --git a/doc/guide/dftdmft_selfcons.rst b/doc/guide/dftdmft_selfcons.rst index c585b5f9..6e4db995 100644 --- a/doc/guide/dftdmft_selfcons.rst +++ b/doc/guide/dftdmft_selfcons.rst @@ -168,9 +168,17 @@ VASP has a special INCAR `ICHARG=5` mode, that has to be switched on to make VAS ICHARG = 5 NELM = 1000 NELMIN = 1000 - IMIX=0 -Here, the flag `IMIX=0` ensures that VASP does not mix the new charge density with previous iterations. Technically, VASP runs with `ICHARG=5` in a NSCF mode. Therefore, one needs to make sure to start with a converged `WAVECAR` file! To understand the difference please make sure to read `ISTART flag VASP wiki `_. Furthermore, the flags `NELM` and `NELMIN` ensure that VASP does not terminate after the default number of iterations of 60. +Technically, VASP runs with `ICHARG=5` in a SCF mode, and adding the DMFT +changes to the DFT density in each step, so that the full DFT+DMFT charge +density is constructed in every step. This is only done in VASP because only the +changes to the DFT density are read by VASP not the full DFT+DMFT density. +Moreover, one should always start with a converged `WAVECAR` file, or make sure, +that the KS states are well converged before the first projectors are created! +To understand the difference please make sure to read `ISTART flag VASP wiki +`_. Furthermore, the flags `NELM` and +`NELMIN` ensure that VASP does not terminate after the default number of +iterations of 60. Other DFT codes ---------------