KERNEL TRUNCATION/FACTOR - Revision history

Huebsch at 11:25, 17 March 2026

2026-03-17T11:25:42Z

← Older revision		Revision as of 11:25, 17 March 2026
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	{{TAG\|KERNEL_TRUNCATION/IPAD}},		{{TAG\|KERNEL_TRUNCATION/IPAD}},
	{{TAG\|KERNEL_TRUNCATION/ISURFACE}}		{{TAG\|KERNEL_TRUNCATION/ISURFACE}}

	~~== References ==~~

	[[Category:INCAR tag]]		[[Category:INCAR tag]]
	[[Category:Electrostatics]]		[[Category:Electrostatics]]

Huebsch at 11:25, 17 March 2026

2026-03-17T11:25:29Z

← Older revision		Revision as of 11:25, 17 March 2026
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	{{TAGDEF\|KERNEL_TRUNCATION/FACTOR\| real}}		{{TAGDEF\|KERNEL_TRUNCATION/FACTOR\| real}}
	{{DEF\|KERNEL_TRUNCATION/FACTOR\|$\sqrt{3}$\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|0}}\|1\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|2}}}}		{{DEF\|KERNEL_TRUNCATION/FACTOR\|$\sqrt{3}$\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|0}}\|1\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|2}}}}
			{{DISPLAYTITLE:KERNEL_TRUNCATION/FACTOR}}
	'''Description:'''		'''Description:'''
	~~{{TAG\|KERNEL_TRUNCATION/FACTOR}} determines~~ the spatial extent of the truncated Coulomb interaction relative to the ~~full~~ cell dimension along the truncation direction~~{{cite\|vijay:prb:2025}}~~.		Determines the spatial extent of the truncated Coulomb interaction relative to the computational cell dimension along the truncation direction.

	----		----

	~~This tag~~ defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).		{{TAG\|KERNEL_TRUNCATION/FACTOR}} defines the cutoff distance of the Coulomb-kernel-truncation boundary. It is expressed as a fraction of the simulation-cell length along the truncated axis (e.g., the surface normal for 2D systems {{TAG\|ISURFACE}}).
	{{NB\|mind\|		{{NB\|mind\|
	*{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} ~~must be set to <code>.TRUE.</code> for~~ {{TAG\|KERNEL_TRUNCATION/FACTOR}} ~~to take effect~~.		*If{{TAG\|KERNEL_TRUNCATION/LTRUNCATE\|F}}, {{TAG\|KERNEL_TRUNCATION/FACTOR}} is ignored.
	*~~This tag is only available~~ as of VASP.6.5.0.}}		*Available as of VASP.6.5.0.}}
	{{NB\|warning\|When padding is used, the vaccum is added on the edges of the cell, as such it is very important that the motif is centered in the simulation box. If you encounter problems using Coulomb truncation with padding, try the same calculations without padding (see examples bellow).}}
	~~== Example ==~~

	~~<pre>~~
	~~KERNEL_TRUNCATION {~~
	~~LTRUNCATE = T~~
	~~IDIMENSIONALITY = 2~~
	~~ISURFACE = 3~~
	~~IPAD = 2~~
	~~FACTOR = 1~~
	}
	~~</pre>~~
	~~In this case an additional empty cell is added along the z direciton as padding. The coulomb interaction is truncated beyond a z length. This ensures maximum usage of the simulation box.~~

	~~<pre>~~
	~~KERNEL_TRUNCATION {~~
	~~LTRUNCATE = T~~
	~~IDIMENSIONALITY = 2~~
	~~ISURFACE = 3~~
	~~IPAD = 1~~
	~~FACTOR = 0.5~~
	}
	~~</pre>~~

	This setup corresponds to truncating the Coulomb interaction along the surface normal (z-direction) for a 2D material, using no vacuum padding and a truncation length of z/2. In this case, half of the simulation box is effectively unused, but the algorithm remains simpler. This configuration can be useful for debugging purposes.

