CHECKPOINT FD - Revision history

Huebsch at 14:12, 11 March 2026

2026-03-11T14:12:04Z

← Older revision		Revision as of 14:12, 11 March 2026
Line 1:		Line 1:
	{{DISPLAYTITLE:CHECKPOINT_FD}}		{{DISPLAYTITLE:CHECKPOINT_FD}}
	{{TAGDEF\|CHECKPOINT_FD\|~~[string]~~}}		{{TAGDEF\|CHECKPOINT_FD\| CONTINUE {{!}} RESET {{!}} NONE {{!}} SINGLE \| RESET}}

	Description: Enables a finite differences calculation to be restarted or split up into displacements.		Description: Enables a finite differences calculation to be restarted or split up into displacements.

	----		----

			[[Phonons]] 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.
	{{Available\|6.6.0}}		{{Available\|6.6.0}}
	{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}		{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}
	{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}		{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}
			----
	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_FD\|CONTINUE}} ===		=== {{TAG\|CHECKPOINT_FD\|CONTINUE}} ===
	*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.		:The {{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off. If the {{FILE\|vaspcheckfd.h5}} file is missing, a {{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_FD\|CONTINUE}} will perform a single SCF at the equilibrium structure and read the displacements from {{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}}.		: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.
	*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_FD\|RESET}} (default) ===		=== {{TAG\|CHECKPOINT_FD\|RESET}} (default) ===
	:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.		:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.
	=== {{TAG\|CHECKPOINT_FD\|NONE}} ===		=== {{TAG\|CHECKPOINT_FD\|NONE}} ===
	:~~Behavior of the code before VASP 6.6.0.~~ No {{FILE\|vaspcheckfd.h5}} file is written.		:No {{FILE\|vaspcheckfd.h5}} file is written. This is the behavior of the code before VASP 6.6.0.
	=== {{TAG\|CHECKPOINT_FD\|PREPARE}} ===		=== {{TAG\|CHECKPOINT_FD\|PREPARE}} ===
	*The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata.		:The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata. For each displacement, a {{FILE\|CONTCAR_disp-N}} file is written containing the Nth displacement. The calculation stops after performing one [[electronic minimization]] to obtain the SCF solution of the unperturbed structure.
	*For each displacement, a {{FILE\|CONTCAR_disp-N}} file is written containing the Nth displacement. ~~VASP then~~ stops after one SCF.		:To run the calculation for a specific displacement, create a directory <code>disp-N</code>, copy across the corresponding {{FILE\|CONTCAR_disp-N}} file and rename it to {{FILE\|POSCAR}}. Then, run the calculation with {{TAG\|CHECKPOINT_FD\|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_FD\|SINGLE}} ===		=== {{TAG\|CHECKPOINT_FD\|SINGLE}} ===
	: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.		: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.

Huebsch at 13:56, 11 March 2026

2026-03-11T13:56:44Z

Huebsch at 13:54, 11 March 2026

2026-03-11T13:54:51Z

← Older revision		Revision as of 13:54, 11 March 2026
Line 2:		Line 2:
	{{TAGDEF\|CHECKPOINT_FD\|[string]}}		{{TAGDEF\|CHECKPOINT_FD\|[string]}}

	Description: ~~{{TAG\|CHECKPOINT_FD}} enables~~ a finite differences calculation to be restarted or split up into displacements		Description: Enables a finite differences calculation to be restarted or split up into displacements.

			----
	{{Available\|6.6.0}}		{{Available\|6.6.0}}
	{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}		{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}
	{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}		{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}

	~~----~~

	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.		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.
Line 28:		Line 28:

	==Related tags and articles==		==Related tags and articles==
	[[~~phonons~~ from finite differences]], [[Restarting finite differences calculations]], {{TAG\|IBRION}}, {{FILE\|vaspcheckfd.h5}}, {{FILE\|CONTCAR_disp-N}}		[[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}}		{{sc\|CHECKPOINT_FD\|HowTo\|Workflows that use this tag}}
	[[Category:INCAR tag]][[Category:Phonons~~]][[Category:Electron-phonon interactions~~]]		[[Category:INCAR tag]][[Category:Phonons]]

