incar-smearing-precision

name	incar-smearing-precision
description	Choose and validate VASP smearing, precision, and static/relax accuracy tags such as ISMEAR, SIGMA, EDIFF, PREC, LREAL, LASPH, ADDGRID, and related output precision settings. Use when preparing INCAR for metals, semiconductors, insulators, surfaces, DOS/band calculations, or energy comparisons.

INCAR Smearing and Precision

Use this skill as an INCAR modifier whenever occupation and precision choices affect accuracy or convergence.

INCAR Contract

Adds or Sets

• ISMEAR and SIGMA based on material class and workflow stage.
• EDIFF, PREC, LREAL, LASPH, and related accuracy tags when the workflow template is incomplete.
• Static/DOS/band choices that differ from relaxation choices, documented in notes.

Defaults

• Unknown semiconductor/insulator: conservative Gaussian smearing, typically ISMEAR = 0, small SIGMA.
• Metal relaxation or metallic surface: metallic smearing may be appropriate, but keep the choice consistent across energy differences.
• DOS and band-structure post-SCF steps require careful occupation settings and should not silently inherit a rough relaxation INCAR.

Forbids

• Do not use a large metallic SIGMA for final bandgap extraction unless the workflow explicitly uses it as a controlled approximation.
• Do not compare energies across directories with different smearing settings unless that difference is the study variable.
• Do not lower precision tags just to speed up a production calculation; route performance-only requests through incar-performance.

Handoff

After applying this modifier, call incar-validator before run-vasp if the calculation will be submitted.