pd-code-reverse-component

Reverse the orientation encoding of one selected PD-code component.

Installation

pip install pd-code-reverse-component

Usage example

from pd_code_reverse_component import reverse_component

pd = [[2, 3, 1, 4], [4, 1, 3, 2]]
reversed_pd = reverse_component(pd, 1)
print(reversed_pd)

Algorithm

The selected label identifies its component cycle through predecessor/successor maps. The cycle is placed in canonical order and mapped to its reverse order. Every occurrence of a component label is replaced through that bijection; labels belonging to other components remain unchanged. The operation returns a deep copy and leaves the input untouched.

Input conventions

A PD code is represented as a list of four-entry crossings. Arc labels normally occur exactly twice. Public functions validate inputs and return new values rather than mutating caller-owned data unless their API explicitly says otherwise.

External software

No external software is required.

Development

Run examples and package checks before release. Python packages require Python 3.10 or newer. Build PyPI artifacts with:

poetry check
poetry build

License

MIT. See LICENSE.