Csheldon: Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD over redirect

2026-03-04T15:07:00Z

Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD over redirect

← Older revision	Revision as of 15:07, 4 March 2026
(No difference)

Csheldon: Csheldon moved page CHECKPOINT FD to Construction:CHECKPOINT FD over redirect

2026-03-04T10:14:59Z

Csheldon moved page CHECKPOINT FD to Construction:CHECKPOINT FD over redirect

← Older revision	Revision as of 10:14, 4 March 2026
(No difference)

Csheldon: Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD over redirect

2026-03-04T10:13:40Z

Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD over redirect

← Older revision	Revision as of 10:13, 4 March 2026
(No difference)

Csheldon: Csheldon moved page CHECKPOINT FD to Construction:CHECKPOINT FD over redirect

2026-02-20T08:02:44Z

Csheldon moved page CHECKPOINT FD to Construction:CHECKPOINT FD over redirect

← Older revision	Revision as of 08:02, 20 February 2026
(No difference)

Csheldon at 11:34, 19 February 2026

2026-02-19T11:34:58Z

← Older revision		Revision as of 11:34, 19 February 2026
Line 31:		Line 31:

	{{sc\|NSW\|Examples\|Examples that use this tag}}		{{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]]

Csheldon at 11:34, 19 February 2026

2026-02-19T11:34:23Z

← Older revision		Revision as of 11:34, 19 February 2026
Line 13:		Line 13:
	;{{TAG\|CHECKPOINT_FD\|CONTINUE}}		;{{TAG\|CHECKPOINT_FD\|CONTINUE}}
	*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.		*{{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_FD\|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.		*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.

Csheldon: Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD

2026-02-19T11:02:29Z

Csheldon moved page Construction:CHECKPOINT FD to CHECKPOINT FD

← Older revision	Revision as of 11:02, 19 February 2026
(No difference)

← Older revision		Revision as of 14:12, 11 March 2026
Line 1:		Line 1:
	{{DISPLAYTITLE:CHECKPOINT_FD}}		{{DISPLAYTITLE:CHECKPOINT_FD}}
	{{TAGDEF\|CHECKPOINT_FD\|~~[string]~~}}		{{TAGDEF\|CHECKPOINT_FD\| CONTINUE {{!}} RESET {{!}} NONE {{!}} SINGLE \| RESET}}

	Description: Enables a finite differences calculation to be restarted or split up into displacements.		Description: Enables a finite differences calculation to be restarted or split up into displacements.

	----		----

			[[Phonons]] 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.
	{{Available\|6.6.0}}		{{Available\|6.6.0}}
	{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}		{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}
	{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}		{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}
			----
	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_FD\|CONTINUE}} ===		=== {{TAG\|CHECKPOINT_FD\|CONTINUE}} ===
	*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.		:The {{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off. If the {{FILE\|vaspcheckfd.h5}} file is missing, a {{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_FD\|CONTINUE}} will perform a single SCF at the equilibrium structure and read the displacements from {{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}}.		: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.
	*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_FD\|RESET}} (default) ===		=== {{TAG\|CHECKPOINT_FD\|RESET}} (default) ===
	:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.		:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.
	=== {{TAG\|CHECKPOINT_FD\|NONE}} ===		=== {{TAG\|CHECKPOINT_FD\|NONE}} ===
	:~~Behavior of the code before VASP 6.6.0.~~ No {{FILE\|vaspcheckfd.h5}} file is written.		:No {{FILE\|vaspcheckfd.h5}} file is written. This is the behavior of the code before VASP 6.6.0.
	=== {{TAG\|CHECKPOINT_FD\|PREPARE}} ===		=== {{TAG\|CHECKPOINT_FD\|PREPARE}} ===
	*The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata.		:The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata. For each displacement, a {{FILE\|CONTCAR_disp-N}} file is written containing the Nth displacement. The calculation stops after performing one [[electronic minimization]] to obtain the SCF solution of the unperturbed structure.
	*For each displacement, a {{FILE\|CONTCAR_disp-N}} file is written containing the Nth displacement. ~~VASP then~~ stops after one SCF.		:To run the calculation for a specific displacement, create a directory <code>disp-N</code>, copy across the corresponding {{FILE\|CONTCAR_disp-N}} file and rename it to {{FILE\|POSCAR}}. Then, run the calculation with {{TAG\|CHECKPOINT_FD\|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_FD\|SINGLE}} ===		=== {{TAG\|CHECKPOINT_FD\|SINGLE}} ===
	: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.		: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.

