pub fn line3ph_blocks(ln: &Line3Ph) -> [[[Complex<f64>; 3]; 3]; 4]Expand description
The four 3×3 phase-domain π-model blocks of a three-phase line,
[Yff, Yft, Ytf, Ytt] — the same order and meaning as
branch_calc_param’s four scalars.
Extracted so that build_ybus_3ph and the state estimator’s own branch
functionals read one description rather than two. A Y-bus and a measurement
model that disagree about a branch produce an estimate that converges
confidently to the wrong answer, which is the failure mode
tests/measurement_residual_test.rs exists to catch on the symmetric side.