PREC - Revision history

Huebsch at 11:57, 17 October 2024

2024-10-17T11:57:25Z

← Older revision		Revision as of 11:57, 17 October 2024
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	{{sc\|PREC\|Examples\|Examples that use this tag}}		{{sc\|PREC\|Examples\|Examples that use this tag}}
	~~----~~

	[[Category:INCAR tag]][[Category:~~Electronic minimization~~]][[Category:Memory]]		[[Category:INCAR tag]][[Category:Projector-augmented-wave method]][[Category:Memory]]

Ftran at 10:00, 31 October 2023

2023-10-31T10:00:29Z

Show changes

Schlipf at 12:31, 14 June 2023

2023-06-14T12:31:05Z

← Older revision		Revision as of 12:31, 14 June 2023
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	\| Single (VASP.6) \|\|align="center"\|max({{TAG\|ENMAX}}) \|\| 2 ×G<sub>cut</sub> \|\|align="center"\|{{TAG\|NGX}} \|\|-5×10<sup>-4</sup>		\| Single (VASP.6) \|\|align="center"\|max({{TAG\|ENMAX}}) \|\| 2 ×G<sub>cut</sub> \|\|align="center"\|{{TAG\|NGX}} \|\|-5×10<sup>-4</sup>
	\|-		\|-
	\|SingleN (VASP.6 ~~development~~)		\|SingleN (VASP.6)
	\|align="center"\|max({{TAG\|ENMAX}})		\|align="center"\|max({{TAG\|ENMAX}})
	\|3/2×G<sub>cut</sub>		\|3/2×G<sub>cut</sub>

Huebsch at 09:04, 25 May 2022

2022-05-25T09:04:04Z

← Older revision		Revision as of 09:04, 25 May 2022
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	----		----

	[[Category:INCAR tag]][[Category:Electronic minimization]]		[[Category:INCAR tag]][[Category:Electronic minimization]][[Category:Memory]]

Huebsch at 15:28, 6 April 2022

2022-04-06T15:28:06Z

← Older revision		Revision as of 15:28, 6 April 2022
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	Description: {{TAG\|PREC}} specifies the "precision"-mode.		Description: {{TAG\|PREC}} specifies the "precision"-mode.
	----		----
	We recommend ~~to use~~ {{TAG\|PREC}}=Normal or {{TAG\|PREC}}=Accurate.		We recommend using {{TAG\|PREC}}=Normal or {{TAG\|PREC}}=Accurate.
	The settings {{TAG\|PREC}}=Medium and {{TAG\|PREC}}=High (available already in VASP.4.4)		The settings {{TAG\|PREC}}=Medium and {{TAG\|PREC}}=High (available already in VASP.4.4)
	are no longer recommended. {{TAG\|PREC}}=Normal can be used for most		are no longer recommended. {{TAG\|PREC}}=Normal can be used for most
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	this really helps).		this really helps).

	The use of {{TAG\|PREC}}=High is no longer ~~recommend~~ (and is only available for compatibility). Essentially {{TAG\|PREC}}=High only increases the energy cutoff		The use of {{TAG\|PREC}}=High is no longer recommended (and is only available for compatibility). Essentially {{TAG\|PREC}}=High only increases the energy cutoff
	by 30 %. The same effect can be achieved by just manually increasing {{TAG\|ENCUT}}		by 30 %. The same effect can be achieved by just manually increasing {{TAG\|ENCUT}}
	in the INCAR file. If, additionally, very accurate forces are required, {{TAG\|PREC}}=Accurate can be used in combination with an increased energy cutoff.		in the INCAR file. If, additionally, very accurate forces are required, {{TAG\|PREC}}=Accurate can be used in combination with an increased energy cutoff.