	== Related tags and articles ==		== Related tags and articles ==

Ftran at 09:01, 26 November 2025

2025-11-26T09:01:11Z

← Older revision		Revision as of 09:01, 26 November 2025
Line 8:		Line 8:

	This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).		This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).
	{{NB\|mind\|{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.}}		{{NB\|mind\|
			*{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.
			*This tag is only available as of VASP.6.5.0.}}
	{{NB\|warning\|When padding is used, the vaccum is added on the edges of the cell, as such it is very important that the motif is centered in the simulation box. If you encounter problems using Coulomb truncation with padding, try the same calculations without padding (see examples bellow).}}		{{NB\|warning\|When padding is used, the vaccum is added on the edges of the cell, as such it is very important that the motif is centered in the simulation box. If you encounter problems using Coulomb truncation with padding, try the same calculations without padding (see examples bellow).}}
	== Example ==		== Example ==

Ftran at 08:46, 26 November 2025

2025-11-26T08:46:16Z

← Older revision		Revision as of 08:46, 26 November 2025
Line 3:		Line 3:

	'''Description:'''		'''Description:'''
	{{TAG\|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{~~cite\|~~cite\|vijay:prb:2025}}.		{{TAG\|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite\|vijay:prb:2025}}.

	----		----

Ftran at 08:46, 26 November 2025

2025-11-26T08:46:01Z

← Older revision		Revision as of 08:46, 26 November 2025
Line 3:		Line 3:

	'''Description:'''		'''Description:'''
	{{TAG\|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite\|vijay:~~arxiv~~:~~2024~~}}.		{{TAG\|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite\|cite\|vijay:prb:2025}}.

	----		----

Singraber at 08:12, 24 October 2025

2025-10-24T08:12:16Z

← Older revision		Revision as of 08:12, 24 October 2025
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	{{TAGDEF\|KERNEL_TRUNCATION/FACTOR\| real}}		{{TAGDEF\|KERNEL_TRUNCATION/FACTOR\| real}}
	{{DEF\|KERNEL_TRUNCATION/FACTOR\|$\sqrt{3}$\|if {{~~TAGO~~\|KERNEL_TRUNCATION/IDIMENSIONALITY\|0}}\|1\|if {{~~TAGO~~\|KERNEL_TRUNCATION/IDIMENSIONALITY\|2}}}}		{{DEF\|KERNEL_TRUNCATION/FACTOR\|$\sqrt{3}$\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|0}}\|1\|if {{TAG\|KERNEL_TRUNCATION/IDIMENSIONALITY\|2}}}}

	'''Description:'''		'''Description:'''

Miranda.henrique at 09:05, 14 October 2025

2025-10-14T09:05:52Z

← Older revision		Revision as of 09:05, 14 October 2025
Line 9:		Line 9:
	This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).		This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).
	{{NB\|mind\|{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.}}		{{NB\|mind\|{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.}}
			{{NB\|warning\|When padding is used, the vaccum is added on the edges of the cell, as such it is very important that the motif is centered in the simulation box. If you encounter problems using Coulomb truncation with padding, try the same calculations without padding (see examples bellow).}}
	== Example ==		== Example ==

Miranda.henrique: /* Example */

2025-10-14T08:22:24Z

Example

← Older revision		Revision as of 08:22, 14 October 2025
Line 16:		Line 16:
	LTRUNCATE = T		LTRUNCATE = T
	IDIMENSIONALITY = 2		IDIMENSIONALITY = 2
			ISURFACE = 3
			IPAD = 2
			FACTOR = 1
			}
			</pre>
			In this case an additional empty cell is added along the z direciton as padding. The coulomb interaction is truncated beyond a z length. This ensures maximum usage of the simulation box.

