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44 lines
1.8 KiB
ReStructuredText
44 lines
1.8 KiB
ReStructuredText
.. highlight:: python
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#######################
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Charge self-consistency
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#######################
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Introduction
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************
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Running a DFT+DMFT calculation in the charge self-consistent mode
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requires additional process management whereby the control is given
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to the VASP and to the TRIQS code in an alternating manner.
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It is implemented by a lock system. A VASP process is launched in
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the background and a self-consistency (SC) script in the foreground.
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Once VASP reaches the point where the projectors are generated
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it creates a lock file `vasp.lock` and waits until the lock file is
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removed. The SC script, in turn, waits for the VASP process and once
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the lock file is created it starts a DMFT iteration. The DMFT iteration
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must finish by generating a Kohn-Sham (KS) density matrix (file `GAMMA`)
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and removing the lock file. The VASP process then reads in `GAMMA`
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and proceeds with the next iteration.
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The DMFT iteration is performed using a user-defined script.
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However, the control part is maintained by two universal scripts:
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`sc_dmft.sh` and `sc_dmft.py`.
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The first script, `sc_dmft.sh`, launches the VASP process
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in the background mode, takes its pid, and launches `sc_dmft.py`
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in the foreground mode.
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Both processes are run within an MPI environment with an appropriate
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number of MPI nodes.
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The second script, `sc_dmft.py`, is responsible for the charge self-consitency
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logic described in the first paragraph. It also combines the total
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energy contributions coming from the DFT and DMFT parts.
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The script imports a user-defined DMFT script `dmft_cycle.py` which
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must produce KS density-matrix file `GAMMA` for the next DFT iteration
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and also must return the correlation (including the double counting) energy
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of the impurity model as well as a correlation correction to the
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DFT band energy (resulting from the difference between the bare
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and DMFT density matrices).
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