	'''Mind''': we recommend ~~to specify~~ the energy cutoff ({{TAG\|ENCUT}}) always manually in the {{FILE\|INCAR}} file, to avoid incompatibilities between calculations.		'''Mind''': we recommend specifying the energy cutoff ({{TAG\|ENCUT}}) always manually in the {{FILE\|INCAR}} file, to avoid incompatibilities between calculations.
	----		----
	The {{TAG\|PREC}} parameter sets the defaults for four sets of parameters ({{TAG\|ENCUT}}; {{TAG\|NGX}}, {{TAG\|NGY}}, {{TAG\|NGZ}}; {{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}, and {{TAG\|ROPT}}):		The {{TAG\|PREC}} parameter sets the defaults for four sets of parameters ({{TAG\|ENCUT}}; {{TAG\|NGX}}, {{TAG\|NGY}}, {{TAG\|NGZ}}; {{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}, and {{TAG\|ROPT}}):
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	:In addition, the {{TAG\|PREC}} tag determines the spacing for the grids representing the augmentation charges, charge densities and potentials ({{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}). For {{TAG\|PREC}}=Accurate and {{TAG\|PREC}}=Normal, the support grid contains twice as many points in each direction as the grids for the orbitals ({{TAG\|NGXF}}=2×{{TAG\|NGX}}, {{TAG\|NGYF}}=2×{{TAG\|NGY}}, {{TAG\|NGZF}}=2×{{TAG\|NGZ}}). In all other cases, {{TAG\|NGXF}}, {{TAG\|NGYF}}, and {{TAG\|NGZF}} are determined by some heuristic formula from {{TAG\|ENAUG}} (these settings should be avoided).		:In addition, the {{TAG\|PREC}} tag determines the spacing for the grids representing the augmentation charges, charge densities and potentials ({{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}). For {{TAG\|PREC}}=Accurate and {{TAG\|PREC}}=Normal, the support grid contains twice as many points in each direction as the grids for the orbitals ({{TAG\|NGXF}}=2×{{TAG\|NGX}}, {{TAG\|NGYF}}=2×{{TAG\|NGY}}, {{TAG\|NGZF}}=2×{{TAG\|NGZ}}). In all other cases, {{TAG\|NGXF}}, {{TAG\|NGYF}}, and {{TAG\|NGZF}} are determined by some heuristic formula from {{TAG\|ENAUG}} (these settings should be avoided).

	:{{TAG\|PREC}}=Single is uses the same FFT grids as {{TAG\|PREC}}=Normal in VASP.5 and the same FFT grids as {{TAG\|PREC}}=Accurate in VASP.6. The double grid technique is not used. This is convenient, if one needs to cut down on storage demands, or if one wants to reduce the size of the files {{FILE\|CHG}} and {{FILE\|CHGCAR}}. Furthermore, {{TAG\|PREC}}=Single avoids high frequency oscillations caused the double grid technique and the resulting Fourier interpolation. It is often expedient for scanning tunneling simulations or other calculations where high frequency wiggles of the charge density in the vacuum region are undesirable.		:{{TAG\|PREC}}=Single uses the same FFT grids as {{TAG\|PREC}}=Normal in VASP.5 and the same FFT grids as {{TAG\|PREC}}=Accurate in VASP.6. The double grid technique is not used. This is convenient, if one needs to cut down on storage demands, or if one wants to reduce the size of the files {{FILE\|CHG}} and {{FILE\|CHGCAR}}. Furthermore, {{TAG\|PREC}}=Single avoids high-frequency oscillations caused by the double-grid technique and the resulting Fourier interpolation. It is often expedient for scanning tunneling simulations or other calculations where high-frequency wiggles of the charge density in the vacuum region are undesirable.

	*Real space projectors ({{TAG\|ROPT}}):		*Real space projectors ({{TAG\|ROPT}}):
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	\|}		\|}

	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|NGX}},		{{TAG\|NGX}},
	{{TAG\|NGY}},		{{TAG\|NGY}},
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	----		----

	[[Category:INCAR]][[Category:Electronic ~~Minimization]][[Category:Electronic Minimization Methods~~]]		[[Category:INCAR tag]][[Category:Electronic minimization]]

Vaspmaster at 13:46, 8 November 2021

2021-11-08T13:46:36Z

← Older revision		Revision as of 13:46, 8 November 2021
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	\|-		\|-
	\|SingleN (VASP.6 development)		\|SingleN (VASP.6 development)
	\|max({{TAG\|ENMAX}})		\|align="center"\|max({{TAG\|ENMAX}})
	\|3/2×G<sub>cut</sub>		\|3/2×G<sub>cut</sub>
	\|{{TAG\|NGX}}		\|align="center"\|{{TAG\|NGX}}
	\| -5×10<sup>-4</sup>		\| -5×10<sup>-4</sup>
	\|-		\|-

Vaspmaster at 13:45, 8 November 2021

2021-11-08T13:45:37Z

← Older revision		Revision as of 13:45, 8 November 2021
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	\| Accurate \|\|align="center"\|max({{TAG\|ENMAX}}) \|\|align="center"\|2×G<sub>cut</sub> \|\|align="center"\|2×{{TAG\|NGX}}\|\|-2.5×10<sup>-4</sup>		\| Accurate \|\|align="center"\|max({{TAG\|ENMAX}}) \|\|align="center"\|2×G<sub>cut</sub> \|\|align="center"\|2×{{TAG\|NGX}}\|\|-2.5×10<sup>-4</sup>
	\|-		\|-
	\| '''old settings:'''		\| colspan="5" \| '''old settings:'''
	\|-		\|-
	\| Low \|\|align="center"\|max({{TAG\|ENMIN}}) \|\| 3/2×G<sub>cut</sub> \|\|align="center"\|3×G<sub>aug</sub> \|\|-1×10<sup>-2</sup>		\| Low \|\|align="center"\|max({{TAG\|ENMIN}}) \|\| 3/2×G<sub>cut</sub> \|\|align="center"\|3×G<sub>aug</sub> \|\|-1×10<sup>-2</sup>

