pub fn build_ptdf(
case: &IndexedNetwork<'_>,
conv: DcConvention,
) -> Result<CsMat<f64>>Expand description
PTDF (m × n): branch flows from nodal injections, f = PTDF · p. Every
reference-bus column is zero. The Laplacian is grounded at the whole
reference set (reference_bus_indices), one row/column per slack. One
reference per island handles disconnected networks; several references within
one island fixes all of those bus angles to zero.