improve exmples

DOCS.md

@@ -51,3 +51,28 @@ The `CostEvaluator` defines the "goodness" of a path.
 -   **Coordinates**: Micrometers (µm).
 -   **Grid Snapping**: The router internally operates on a **1nm** grid for final ports and a **1µm** lattice for expansion moves.
 -   **Search Space**: Assumptions are optimized for design areas up to **20mm x 20mm**.
+
+---
+
+## 5. Best Practices & Tuning Advice
+
+### Speed vs. Optimality
+The `greedy_h_weight` is your primary lever for search performance.
+-   **`1.0`**: Dijkstra-like behavior. Guarantees the shortest path but is very slow.
+-   **`1.1` to `1.2`**: Recommended range. Balances wire length with fast convergence.
+-   **`> 1.5`**: Extremely fast "greedy" search. May produce zig-zags or suboptimal detours.
+
+### Avoiding "Zig-Zags"
+If the router produces many small bends instead of a long straight line:
+1.  Increase `bend_penalty` (e.g., set to `100.0` or higher).
+2.  Ensure `straight_lengths` includes larger values like `25.0` or `100.0`.
+3.  Decrease `greedy_h_weight` closer to `1.0`.
+
+### Handling Congestion
+In multi-net designs, if nets are overlapping:
+1.  Increase `congestion_penalty` in `CostEvaluator`.
+2.  Increase `max_iterations` in `PathFinder`.
+3.  If a solution is still not found, check if the `clearance` is physically possible given the design's narrowest bottlenecks.
+
+### S-Bend Usage
+Parametric S-bends are triggered by the `sbend_offsets` list. If you need a specific lateral shift (e.g., 5.86µm for a 45° switchover), add it to `sbend_offsets`. The router will only use an S-bend if it can reach a state that is exactly on the lattice or the target.

README.md

@@ -62,6 +62,8 @@ Check the `examples/` directory for ready-to-run scripts demonstrating core feat
 *   **`examples/01_simple_route.py`**: Basic single-net routing with visualization.
 *   **`examples/02_congestion_resolution.py`**: Multi-net routing resolving bottlenecks using Negotiated Congestion.
 *   **`examples/03_locked_paths.py`**: Incremental workflow using `lock_net()` to route around previously fixed paths.
+*   **`examples/04_sbends_and_radii.py`**: Complex paths using parametric S-bends and multiple bend radii.
+*   **`examples/05_orientation_stress.py`**: Stress test for various port orientation combinations (U-turns, opposite directions).
 
