Qiskit / qiskit-fermions / 33626627795

98%

push

github

feat: add a C API for the edge- and transfer-vertex operators (#303)

Both representations were implemented in `core` and exposed in Python, but had
no C bindings, breaking the core -> pyext -> cext contract the other operator
types follow. The exposed surface matches the existing cext subset rather than
the larger pyext one.

No `core` changes were needed: `canonical_order` and the commutators are
generic over `OperatorTrait` and were already tested against both types.

`normal_ordered` takes `ascending` for the edge operator but not the transfer
one. This asymmetry is deliberate: `E_kj = -E_jk` gives every edge operator two
representations to choose between, whereas `T_jk` and `T_kj` are different
operators, so a transfer-side flag would have nothing to select.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

563 of 567 new or added lines in 5 files covered. (99.29%)

12900 of 13148 relevant lines covered (98.11%)

499282.96 hits per line