Restarting finite differences calculations - Revision history

Huebsch: /* Practical hints */

2026-03-16T11:33:00Z

Practical hints

← Older revision		Revision as of 11:33, 16 March 2026
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	\| \|		\| \|
	-----------------------------------------------------------------------------		-----------------------------------------------------------------------------
	* We recommend using the {{FILE\|CHGCAR}} file from the parent directory of the split calculation for the ~~indiviudal~~ displacements to speed up the calculation. Link this with <code>ln -s ../CHGCAR</code>, ~~making sure to~~ set ~~{{TAG\|LWAVE\|.FALSE.}} and~~ {{TAG\|LCHARG\|.FALSE.}} so that the original ~~wavefunction and~~ charge density ~~are~~ not overwritten. Also set {{TAG\|ICHARG\|1}} ~~in order~~ that the charge density is used, rather than starting from scratch.		* We recommend using the {{FILE\|CHGCAR}} file from the parent directory of the split calculation for the individual displacements to speed up the calculation. Link this with <code>ln -s ../CHGCAR</code>, set {{TAG\|LCHARG\|.FALSE.}} so that the original charge density is not overwritten. Also set {{TAG\|ICHARG\|1}} so that the charge density is used, rather than starting from scratch.

	== Related tags and sections ==		== Related tags and sections ==

Huebsch: /* 2. Single displacement calculations */

2026-03-16T11:31:19Z

2. Single displacement calculations

← Older revision		Revision as of 11:31, 16 March 2026
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	LCHARG = F		LCHARG = F
	""" >> disp-$i/INCAR		""" >> disp-$i/INCAR
	~~cd disp-$i~~		ln -s ../CHGCAR disp-$i/CHGCAR
	ln -s ../CHGCAR
	~~cd ..~~
	done		done
	</syntaxhighlight>		</syntaxhighlight>
Line 197:		Line 195:
	{{TAGBL\|LREAL}} = .FALSE.		{{TAGBL\|LREAL}} = .FALSE.
	{{TAGBL\|LWAVE}} = .FALSE.		{{TAGBL\|LWAVE}} = .FALSE.
	~~{{TAGBL\|LCHARG}} = .FALSE.~~

	# ionic (finite differences)		# ionic (finite differences)
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	{{TAGBL\|NCORE}} = 4		{{TAGBL\|NCORE}} = 4
	{{TAGBL\|ICHARG}} = 1		{{TAGBL\|ICHARG}} = 1
			{{TAGBL\|LCHARG}} = F
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|~~The calculation can optionally be restarted~~ from {{FILE\|WAVECAR}} or {{FILE\|CHGCAR}} files.}}		{{NB\|tip\|It is optional to restart from {{FILE\|WAVECAR}} or {{FILE\|CHGCAR}} files.}}
	In each subdirectory, you can see that a single displacement has been recorded in the '''stdout''':		In each subdirectory, you can see that a single displacement has been recorded in the '''stdout''':

Huebsch: /* 2. Single displacement calculations */

2026-03-16T11:18:10Z

2. Single displacement calculations

← Older revision		Revision as of 11:18, 16 March 2026
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	cp INCAR POTCAR KPOINTS vasp.run disp-$i/		cp INCAR POTCAR KPOINTS vasp.run disp-$i/
	sed -i 's/PREPARE/SINGLE/g' disp-$i/INCAR		sed -i 's/PREPARE/SINGLE/g' disp-$i/INCAR
	echo "NCORE = 4~~" >> disp-$i/INCAR~~		echo """
	~~echo "~~ICHARG = 1" >> disp-$i/INCAR		NCORE = 4
			ICHARG = 1
			LCHARG = F
			""" >> disp-$i/INCAR
	cd disp-$i		cd disp-$i
	ln -s ../CHGCAR		ln -s ../CHGCAR

Huebsch: /* 1. Preparing the displacements */

2026-03-16T11:16:09Z

1. Preparing the displacements

← Older revision		Revision as of 11:16, 16 March 2026
Line 143:		Line 143:
	{{TAGBL\|SIGMA}} = 0.2		{{TAGBL\|SIGMA}} = 0.2
	{{TAGBL\|LREAL}} = .FALSE.		{{TAGBL\|LREAL}} = .FALSE.
			{{TAGBL\|LWAVE}} = .FALSE.

	# ionic (finite differences)		# ionic (finite differences)

Csheldon: /* Practical hints */

2026-03-16T09:17:54Z

Practical hints

← Older revision		Revision as of 09:17, 16 March 2026
Line 272:		Line 272:
	\| \|		\| \|
	-----------------------------------------------------------------------------		-----------------------------------------------------------------------------
	* We recommend using the {{FILE\|CHGCAR}} file from the parent directory of the split calculation for the indiviudal displacements to speed up the calculation. Link this with <code>ln -s ../CHGCAR</code>, making sure to set {{TAG\|LWAVE\|.~~TRUE~~.}} and {{TAG\|LCHARG\|.~~TRUE~~.}} so that the original wavefunction and charge density are not overwritten. Also set {{TAG\|ICHARG\|1}} in order that the charge density is used, rather than starting from scratch.		* We recommend using the {{FILE\|CHGCAR}} file from the parent directory of the split calculation for the indiviudal displacements to speed up the calculation. Link this with <code>ln -s ../CHGCAR</code>, making sure to set {{TAG\|LWAVE\|.FALSE.}} and {{TAG\|LCHARG\|.FALSE.}} so that the original wavefunction and charge density are not overwritten. Also set {{TAG\|ICHARG\|1}} in order that the charge density is used, rather than starting from scratch.

