KERNEL TRUNCATION/IPAD: Difference between revisions

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(Created page with "{{TAGDEF|KERNEL_TRUNCATION/IPAD| integer}} {{DEF|KERNEL_TRUNCATION/IPAD|3|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|0}}|2|if {{TAGO|KERNEL_TRUNCATION/IDIMENSIONALITY|2}}}} '''Description:''' {{TAG|KERNEL_TRUNCATION/IPAD}} controls the padding strategy used for the Coulomb kernel truncation in reciprocal space. Padding defines how much additional empty space is introduced around the charge density before applying truncation.{{cite|vijay:arxiv:2024}} This affects both...")
 
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{{NB|mind|{{TAG|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG|KERNEL_TRUNCATION/IPAD}} to have any effect.}}
{{NB|mind|{{TAG|KERNEL_TRUNCATION/LTRUNCATE}} must be set to <code>.TRUE.</code> for {{TAG|KERNEL_TRUNCATION/IPAD}} to have any effect.}}


== Default settings ==
== Example ==


The value of {{TAG|KERNEL_TRUNCATION/IPAD}} depends on the system dimensionality:
{| class="wikitable" style="text-align:center;"
! System type
! Typical {{TAG|KERNEL_TRUNCATION/IDIMENSIONALITY}}
! Default {{TAG|KERNEL_TRUNCATION/IPAD}}
|-
| Molecules (0D)
| 0
| 3
|-
| Layer materials (2D)
| 2
| 2
|}
Example:
<pre>
<pre>
KERNEL_TRUNCATION {
KERNEL_TRUNCATION {

Revision as of 07:48, 14 October 2025

KERNEL_TRUNCATION/IPAD = integer 

Default: KERNEL_TRUNCATION/IPAD = 3 if KERNEL_TRUNCATION/IDIMENSIONALITY = 0
= 2 if KERNEL_TRUNCATION/IDIMENSIONALITY = 2

Description: KERNEL_TRUNCATION/IPAD controls the padding strategy used for the Coulomb kernel truncation in reciprocal space. Padding defines how much additional empty space is introduced around the charge density before applying truncation.[1] This affects both the accuracy of the truncated Coulomb potential and the computational cost.


Setting KERNEL_TRUNCATION/IPAD allows fine control over how much zero-padding is applied along each reciprocal-space direction. Padding ensures that the truncated Coulomb kernel does not artificially interact with its periodic replicas in non-periodic directions.

Typically, increasing KERNEL_TRUNCATION/IPAD improves accuracy at the expense of computational cost.

Mind: KERNEL_TRUNCATION/LTRUNCATE must be set to .TRUE. for KERNEL_TRUNCATION/IPAD to have any effect.

Example

KERNEL_TRUNCATION {
     LTRUNCATE      = T
     IDIMENSIONALITY = 2
     IPAD            = 1
}

This corresponds to truncation along the surface normal (z-direction) for a 2D material with one layer of padding.

Related tags and articles

KERNEL_TRUNCATION/LTRUNCATE, KERNEL_TRUNCATION/IDIMENSIONALITY, KERNEL_TRUNCATION/LCOARSEN, KERNEL_TRUNCATION/ISURFACE

References