inire/examples/09_unroutable_best_effort.py

from inire.geometry.collision import CollisionEngine
from inire.geometry.primitives import Port
from inire.router.astar import AStarContext, AStarMetrics
from inire.router.cost import CostEvaluator
from inire.router.danger_map import DangerMap
from inire.router.pathfinder import PathFinder
from inire.utils.visualization import plot_routing_results
from shapely.geometry import box

def main() -> None:
    print("Running Example 09: Best-Effort Under Tight Search Budget...")

    # 1. Setup Environment
    bounds = (0, 0, 100, 100)
    engine = CollisionEngine(clearance=2.0)

    # A small obstacle cluster keeps the partial route visually interesting.
    obstacles = [
        box(35, 35, 45, 65),
        box(55, 35, 65, 65),
    ]
    for obs in obstacles:
        engine.add_static_obstacle(obs)

    danger_map = DangerMap(bounds=bounds)
    danger_map.precompute(obstacles)

    evaluator = CostEvaluator(engine, danger_map, bend_penalty=50.0, sbend_penalty=150.0)
    # Keep the search budget intentionally tiny so the router returns a partial path.
    context = AStarContext(evaluator, node_limit=3, bend_radii=[10.0])
    metrics = AStarMetrics()

    pf = PathFinder(context, metrics, warm_start=None)

    # 2. Define Netlist: reaching the target requires additional turns the search budget cannot afford.
    netlist = {
        "budget_limited_net": (Port(10, 50, 0), Port(85, 60, 180)),
    }
    net_widths = {"budget_limited_net": 2.0}

    # 3. Route
    print("Routing with a deliberately tiny node budget (should return a partial path)...")
    results = pf.route_all(netlist, net_widths)

    # 4. Check Results
    res = results["budget_limited_net"]
    if not res.reached_target:
        print(f"Target not reached as expected. Partial path length: {len(res.path)} segments.")
    else:
        print("The route unexpectedly reached the target. Increase difficulty or reduce the node budget further.")

    # 5. Visualize
    fig, ax = plot_routing_results(results, obstacles, bounds, netlist=netlist)
    fig.savefig("examples/09_unroutable_best_effort.png")
    print("Saved plot to examples/09_unroutable_best_effort.png")

if __name__ == "__main__":
    main()