Kresse: Added description of SingleN

2021-03-26T06:50:56Z

Added description of SingleN

← Older revision		Revision as of 06:50, 26 March 2021
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	\|-		\|-
	\| Single (VASP.6) \|\|align="center"\|max({{TAG\|ENMAX}}) \|\| 2 ×G<sub>cut</sub> \|\|align="center"\|{{TAG\|NGX}} \|\|-5×10<sup>-4</sup>		\| Single (VASP.6) \|\|align="center"\|max({{TAG\|ENMAX}}) \|\| 2 ×G<sub>cut</sub> \|\|align="center"\|{{TAG\|NGX}} \|\|-5×10<sup>-4</sup>
			\|-
			\|SingleN (VASP.6 development)
			\|max({{TAG\|ENMAX}})
			\|3/2×G<sub>cut</sub>
			\|{{TAG\|NGX}}
			\| -5×10<sup>-4</sup>
	\|-		\|-
	\| Accurate \|\|align="center"\|max({{TAG\|ENMAX}}) \|\|align="center"\|2×G<sub>cut</sub> \|\|align="center"\|2×{{TAG\|NGX}}\|\|-2.5×10<sup>-4</sup>		\| Accurate \|\|align="center"\|max({{TAG\|ENMAX}}) \|\|align="center"\|2×G<sub>cut</sub> \|\|align="center"\|2×{{TAG\|NGX}}\|\|-2.5×10<sup>-4</sup>
	\|-		\|-
	\| old settings:		\| '''old settings:'''
	\|-		\|-
	\| Low \|\|align="center"\|max({{TAG\|ENMIN}}) \|\| 3/2×G<sub>cut</sub> \|\|align="center"\|3×G<sub>aug</sub> \|\|-1×10<sup>-2</sup>		\| Low \|\|align="center"\|max({{TAG\|ENMIN}}) \|\| 3/2×G<sub>cut</sub> \|\|align="center"\|3×G<sub>aug</sub> \|\|-1×10<sup>-2</sup>

Karsai: /* Related Tags and Sections */

2019-04-19T10:41:45Z

Related Tags and Sections

← Older revision		Revision as of 10:41, 19 April 2019
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	{{sc\|PREC\|Examples\|Examples that use this tag}}		{{sc\|PREC\|Examples\|Examples that use this tag}}
	----		----
	~~[[The_VASP_Manual\|Contents]]~~

	[[Category:INCAR]][[Category:Electronic Minimization]][[Category:Electronic Minimization Methods]]		[[Category:INCAR]][[Category:Electronic Minimization]][[Category:Electronic Minimization Methods]]

Karsai at 17:43, 3 March 2019

2019-03-03T17:43:45Z

← Older revision		Revision as of 17:43, 3 March 2019
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	[[The_VASP_Manual\|Contents]]		[[The_VASP_Manual\|Contents]]

	[[Category:INCAR]]		[[Category:INCAR]][[Category:Electronic Minimization]][[Category:Electronic Minimization Methods]]

← Older revision		Revision as of 15:28, 6 April 2022
Line 4:		Line 4:
	Description: {{TAG\|PREC}} specifies the "precision"-mode.		Description: {{TAG\|PREC}} specifies the "precision"-mode.
	----		----
	We recommend ~~to use~~ {{TAG\|PREC}}=Normal or {{TAG\|PREC}}=Accurate.		We recommend using {{TAG\|PREC}}=Normal or {{TAG\|PREC}}=Accurate.
	The settings {{TAG\|PREC}}=Medium and {{TAG\|PREC}}=High (available already in VASP.4.4)		The settings {{TAG\|PREC}}=Medium and {{TAG\|PREC}}=High (available already in VASP.4.4)
	are no longer recommended. {{TAG\|PREC}}=Normal can be used for most		are no longer recommended. {{TAG\|PREC}}=Normal can be used for most
Line 12:		Line 12:
	this really helps).		this really helps).

	The use of {{TAG\|PREC}}=High is no longer ~~recommend~~ (and is only available for compatibility). Essentially {{TAG\|PREC}}=High only increases the energy cutoff		The use of {{TAG\|PREC}}=High is no longer recommended (and is only available for compatibility). Essentially {{TAG\|PREC}}=High only increases the energy cutoff
	by 30 %. The same effect can be achieved by just manually increasing {{TAG\|ENCUT}}		by 30 %. The same effect can be achieved by just manually increasing {{TAG\|ENCUT}}
	in the INCAR file. If, additionally, very accurate forces are required, {{TAG\|PREC}}=Accurate can be used in combination with an increased energy cutoff.		in the INCAR file. If, additionally, very accurate forces are required, {{TAG\|PREC}}=Accurate can be used in combination with an increased energy cutoff.