			<pre>
			KERNEL_TRUNCATION {
			LTRUNCATE = T
			IDIMENSIONALITY = 2
			ISURFACE = 3
			IPAD = 1
	FACTOR = 0.5		FACTOR = 0.5
	}		}
	</pre>		</pre>

	This corresponds to ~~truncation~~ along the surface normal (~~<code>~~z~~</code>~~-direction), ~~keeping interactions within~~ half of the ~~cell length in <code>z</code>~~.		This setup corresponds to truncating the Coulomb interaction along the surface normal (z-direction) for a 2D material, using no vacuum padding and a truncation length of z/2. In this case, half of the simulation box is effectively unused, but the algorithm remains simpler. This configuration can be useful for debugging purposes.

	== Related tags and articles ==		== Related tags and articles ==

Miranda.henrique at 07:57, 14 October 2025

2025-10-14T07:57:24Z

← Older revision		Revision as of 07:57, 14 October 2025
Line 8:		Line 8:

	This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).		This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).

	For example, when truncating along <code>z</code>, setting {{TAG\|KERNEL_TRUNCATION/FACTOR}} = 0.5 ensures that electrostatic interactions only occur up to half the cell length in the <code>z</code>-direction, effectively centering the truncated region around the middle of the slab or molecule.
	{{NB\|mind\|{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.}}		{{NB\|mind\|{{TAG\|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG\|KERNEL_TRUNCATION/FACTOR}} to take effect.}}

Miranda.henrique: Created page with "{{TAGDEF|KERNEL_TRUNCATION/FACTOR| real}} {{DEF|KERNEL_TRUNCATION/FACTOR|$\sqrt{3}$|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|0}}|1|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|2}}}} '''Description:''' {{TAG|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite|vijay:arxiv:2024}}. ---- This tag defines the cutoff distance of the Coulomb kernel truncati..."

2025-10-14T07:54:34Z

Created page with "{{TAGDEF|KERNEL_TRUNCATION/FACTOR| real}} {{DEF|KERNEL_TRUNCATION/FACTOR|$\sqrt{3}$|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|0}}|1|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|2}}}} '''Description:''' {{TAG|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite|vijay:arxiv:2024}}. ---- This tag defines the cutoff distance of the Coulomb kernel truncati..."

New page

{{TAGDEF|KERNEL_TRUNCATION/FACTOR| real}}
{{DEF|KERNEL_TRUNCATION/FACTOR|$\sqrt{3}$|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|0}}|1|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|2}}}}

'''Description:'''
{{TAG|KERNEL_TRUNCATION/FACTOR}} determines the spatial extent of the truncated Coulomb interaction relative to the full cell dimension along the truncation direction{{cite|vijay:arxiv:2024}}.

----

This tag defines the cutoff distance of the Coulomb kernel truncation boundary. It is expressed as a fraction of the simulation cell length along the truncated axis (e.g., the surface normal for 2D systems).

For example, when truncating along <code>z</code>, setting {{TAG|KERNEL_TRUNCATION/FACTOR}} = 0.5 ensures that electrostatic interactions only occur up to half the cell length in the <code>z</code>-direction, effectively centering the truncated region around the middle of the slab or molecule.
{{NB|mind|{{TAG|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG|KERNEL_TRUNCATION/FACTOR}} to take effect.}}

== Example ==

<pre>
KERNEL_TRUNCATION {
LTRUNCATE = T
IDIMENSIONALITY = 2
FACTOR = 0.5
}
</pre>

This corresponds to truncation along the surface normal (<code>z</code>-direction), keeping interactions within half of the cell length in <code>z</code>.

== Related tags and articles ==
{{TAG|KERNEL_TRUNCATION/LTRUNCATE}},
{{TAG|KERNEL_TRUNCATION/IDIMENSIONALITY}},
{{TAG|KERNEL_TRUNCATION/LCOARSEN}},
{{TAG|KERNEL_TRUNCATION/IPAD}},
{{TAG|KERNEL_TRUNCATION/ISURFACE}}

== References ==

[[Category:INCAR tag]]
[[Category:Electrostatics]]