K MULTIPLY: Difference between revisions
Created page with "{{DISPLAYTITLE:K_MULTIPLY}} {{TAGDEF|K_MULTIPLY|[integer array]}} {{DEF|K_MULTIPLY|-1 -1 -1|if not set in {{FILE|INCAR}}}} Description: {{TAG|K_MULTIPLY}} sets the per-direction k-point grid multiplier for downsampling from a denser {{FILE|WAVECAR}} ---- {{TAG|K_MULTIPLY}} specifies the ratio between the denser k-point grid stored in the {{FILE|WAVECAR}} (or {{FILE|vaspwave.h5}}) and the coarser grid of the current calculation, for each of the three reciprocal-lattice..." |
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K_MULTIPLY = 12 12 1 | K_MULTIPLY = 12 12 1 | ||
Each value specifies the multiplier for the first, second, and third reciprocal-lattice direction, respectively. This is required when the dense-to-coarse grid ratio is not the same in every direction. | Each value specifies the multiplier for the first, second, and third reciprocal-lattice direction, respectively. This is required when the dense-to-coarse grid ratio is not the same in every direction. | ||
{{NB| warning | All values must be positive integers. Providing any number of values other than 1 or 3 will cause an error.}} | {{NB| warning | All values must be positive integers. Providing any number of values other than 1 or 3 will cause an error.}} | ||
{{NB|mind|Available as of 6.6.1.}} | |||
== Related tags and articles== | == Related tags and articles== | ||
{{TAG|LDOWNSAMPLE}} | {{TAG|LDOWNSAMPLE}} | ||
Revision as of 07:52, 16 April 2026
K_MULTIPLY = [integer array]
| Default: K_MULTIPLY | = -1 -1 -1 | if not set in INCAR |
Description: K_MULTIPLY sets the per-direction k-point grid multiplier for downsampling from a denser WAVECAR
K_MULTIPLY specifies the ratio between the denser k-point grid stored in the WAVECAR (or vaspwave.h5) and the coarser grid of the current calculation, for each of the three reciprocal-lattice directions independently.
When K_MULTIPLY is set, LDOWNSAMPLE is automatically set to LDOWNSAMPLE = .TRUE..
By default, LDOWNSAMPLE triggers an automatic search that tries the same multiplier in all three directions. This works for isotropic grids but fails for anisotropic ones, e.g., when the WAVECAR contains a 24×24×1 grid and the current calculation uses a 2×2×1 grid (requiring multipliers 12, 12, 1). In such cases, K_MULTIPLY must be set explicitly.
| Tip: For isotropic grids the automatic search is fast and K_MULTIPLY is not required. Use K_MULTIPLY when the grid ratio differs between directions. |
| Mind: Available as of VASP 6.5.0 |
Usage
Single value
K_MULTIPLY = 2
The value is replicated to all three directions, equivalent to K_MULTIPLY = 2 2 2.
Three values (anisotropic)
K_MULTIPLY = 12 12 1
Each value specifies the multiplier for the first, second, and third reciprocal-lattice direction, respectively. This is required when the dense-to-coarse grid ratio is not the same in every direction.
| Warning: All values must be positive integers. Providing any number of values other than 1 or 3 will cause an error. |
| Mind: Available as of 6.6.1. |