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Calculation Modes

We include calculation modes "rlx-coarse", "rlx", "static", "bulkmod", and "elastic". The desired modes to calculate are specified when initializing a [VaspManager][vasp_manager.VaspManager] object.

  • rlx-coarse: lower precision energy-based relaxation
  • rlx: tighter relaxation (often force-based)
  • static: high accuracy static SCF calculation
  • bulkmod: bulk modulus calculation using an Equation of State (EOS) fit to an energy-volume curve. Each strain point is submitted as an independent static calculation, allowing individual strains to be monitored and rerun separately.
  • elastic: Determination of elastic constants using the strain/deformation method built into VASP

I generally recommend starting from rlx-coarse, although the functionality is there to start a rlx calculation from the initially provided POSCAR.

Most users' workflows follow rlx-coarse → rlx → static. The modes static, bulkmod, and elastic can all be run independently of each other. For example, workflows might look like rlx-coarse → rlx → static → bulkmod, or rlx → elastic, or simply static or bulkmod. The elastic mode requires at least rlx preceding it in order to guarantee converged lattice parameters and atomic positions.

Example workflows are shown below:

graph LR
rlx-coarse --> rlx --> static
graph LR
rlx-coarse --> rlx --> static & bulkmod & elastic
graph LR
rlx --> elastic