	== Related tags and sections ==		== Related tags and sections ==

Csheldon: /* 2. Single displacement calculations */

2026-03-16T09:17:09Z

2. Single displacement calculations

← Older revision		Revision as of 09:17, 16 March 2026
Line 202:		Line 202:
	{{TAGBL\|ICHARG}} = 1		{{TAGBL\|ICHARG}} = 1
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} ~~file~~ or {{FILE\|CHGCAR}} ~~file~~.}}		{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} or {{FILE\|CHGCAR}} files.}}
	In each subdirectory, you can see that a single displacement has been recorded in the '''stdout''':		In each subdirectory, you can see that a single displacement has been recorded in the '''stdout''':

Csheldon: /* 2. Single displacement calculations */

2026-03-16T09:10:11Z

2. Single displacement calculations

← Older revision		Revision as of 09:10, 16 March 2026
Line 199:		Line 199:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
			{{TAGBL\|NCORE}} = 4
	{{TAGBL\|ICHARG}} = 1		{{TAGBL\|ICHARG}} = 1
	~~{{TAGBL\|NCORE}} = 4~~
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}		{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}

Csheldon: /* 2. Single displacement calculations */

2026-03-16T09:09:58Z

2. Single displacement calculations

← Older revision		Revision as of 09:09, 16 March 2026
Line 194:		Line 194:
	{{TAGBL\|LWAVE}} = .FALSE.		{{TAGBL\|LWAVE}} = .FALSE.
	{{TAGBL\|LCHARG}} = .FALSE.		{{TAGBL\|LCHARG}} = .FALSE.
	~~{{TAGBL\|ICHARG}} = 1~~

	# ionic (finite differences)		# ionic (finite differences)
Line 200:		Line 199:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
			{{TAGBL\|ICHARG}} = 1
	{{TAGBL\|NCORE}} = 4		{{TAGBL\|NCORE}} = 4
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}

Csheldon: /* 2. Single displacement calculations */

2026-03-16T09:09:20Z

2. Single displacement calculations

← Older revision		Revision as of 09:09, 16 March 2026
Line 201:		Line 201:
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
	{{TAGBL\|NCORE}} = 4		{{TAGBL\|NCORE}} = 4

	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}		{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}

Csheldon: /* 2. Single displacement calculations */

2026-03-16T09:08:54Z

2. Single displacement calculations

← Older revision		Revision as of 09:08, 16 March 2026
Line 194:		Line 194:
	{{TAGBL\|LWAVE}} = .FALSE.		{{TAGBL\|LWAVE}} = .FALSE.
	{{TAGBL\|LCHARG}} = .FALSE.		{{TAGBL\|LCHARG}} = .FALSE.
	{{TAGBL\|ICHARG\|1}}		{{TAGBL\|ICHARG}} = 1

	# ionic (finite differences)		# ionic (finite differences)
Line 200:		Line 200:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
	{{TAGBL\|NCORE\|4}}		{{TAGBL\|NCORE}} = 4

	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}

← Older revision		Revision as of 09:10, 16 March 2026
Line 199:		Line 199:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
			{{TAGBL\|NCORE}} = 4
	{{TAGBL\|ICHARG}} = 1		{{TAGBL\|ICHARG}} = 1
	~~{{TAGBL\|NCORE}} = 4~~
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}		{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}

← Older revision		Revision as of 09:09, 16 March 2026
Line 194:		Line 194:
	{{TAGBL\|LWAVE}} = .FALSE.		{{TAGBL\|LWAVE}} = .FALSE.
	{{TAGBL\|LCHARG}} = .FALSE.		{{TAGBL\|LCHARG}} = .FALSE.
	~~{{TAGBL\|ICHARG}} = 1~~

	# ionic (finite differences)		# ionic (finite differences)
Line 200:		Line 199:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
			{{TAGBL\|ICHARG}} = 1
	{{TAGBL\|NCORE}} = 4		{{TAGBL\|NCORE}} = 4
	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}

← Older revision		Revision as of 09:09, 16 March 2026
Line 201:		Line 201:
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
	{{TAGBL\|NCORE}} = 4		{{TAGBL\|NCORE}} = 4

	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}
	{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}		{{NB\|tip\|The calculation can optionally be restarted from {{FILE\|WAVECAR}} file or {{FILE\|CHGCAR}} file.}}

← Older revision		Revision as of 09:08, 16 March 2026
Line 194:		Line 194:
	{{TAGBL\|LWAVE}} = .FALSE.		{{TAGBL\|LWAVE}} = .FALSE.
	{{TAGBL\|LCHARG}} = .FALSE.		{{TAGBL\|LCHARG}} = .FALSE.
	{{TAGBL\|ICHARG\|1}}		{{TAGBL\|ICHARG}} = 1

	# ionic (finite differences)		# ionic (finite differences)
Line 200:		Line 200:
	{{TAGBL\|POTIM}} = 0.015		{{TAGBL\|POTIM}} = 0.015
	{{TAGBL\|CHECKPOINT_FD}} = SINGLE		{{TAGBL\|CHECKPOINT_FD}} = SINGLE
	{{TAGBL\|NCORE\|4}}		{{TAGBL\|NCORE}} = 4

	{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}		{{NB\|important\|You can set different {{TAG\|NCORE}} settings in these calculations, offering parallelization that is not otherwise possible for finite differences.}}