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 is currently only available for IBRION = 6.

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Phonon (or vibrational) modes can be calculated using finite differences. A series of displacements are made, DFT calculations performed on each of these, and then the second-order force computed and the dynamical matrix is 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. The displacements are written to the vaspcheck.h5 file.

CHECKPOINT = CONTINUE

• vaspcheck.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 vaspcheck.h5.
• Repeating CHECKPOINT = CONTINUE will perform a single SCF at the equilibrium structure and read the displacements from vaspcheck.h5.
• This mode also detects if the calculation is a single VASP calculation or if it was split into separate pieces. If it was split, all the calculations need to have finished or an error is produced.

CHECKPOINT = RESET - (default)

Overwrite the vaspcheck.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 vaspcheck.h5 file is written.

CHECKPOINT = PREPARE

• The vaspcheck.h5 file is created (or overwritten) and filled with meta data.
• 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 vaspcheck.h5 file in the corresponding directory that contains the displaced data.

Related tags and articles

structure optimization, phonons from finite differences, IBRION Examples that use this tag