VASP optcell/native constrained-cell practical examples

Recreate4figures/2CSV from actual reference numbers without DFT:
  bash run.sh

Full eleven-case own-directory Slurm calculation:
  bash prepare.sh
  bash calculate.sh
  bash status.sh
After all jobs finish:
  bash verify.sh

prepare.sh uses installed VASPKIT1.5.1 task103 to prepare licensed Mo_sv,S,Si
POTCARs in your own work; no POTCAR/binary/full SCF output is distributed.
calculate.sh submits each task once, oneGPUeach, with matching P100/V10016
VASP6.6.1 modules and current excluded partition membership. Do not delete
SUBMISSIONS.json and resubmit completed calculations. Numeric checks and
freshly calculated figures reside in work/analysis and work/figures.
run.sh always replots the supplied reference results, not your new run.

Eleven cases: three orthorhombic six-atom MoS2 vacuum/fixed-cell controls,
two Si8single-axis, two constant-volume/shape-changing ISIF4, two
constant-shape/volume-changing ISIF7, two nonorthogonal shear constraints.
EDIFF1e-6 and ionic force0.02eV/A. These are small procedural examples;
kmesh/Pulay stress and production material-property convergence are not claimed.

IOPTCELL masks the Cartesian deformation-force tensor, not nine independent
POSCAR entries. With a nonorthogonal cell, diagonal-only or shear-only force
masks do not necessarily fix the corresponding lattice-matrix entries.
Native LATTICE_CONSTRAINTS masks tensor rows/columns; the shear pair therefore
has intentionally different allowed freedoms and is not an equivalence test.
All-one IOPTCELL cases are native ISIF4/7 controls, not new independent constraints.