← Older revision		Revision as of 13:54, 11 March 2026
Line 2:		Line 2:
	{{TAGDEF\|CHECKPOINT_FD\|[string]}}		{{TAGDEF\|CHECKPOINT_FD\|[string]}}

	Description: ~~{{TAG\|CHECKPOINT_FD}} enables~~ a finite differences calculation to be restarted or split up into displacements		Description: Enables a finite differences calculation to be restarted or split up into displacements.

			----
	{{Available\|6.6.0}}		{{Available\|6.6.0}}
	{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}		{{NB\|important\|This feature requires [[:Category:HDF5_support \| HDF5 support]].}}
	{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}		{{NB\|mind\|This is currently only available for {{TAG\|IBRION\|6}}.}}

	~~----~~

	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.		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.
Line 28:		Line 28:

	==Related tags and articles==		==Related tags and articles==
	[[~~phonons~~ from finite differences]], [[Restarting finite differences calculations]], {{TAG\|IBRION}}, {{FILE\|vaspcheckfd.h5}}, {{FILE\|CONTCAR_disp-N}}		[[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}}		{{sc\|CHECKPOINT_FD\|HowTo\|Workflows that use this tag}}
	[[Category:INCAR tag]][[Category:Phonons~~]][[Category:Electron-phonon interactions~~]]		[[Category:INCAR tag]][[Category:Phonons]]

← Older revision		Revision as of 11:34, 19 February 2026
Line 13:		Line 13:
	;{{TAG\|CHECKPOINT_FD\|CONTINUE}}		;{{TAG\|CHECKPOINT_FD\|CONTINUE}}
	*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.		*{{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_FD\|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.		*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.

← Older revision		Revision as of 13:56, 11 March 2026
Line 11:		Line 11:
	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.		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_FD\|CONTINUE}}		=== {{TAG\|CHECKPOINT_FD\|CONTINUE}} ===
	*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.		*{{FILE\|vaspcheckfd.h5}} file is read (if it exists) and the calculation continues where it left off.
	*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}}.		*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_FD\|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.		*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_FD\|RESET}} - (default)		=== {{TAG\|CHECKPOINT_FD\|RESET}} (default) ===
	:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.		:Overwrite the {{FILE\|vaspcheckfd.h5}} file and start from scratch. The rest is identical to {{TAG\|CHECKPOINT_FD\|CONTINUE}}.
	;{{TAG\|CHECKPOINT_FD\|NONE}}		=== {{TAG\|CHECKPOINT_FD\|NONE}} ===
	:Behavior of the code before VASP 6.6.0. No {{FILE\|vaspcheckfd.h5}} file is written.		:Behavior of the code before VASP 6.6.0. No {{FILE\|vaspcheckfd.h5}} file is written.
	;{{TAG\|CHECKPOINT_FD\|PREPARE}}		=== {{TAG\|CHECKPOINT_FD\|PREPARE}} ===
	*The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata.		*The {{FILE\|vaspcheckfd.h5}} file is created (or overwritten) and filled with metadata.
	*For each displacement, a {{FILE\|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 {{FILE\|CONTCAR_disp-N}} file into it and rename it to {{FILE\|POSCAR}}. Then run the calculation with {{TAG\|CHECKPOINT_FD\|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_FD\|SINGLE}}		=== {{TAG\|CHECKPOINT_FD\|SINGLE}} ===
	: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.		: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.