CHECKPOINT FD: Difference between revisions

Latest revision as of 15:07, 4 March 2026

Description: CHECKPOINT_FD 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_FD (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_FD = CONTINUE

vaspcheckfd.h5 file is read (if it exists) and the calculation continues where it left off.
Otherwise, vaspcheckfd.h5 is created and the displacements are written to it. In both cases, the calculation will finish with the complete vaspcheckfd.h5.
Repeating CHECKPOINT_FD = 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_FD = RESET - (default): Overwrite the vaspcheckfd.h5 file and start from scratch. The rest is identical to CHECKPOINT_FD = CONTINUE.
CHECKPOINT_FD = NONE: Behavior of the code before VASP 6.6.0. No vaspcheckfd.h5 file is written.
CHECKPOINT_FD = 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_FD = SINGLE.

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

@@ Line 1: / Line 1: @@
-{{DISPLAYTITLE:CHECKPOINT}}
+{{DISPLAYTITLE:CHECKPOINT_FD}}
-{{not released}}
+{{TAGDEF|CHECKPOINT_FD|[string]}}
-{{TAGDEF|CHECKPOINT|[string]}}
-Description: {{TAG|CHECKPOINT}} enables a finite differences calculation to be restarted or split up into displacements
+Description: {{TAG|CHECKPOINT_FD}} enables a finite differences calculation to be restarted or split up into displacements
 {{Available|6.6.0}}
 {{NB|important|This feature requires [[:Category:HDF5_support | HDF5 support]].}}
@@ Line 10: / Line 9: @@
 ----
-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 [[Construction:Restarting_finite_differences_calculations#Restarting_a_finite_difference_calculation | restart a calculation that crashed]] from the last displacement, or [[Construction:Restarting_finite_differences_calculations#Splitting_a_finite_difference_calculation | split the calculation into individual displacements]]. The displacements are written to the {{FILE|vaspcheckfd.h5}} file.
+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 constants are computed and the dynamical matrix constructed, from which the phonon modes and frequencies are calculated. Using {{TAG|CHECKPOINT_FD}} (with {{TAG|IBRION|6}}), it is possible to [[Construction:Restarting_finite_differences_calculations#Restarting_a_finite_difference_calculation | restart a calculation that crashed]] from the last displacement, or [[Construction:Restarting_finite_differences_calculations#Splitting_a_finite_difference_calculation | split the calculation into individual displacements]]. The displacements are written to the {{FILE|vaspcheckfd.h5}} file.
-;{{TAG|CHECKPOINT|CONTINUE}}
+;{{TAG|CHECKPOINT_FD|CONTINUE}}
 *{{FILE|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.
-*Otherwise, {{FILE|vaspcheck.h5}} is created and the displacements are written to it. In both cases, the calculation will finish with the complete {{FILE|vaspcheckfd.h5}}.
+*Otherwise, {{FILE|vaspcheckfd.h5}} is created and the displacements are written to it. In both cases, the calculation will finish with the complete {{FILE|vaspcheckfd.h5}}.
-*Repeating {{TAG|CHECKPOINT|CONTINUE}} will perform a single SCF at the equilibrium structure and read the displacements from {{FILE|vaspcheckfd.h5}}.
+*Repeating {{TAG|CHECKPOINT_FD|CONTINUE}} will perform a single SCF at the equilibrium structure and read the displacements from {{FILE|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.
-;{{TAG|CHECKPOINT|RESET}} - (default)
+;{{TAG|CHECKPOINT_FD|RESET}} - (default)
-:Overwrite the {{FILE|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG|CHECKPOINT|CONTINUE}}.
+:Overwrite the {{FILE|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG|CHECKPOINT_FD|CONTINUE}}.
-;{{TAG|CHECKPOINT|LEGACY}}
+;{{TAG|CHECKPOINT_FD|NONE}}
 :Behavior of the code before VASP 6.6.0. No {{FILE|vaspcheckfd.h5}} file is written.
-;{{TAG|CHECKPOINT|PREPARE}}
+;{{TAG|CHECKPOINT_FD|PREPARE}}
 *The {{FILE|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.
+*For each displacement, a {{FILE|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 {{FILE|POSCAR}}. Then run the calculation with {{TAG|CHECKPOINT|SINGLE}}.
+*To run this displaced calculation, create a directory ''disp-N'', copy across the corresponding {{FILE|CONTCAR_disp-N}} file into it and rename it to {{FILE|POSCAR}}. Then run the calculation with {{TAG|CHECKPOINT_FD|SINGLE}}.
-;{{TAG|CHECKPOINT|SINGLE}}
+;{{TAG|CHECKPOINT_FD|SINGLE}}
-:This mode is used to run the individual single-shot VASP calculations produced by {{TAG|CHECKPOINT|PREPARE}}. This also produces a {{FILE|vaspcheckfd.h5}} file in the corresponding directory that contains the displaced data.
+:This mode is used to run the individual single-shot VASP calculations produced by {{TAG|CHECKPOINT_FD|PREPARE}}. This also produces a {{FILE|vaspcheckfd.h5}} file in the corresponding directory that contains the displaced data.
 ==Related tags and articles==
-[[structure optimization]], [[phonons from finite differences]], {{TAG|IBRION}}
+[[phonons from finite differences]], [[Restarting finite differences calculations]], {{TAG|IBRION}}, {{FILE|vaspcheckfd.h5}}, {{FILE|CONTCAR_disp-N}}
 {{sc|NSW|Examples|Examples that use this tag}}
-<!--[[Category:INCAR tag]][[Category:Phonons]][[Category:Electron-phonon interactions]]-->
+[[Category:INCAR tag]][[Category:Phonons]][[Category:Electron-phonon interactions]]