	'''Mind''': we recommend ~~to specify~~ the energy cutoff ({{TAG\|ENCUT}}) always manually in the {{FILE\|INCAR}} file, to avoid incompatibilities between calculations.		'''Mind''': we recommend specifying the energy cutoff ({{TAG\|ENCUT}}) always manually in the {{FILE\|INCAR}} file, to avoid incompatibilities between calculations.
	----		----
	The {{TAG\|PREC}} parameter sets the defaults for four sets of parameters ({{TAG\|ENCUT}}; {{TAG\|NGX}}, {{TAG\|NGY}}, {{TAG\|NGZ}}; {{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}, and {{TAG\|ROPT}}):		The {{TAG\|PREC}} parameter sets the defaults for four sets of parameters ({{TAG\|ENCUT}}; {{TAG\|NGX}}, {{TAG\|NGY}}, {{TAG\|NGZ}}; {{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}, and {{TAG\|ROPT}}):
Line 59:		Line 59:
	:In addition, the {{TAG\|PREC}} tag determines the spacing for the grids representing the augmentation charges, charge densities and potentials ({{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}). For {{TAG\|PREC}}=Accurate and {{TAG\|PREC}}=Normal, the support grid contains twice as many points in each direction as the grids for the orbitals ({{TAG\|NGXF}}=2×{{TAG\|NGX}}, {{TAG\|NGYF}}=2×{{TAG\|NGY}}, {{TAG\|NGZF}}=2×{{TAG\|NGZ}}). In all other cases, {{TAG\|NGXF}}, {{TAG\|NGYF}}, and {{TAG\|NGZF}} are determined by some heuristic formula from {{TAG\|ENAUG}} (these settings should be avoided).		:In addition, the {{TAG\|PREC}} tag determines the spacing for the grids representing the augmentation charges, charge densities and potentials ({{TAG\|NGXF}}, {{TAG\|NGYF}}, {{TAG\|NGZF}}). For {{TAG\|PREC}}=Accurate and {{TAG\|PREC}}=Normal, the support grid contains twice as many points in each direction as the grids for the orbitals ({{TAG\|NGXF}}=2×{{TAG\|NGX}}, {{TAG\|NGYF}}=2×{{TAG\|NGY}}, {{TAG\|NGZF}}=2×{{TAG\|NGZ}}). In all other cases, {{TAG\|NGXF}}, {{TAG\|NGYF}}, and {{TAG\|NGZF}} are determined by some heuristic formula from {{TAG\|ENAUG}} (these settings should be avoided).

	:{{TAG\|PREC}}=Single is uses the same FFT grids as {{TAG\|PREC}}=Normal in VASP.5 and the same FFT grids as {{TAG\|PREC}}=Accurate in VASP.6. The double grid technique is not used. This is convenient, if one needs to cut down on storage demands, or if one wants to reduce the size of the files {{FILE\|CHG}} and {{FILE\|CHGCAR}}. Furthermore, {{TAG\|PREC}}=Single avoids high frequency oscillations caused the double grid technique and the resulting Fourier interpolation. It is often expedient for scanning tunneling simulations or other calculations where high frequency wiggles of the charge density in the vacuum region are undesirable.		:{{TAG\|PREC}}=Single uses the same FFT grids as {{TAG\|PREC}}=Normal in VASP.5 and the same FFT grids as {{TAG\|PREC}}=Accurate in VASP.6. The double grid technique is not used. This is convenient, if one needs to cut down on storage demands, or if one wants to reduce the size of the files {{FILE\|CHG}} and {{FILE\|CHGCAR}}. Furthermore, {{TAG\|PREC}}=Single avoids high-frequency oscillations caused by the double-grid technique and the resulting Fourier interpolation. It is often expedient for scanning tunneling simulations or other calculations where high-frequency wiggles of the charge density in the vacuum region are undesirable.

	*Real space projectors ({{TAG\|ROPT}}):		*Real space projectors ({{TAG\|ROPT}}):
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	\|}		\|}

	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|NGX}},		{{TAG\|NGX}},
	{{TAG\|NGY}},		{{TAG\|NGY}},
Line 96:		Line 96:
	----		----

	[[Category:INCAR]][[Category:Electronic ~~Minimization]][[Category:Electronic Minimization Methods~~]]		[[Category:INCAR tag]][[Category:Electronic minimization]]