Function build_ac_pf_preparation 

pub fn build_ac_pf_preparation(
    instance: &AcPfInstance,
    options: &AcPfAssemblyOptions,
) -> Result<AcPfPreparation>

Derive the complete matrix free AC power flow arrays from an instance. The caller’s bus specifications remain authoritative. Network bus types are used only by AcPfInstance::from_network when it creates those specifications; this function does not infer them again.

Errors

A specification layout that leaves an energized component without a reference bus, or a branch pi model that cannot be assembled.