Evidence class: synthetic-only. This deterministic fixture takes five invented polarization representatives and an invented polarization quantum. It chooses, at every path point, the branch nearest to the preceding point. The exercise makes a continuous reported difference; it does not calculate a Berry phase, a gap, an energy barrier, or a material polarization.
Do not begin a material analysis with this fixture. First save the nonpolar and polar endpoint structures plus every numbered intermediate image; open them together in VESTA or ASE GUI to check atom correspondence and distortion direction; and collect, for every image, the raw Berry-phase representative, polarization quantum, total energy, cell, electronic state, and band gap from one consistent VASP or Quantum ESPRESSO parent series. Use the invented numbers below only after those real objects exist.
Optional toy for branch arithmetic
This page contains no endpoint structures or actual Berry-phase output. Plot the real polarization representative, unwrapped branch, energy, and insulating gap on one path coordinate before making a path decision; calculation routes are indexed under electronic properties.
Optional replay of the invented fixture
python3 examples/practical-guides/polarization_branch_path.py \
--svg public/media/practical-guides/polarization-and-ferroelectricity/unwrap-a-polarization-branch-path/polarization-branch-path.svgWhat this guide verifies
Execution verifies only invented-number branch unwrapping, continuity relative to the declared quantum, and original SVG rendering. A real path additionally needs compatible endpoints, an insulating state at every image, reciprocal-space convergence, and scientific interpretation of the reference structure and switching route.
If the toy script fails, treat that as a local fixture or file-path problem. If a real image becomes metallic, changes cell or electronic state unexpectedly, swaps atom identity, or cannot be joined continuously to its neighbours, stop the polarization claim and repair or redesign the physical path rather than forcing a branch choice.
What this example does not establish
It does not calculate a Berry phase, dielectric response, spontaneous polarization, switching barrier, coercive field, polar ground state, ferroelectricity, finite-temperature transition, or a scientific conclusion for a material.