optiwindnet.baselines.hgs

Module Contents

optiwindnet.baselines.hgs.hgs_cvrp(A: networkx.Graph, *, capacity: float, time_limit: float, vehicles: int | None = None, vehicles_exact: bool = False, seed: int | None = None, keep_log: bool = False, repair: bool = True, max_retries: int = 10, balanced: bool = False, log_callback: Callable | None = None) → networkx.Graph[source]

Solves the OCVRP using HGS-CVRP with links from A.

Wraps HybGenSea, which provides bindings to the HGS-CVRP library (Hybrid Genetic Search solver for Capacitated Vehicle Routing Problems). This function uses it to solve an Open-CVRP i.e., vehicles do not return to the depot.

Normalization of input graph is recommended before calling this function.

For single-root problems, the solver runs on the full graph. For multi-root problems, the graph is clustered and each cluster is solved concurrently.

By default, vehicles is an upper bound on the feeder count: HGS-CVRP is free to use fewer, which it normally does, since a shorter solution seldom needs more than the minimum ceil(T / capacity) feeders. Pass vehicles_exact=True to pin the count to vehicles instead. This is only implemented together with balanced=True: the slack nodes that make the loads balanced also make every route come out full, so no route can be left empty and the feeder count is necessarily vehicles.

For multi-root instances, the vehicles (feeders) parameter can only be left undefined (meaning unlimited) or set to the minimum feasible value. Any other value results in a warning and the minimum being used, or, if vehicles_exact=True, in a ValueError.

If repair=True (the default), the solution is iteratively repaired until no crossings remain (or max_retries is reached). This may cause the actual runtime to be up to (max_retries + 1) times the given time_limit.

Parameters:

  • A – graph with allowed edges (if it has 0 edges, use complete graph)

  • capacity – maximum vehicle capacity

  • time_limit – [s] solver run time limit

  • vehicles – maximum number of vehicles (if None, let HGS-CVRP decide; clamped to the minimum for multi-root problems); the exact number of vehicles if vehicles_exact=True

  • vehicles_exact – whether vehicles is the exact feeder count instead of an upper bound (requires balanced=True, a single root, and ceil(T / capacity) <= vehicles <= T)

  • seed – random seed for reproducibility

  • keep_log – attach solver log to the solution graph

  • repair – iteratively fix crossings (default True)

  • max_retries – maximum repair iterations

  • balanced – balance loads across feeders (per root, if multiple roots)

  • log_callback – callback to receive each log line produced by HGS-CVRP (only for single-root instances)

Returns:

Solution topology S

optiwindnet.baselines.hgs.iterative_hgs_cvrp(A: networkx.Graph, *, capacity: float, time_limit: float, vehicles: int | None = None, seed: int | None = None, max_retries: int = 10, keep_log: bool = False, complete: bool = False) → networkx.Graph[source]

DEPRECATED: Backward-compatible alias of hgs_cvrp(), use it instead.

optiwindnet.baselines.hgs.hgs_multiroot(A: networkx.Graph, *, capacity: int, time_limit: float, balanced: bool = False, seed: int | None = None, keep_log: bool = False) → networkx.Graph[source]

DEPRECATED: Backward-compatible alias of hgs_cvrp(), use it instead.