CHECKPOINT FD

   Warning: Not yet released!

This page contains information about a feature that will be available in a future release of VASP. In other words, currently you cannot use it even with the latest version of VASP. The information may change significantly until it is released.

CHECKPOINT = [string]

Description: CHECKPOINT enables a finite differences calculation to be restarted or split up into displacements

Mind: Available as of VASP 6.6.0

Important: This feature requires HDF5 support.

Mind: This is currently only available for IBRION = 6.

Phonon (or vibrational) modes can be calculated using finite differences. A series of displacements is made, DFT calculations are performed on each of these, and then the second-order force constants are computed and the dynamical matrix constructed, from which the phonon modes and frequencies are calculated. Using CHECKPOINT (with IBRION = 6), it is possible to restart a calculation that crashed from the last displacement, or split the calculation into individual displacements. The displacements are written to the vaspcheckfd.h5 file.

CHECKPOINT = CONTINUE

vaspcheckfd.h5 file is read (if it exists) and the calculation continues where it left off.
Otherwise, vaspcheck.h5 is created and the displacements are written to it. In both cases, the calculation will finish with the complete vaspcheckfd.h5.
Repeating CHECKPOINT = CONTINUE will perform a single SCF at the equilibrium structure and read the displacements from vaspcheckfd.h5.
This mode also detects if the calculation is a single VASP calculation or if it was split into separate pieces. If it has been split, all the calculations need to have finished, or an error will be produced.

CHECKPOINT = RESET - (default): Overwrite the vaspcheckfd.h5 file and start from scratch. The rest is identical to CHECKPOINT = CONTINUE.
CHECKPOINT = LEGACY: Behavior of the code before VASP 6.6.0. No vaspcheckfd.h5 file is written.
CHECKPOINT = PREPARE

The vaspcheckfd.h5 file is created (or overwritten) and filled with metadata.
For each displacement, a CONTCAR_disp-N file is written containing the Nth displacement. VASP then stops after one SCF.
To run this displaced calculation, create a directory disp-N, copy across the corresponding CONTCAR_disp-N file into it and rename it to POSCAR. Then run the calculation with CHECKPOINT = SINGLE.

CHECKPOINT = SINGLE: This mode is used to run the individual single-shot VASP calculations produced by CHECKPOINT = PREPARE. This also produces a vaspcheckfd.h5 file in the corresponding directory that contains the displaced data.

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