pub fn fermionic_subsystem_phases(
local_dimensions: &[usize],
retained_sites: &[usize],
) -> Result<Vec<f64>>Expand description
Fock-space signs induced by grouping selected fermionic modes into a subsystem. The returned phase is indexed by the original packed state.
Modes inside the environment and subsystem keep the orders supplied by the ordinary subsystem layout; only the swaps needed to group the two factors contribute a sign.