Function estimate_simulation_runtime 

pub fn estimate_simulation_runtime(network: &Network) -> RuntimeEstimate

Estimate simulation runtime from a fully loaded network.

Advisory only — does not influence time-step selection, convergence behaviour, or any simulation result. For identical network inputs the output is deterministic.

Cost model increases monotonically with: hydraulic step count (duration / hyd_step), network size (nodes + links), mesh density, and quality step count when quality is enabled. Larger/longer simulations will not systematically receive lower estimates than smaller/shorter ones.