CHECKPOINT FD: Difference between revisions
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{{TAGDEF|CHECKPOINT|[string]}} | {{TAGDEF|CHECKPOINT|[string]}} | ||
Description: {{TAG|CHECKPOINT}} enables a finite | Description: {{TAG|CHECKPOINT}} enables a finite differences calculation to be restarted or split up into displacements | ||
{{Available|6.6.0}} | {{Available|6.6.0}} | ||
{{NB|important|This is currently only available for {{TAG|IBRION|6}}.}} | {{NB|important|This is currently only available for {{TAG|IBRION|6}}.}} | ||
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Phonon (or vibrational) modes can be calculated using [[Phonons from finite differences | finite differences]]. A series of displacements | Phonon (or vibrational) modes can be calculated using [[Phonons from finite differences | finite differences]]. A series of displacements is made, DFT calculations are performed on each of these, and then the second-order force is computed, and the dynamical matrix is constructed, from which the phonon modes and frequencies are calculated. Using {{TAG|CHECKPOINT}} (with {{TAG|IBRION|6}}), it is possible to restart a calculation that crashed from the last displacement. The displacements are written to the {{FILE|vaspcheck.h5}} file. | ||
;{{TAG|CHECKPOINT|CONTINUE}} | ;{{TAG|CHECKPOINT|CONTINUE}} | ||
Revision as of 12:57, 21 January 2026
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.
|
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 is 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 = CONTINUEwill 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