This program allows to perform DFT+DMFT ''one-shot'' and charge self-consistent calculations from h5 archives or VASP input files for multiband systems using the TRIQS package, in combination with the CThyb solver and SumkDFT from DFT-tools. Runs with both triqs 1.4.2 and triqs 2.1. (https://github.com/TRIQS/)

For one-shot calculations one starts directly by running run_dmft.py, whereas for CSC calculations one uses the vasp_dmft.sh bash scripts to start both VASP and triqs at once.

Copyright (C) 2019, A. Hampel, S. Beck and C. Ederer from Materials Theory Group at ETH Zurich.

This application is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version (see http://www.gnu.org/licenses/). You should have received a copy of the License (file: LICENSE) with this repository.

It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Please also note that we do not provide user support for this code.

• run_dmft.py: main file that runs the calculation and start a CSC flow by invoking csc_flow_control or a one shot calculation directly by invoking dmft_cycle on a given h5 archive
• read_config.py: contains the functions to read the dmft config file. Take a look in read_config.py for a detailed list of parameters
• dmft_cycle.py: contains the dmft_cycle function that run a predefined number of DMFT iterations
• csc_flow.py: contains the csc_flow_control function to steer the CSC calculation and call then ones per DFT+DMFT cycle the dmft_cycle function
• observables.py: contains all functions necessary to calculate and write the observables during the run, which are stored in a general dictionary: observables
• toolset.py: contains several small helper functions

For one-shot calculations one starts directly by running run_dmft.py, whereas for CSC calculations one uses the vasp_dmft.sh bash scripts to start both VASP and triqs at once.

In the example directory one finds several examples to run. Best start with the svo-one-shot example. The dmft_config.ini file contains the configuration for the DMFT run, which is explained in the read_config method in the main script. The svo.h5 is the DMFT input data, which is obtained from projection on localized Wannier functions (see folder svo-one-shot/converter).

If one wishes to do CSC calculations the docker container must contain also a installed VASP version >5.4.4 that understands the ICHARG=5 flag.

To run the one shot examples one can use the triqs docker images on, https://hub.docker.com/r/materialstheory/triqs/ or the official ones on https://hub.docker.com/r/flatironinstitute/triqs/.

then one can run docker as:

docker run --rm -it -u $(id -u) -v ~/git/uni-dmft:/work materialstheory/triqs bash

go to the example directory inside the running container and the run it via:

mpirun -n 4 python work/run_dmft.py

or run it directly via:

docker run --rm -it -u $(id -u) -v ~/git/uni-dmft:/work materialstheory/triqs bash -c 'cd /work/tests/svo-one-shot/ && python /work/run_dmft.py'

the more elaborate version of the Docker container found in this repo in the folder Docker can be best started as:

docker run --rm -it --shm-size=4g -e USER_ID=`id -u` -e GROUP_ID=`id -g` -p 8378:8378 -v $PWD:/work -v ~/git/uni-dmft:/uni-dmft triqs_vasp_csc bash

where the -e flags will translate your current user and group id into the container and make sure writing permissions are correct for the mounted volumes. Moreover, you can start by executing

jupyter.sh

a jupyter-lab server from the current dir.

Here one needs a special docker image with vasp included. This can be done by building the Dockerfile in /Docker/:

docker build -t triqs_vasp_csc ./

Then start this docker image as done above and go to the directory with all necessary input files (start with svo-csc example). You need a preconverged CHGCAR and preferably a WAVECAR, a set of INCAR, POSCAR, KPOINTS and POTCAR files, the PLO cfg file plo.cfg and the usual DMFT input file dmft_config.ini.

One starts the whole machinery by calling via bash the vasp_dmft.sh script in the top dir from inside the docker container:

/work/vasp_dmft.sh -n 12 -v 12 /work/run_dmft.py

This will call automatically VASP with -v 12 threads and triqs with -n 12 threads, where triqs starts the specified run_dmft.py. If one now set the csc flag in the dmft_config.ini file to True, triqs will wait for vasp to create PLOs, run the converter, run the dmft_cycle, and then VASP again until the given limit of DMFT iterations is reached.

One remark regarding the number of iterations per DFT cycle. Since VASP uses a block Davidson scheme for minimizing the energy functional not all eigenvalues of the Hamiltonian are updated simultaneously therefore one has to make several iterations before the changes from DMFT in the charge density are completely considered. The default value are 8 DFT iterations, which is very conservative. In general I found, that even in charge ordered systems 6 iterations are enough, but that can of course also differ with system size. Careful testing is advised!

I now use the official Vasp 5.4.4 patch 1 version with a few modifications:

• there is an bug in fileio.F around line 1710 where the code tries print out something like "reading the density matrix from Gamma", but this should be done only by the master node. So I added a IF (IO%IU0>=0) THEN ... ENDIF around it
• in the current version of the dft_tools interface the file LOCPROJ should contain the fermi energy in the header. Therefore I replaced the following line in locproj.F:

WRITE(99,'(4I6,"  # of spin, # of k-points, # of bands, # of proj" )') NS,NK,NB,NF

by

WRITE(99,'(4I6,F12.7,"  # of spin, # of k-points, # of bands, # of proj, Efermi" )') W%WDES%NCDIJ,NK,NB,NF,EFERMI

and added the variable EFERMI accordingly in the function call.

• Vasp gets sometimes stuck and does not write the OSZICAR file correctly due to a stuck buffer. I added a flush to the buffer to have a correctly written OSZICAR to extract the DFT energy. I added in electron.F around line 580 after

CALL STOP_TIMING("G",IO%IU6,"DOS")

two lines:

flush(17)
print *, ' '

which did the job.

• this one is essential vor the current version of the DMFT code. I tried to fasten everything and I figured that Vasp spends a very long time in the function LPRJ_LDApU. I checked and this function is not needed! Is it used for some basic checks and a manual LDA+U implementation. Removing the call to this function in electron.F in line 644 speeds up the calculation by up to 30%! However, originally I added a copy of the file GAMMA to GAMMA.old to keep the original GAMMA file from DMFT. This is not needed now anymore and I removed the shutil copy call in our python code.
• make sure that mixing in VASP is turned of IMIX=0