Computational Input Generation

Quick Decision Guide

Task	Tool
VASP input (INCAR/POSCAR/KPOINTS)	catgo_vasp_generate
Quantum ESPRESSO pw.x input	catgo_qe_generate
LAMMPS input + data file	catgo_lammps_generate
Multi-stage LAMMPS simulation	catgo_lammps_sequential
ML potential relaxation	catgo_optimize
Single-point energy/forces	catgo_energy
List available calculators	catgo_calculators

VASP Input

catgo_vasp_generate

• Calculation types: opt, scf, freq, bader, dos, ddec, elf
• Key params: encut (default 450 eV), gga ("PE"=PBE), ispin (2=spin-polarized), ivdw (12=D3-BJ), kspacing, fixed_indices/fixed_z_below

Common patterns:

• Bulk optimization: calculation_type="opt", isif=3 (relax cell+ions)
• Slab optimization: calculation_type="opt", isif=2, fixed_z_below=Z
• DOS: calculation_type="dos", dense k-mesh

Call catgo_vasp_calc_types to list all available types with defaults.

Quantum ESPRESSO Input

catgo_qe_generate

• Calculation types: scf, relax, vc-relax, nscf, bands
• Key params: ecutwfc (default 60 Ry), ecutrho (default 480 Ry), kspacing, occupations, smearing ("mv"=Marzari-Vanderbilt), nspin

Call catgo_qe_templates for recommended settings per calculation type.

LAMMPS Input

catgo_lammps_generate

• Simulation types: minimize, nve, nvt, npt
• Key params: pair_style, pair_coeff, potential_file, temperature, pressure

catgo_lammps_sequential — Multi-stage MD protocol:

{"stages": [
  {"name": "minimize", "simulation_type": "minimize"},
  {"name": "heat", "simulation_type": "nvt", "temperature": 300, "run_steps": 10000},
  {"name": "equilibrate", "simulation_type": "npt", "temperature": 300, "run_steps": 50000},
  {"name": "production", "simulation_type": "nvt", "temperature": 300, "run_steps": 100000}
]}

Call catgo_lammps_pair_styles for available force fields. Call catgo_lammps_validate before generating to check configuration.

ML Potential Optimization

catgo_optimize

Quick relaxation using ML interatomic potentials:

• mace: Best accuracy for most systems
• chgnet: Good for oxides
• m3gnet: General purpose
• emt: Fast, metals only (testing)

Params: fmax (default 0.05 eV/A), max_steps (200), relax_cell (True to relax lattice)

catgo_energy — Single-point energy + forces without optimization.

Workflow Recipes

ML Pre-Optimization then DFT

1. catgo_optimize(calculator="mace", fmax=0.05) → 2. catgo_vasp_generate(calculation_type="opt")

VASP Slab Calculation

1. Build slab → 2. catgo_vasp_generate(calculation_type="opt", isif=2, fixed_z_below=Z, encut=520)