Function build_dc_opf_preparation 

pub fn build_dc_opf_preparation(
    instance: &DcOpfInstance,
    options: &DcOpfAssemblyOptions,
) -> Result<DcOpfPreparation>

Derive the complete matrix free DC OPF arrays from the instance: demand, shunt, and phase shift withdrawals, generator costs and bounds with their source row mapping, branch susceptances as positive solver edge weights, thermal limits, angle bounds, and the reference bus set. This is the one numerical assembly the matrix builders, the bundle writer, and external solvers read, published so each consumer formulates over the same arrays instead of re-deriving them from the network. DcOpfPreparation documents each field’s unit and sign.

Errors

As calc_dc_opf_matrices.