 Run an example:
 ```bash

examples/02_congestion_resolution.py

@@ -1,4 +1,3 @@
-
 from inire.geometry.collision import CollisionEngine
 from inire.geometry.primitives import Port
 from inire.router.astar import AStarRouter
@@ -9,7 +8,7 @@ from inire.utils.visualization import plot_routing_results
 
 
 def main() -> None:
-    print("Running Example 02: Congestion Resolution (Crossing)...")
+    print("Running Example 02: Congestion Resolution (Triple Crossing)...")
 
     # 1. Setup Environment (Open space)
     bounds = (0, 0, 100, 100)
@@ -22,23 +21,24 @@ def main() -> None:
     pf = PathFinder(router, evaluator)
 
     # 2. Define Netlist
-    # Two nets that MUST cross.
-    # Since crossings are illegal in single-layer routing, one net must detour around the other.
+    # Three nets that all converge on the same central area.
+    # Negotiated Congestion must find non-overlapping paths for all of them.
     netlist = {
         "horizontal": (Port(10, 50, 0), Port(90, 50, 0)),
-        "vertical": (Port(50, 10, 90), Port(50, 90, 90)),
+        "vertical_up": (Port(45, 10, 90), Port(45, 90, 90)),
+        "vertical_down": (Port(55, 90, 270), Port(55, 10, 270)),
     }
-    net_widths = {"horizontal": 2.0, "vertical": 2.0}
+    net_widths = {nid: 2.0 for nid in netlist}
 
     # 3. Route with Negotiated Congestion
     # We increase the base penalty to encourage faster divergence
-    pf.base_congestion_penalty = 500.0
+    pf.base_congestion_penalty = 1000.0
     results = pf.route_all(netlist, net_widths)
 
     # 4. Check Results
     all_valid = all(r.is_valid for r in results.values())
     if all_valid:
-        print("Success! Congestion resolved (one net detoured).")
+        print("Success! Congestion resolved for all nets.")
     else:
         print("Some nets failed or have collisions.")
         for nid, res in results.items():

examples/03_locked_paths.py

@@ -1,4 +1,3 @@
-
 from inire.geometry.collision import CollisionEngine
 from inire.geometry.primitives import Port
 from inire.router.astar import AStarRouter
@@ -9,68 +8,64 @@ from inire.utils.visualization import plot_routing_results
 
 
 def main() -> None:
-    print("Running Example 03: Locked Paths (Incremental Routing)...")
+    print("Running Example 03: Locked Paths (Incremental Routing - Bus Scenario)...")
 
     # 1. Setup Environment
-    bounds = (0, 0, 100, 100)
+    bounds = (0, 0, 120, 120)
     engine = CollisionEngine(clearance=2.0)
     danger_map = DangerMap(bounds=bounds)
-    danger_map.precompute([]) # No initial obstacles
+    danger_map.precompute([]) # Start with empty space
 
-    evaluator = CostEvaluator(engine, danger_map)
-    router = AStarRouter(evaluator)
+    evaluator = CostEvaluator(engine, danger_map, greedy_h_weight=1.2)
+    router = AStarRouter(evaluator, node_limit=200000)
     pf = PathFinder(router, evaluator)
 
-    # 2. Phase 1: Route a "Critical" Net
-    # This net gets priority and takes the best path.
-    netlist_phase1 = {
-        "critical_net": (Port(10, 50, 0), Port(90, 50, 0)),
+    # 2. Phase 1: Route a "Bus" of 3 parallel nets
+    # We give them a small jog to make the locked geometry more interesting
+    netlist_p1 = {
+        "bus_0": (Port(10, 40, 0), Port(110, 45, 0)),
+        "bus_1": (Port(10, 50, 0), Port(110, 55, 0)),
+        "bus_2": (Port(10, 60, 0), Port(110, 65, 0)),
     }
-    print("Phase 1: Routing critical_net...")
-    results1 = pf.route_all(netlist_phase1, {"critical_net": 3.0}) # Wider trace
+    print("Phase 1: Routing bus (3 nets)...")
+    results_p1 = pf.route_all(netlist_p1, {nid: 2.0 for nid in netlist_p1})
 
-    if not results1["critical_net"].is_valid:
-        print("Error: Phase 1 failed.")
-        return
+    # Lock all Phase 1 nets
+    path_polys = []
+    for nid, res in results_p1.items():
+        if res.is_valid:
+            print(f"  Locking {nid}...")
+            engine.lock_net(nid)
+            path_polys.extend([p for comp in res.path for p in comp.geometry])
+        else:
+            print(f"  Warning: {nid} failed to route correctly.")
 
-    # 3. Lock the Critical Net
-    # This converts the dynamic path into a static obstacle in the collision engine.
-    print("Locking critical_net...")
-    engine.lock_net("critical_net")
-
-    # Update danger map to reflect the new obstacle (optional but recommended for heuristics)
-    # Extract polygons from result
-    path_polys = [p for comp in results1["critical_net"].path for p in comp.geometry]
+    # Update danger map with the newly locked geometry
+    print("Updating DangerMap with locked paths...")
     danger_map.precompute(path_polys)
 
-    # 4. Phase 2: Route a Secondary Net
-    # This net must route *around* the locked critical_net.
-    # Start and end points force a crossing path if it were straight.
-    netlist_phase2 = {
-        "secondary_net": (Port(50, 10, 90), Port(50, 90, 90)),
+    # 3. Phase 2: Route secondary nets that must navigate around the locked bus
+    # These nets cross the bus vertically.
+    netlist_p2 = {
+        "cross_left": (Port(30, 10, 90), Port(30, 110, 90)),
+        "cross_right": (Port(80, 110, 270), Port(80, 10, 270)), # Top to bottom
     }
     
-    print("Phase 2: Routing secondary_net around locked path...")
-    results2 = pf.route_all(netlist_phase2, {"secondary_net": 2.0})
+    print("Phase 2: Routing crossing nets around locked bus...")
+    # We use a slightly different width for variety
+    results_p2 = pf.route_all(netlist_p2, {nid: 1.5 for nid in netlist_p2})
 
-    if results2["secondary_net"].is_valid:
-        print("Success! Secondary net routed around locked path.")
-    else:
-        print("Failed to route secondary net.")
+    # 4. Check Results
+    for nid, res in results_p2.items():
+        status = "Success" if res.is_valid else "Failed"
+        print(f"  {nid:12}: {status}, collisions={res.collisions}")
 
     # 5. Visualize
-    # Combine results and netlists for plotting
-    all_results = {**results1, **results2}
-    all_netlists = {**netlist_phase1, **netlist_phase2}
-
-    # Note: 'critical_net' is now in engine.static_obstacles internally, 
-    # but for visualization we plot it from the result object to see it clearly.
-    # We pass an empty list for 'static_obstacles' to plot_routing_results 
-    # because we want to see the path colored, not grayed out as an obstacle.
+    all_results = {**results_p1, **results_p2}
+    all_netlists = {**netlist_p1, **netlist_p2}
 
     fig, ax = plot_routing_results(all_results, [], bounds, netlist=all_netlists)
     fig.savefig("examples/locked.png")
-
     print("Saved plot to examples/locked.png")
 
 

examples/04_sbends_and_radii.py

@@ -3,7 +3,6 @@ from shapely.geometry import Polygon
 from inire.geometry.collision import CollisionEngine
 from inire.geometry.primitives import Port
 from inire.router.astar import AStarRouter
-from inire.router.config import CostConfig, RouterConfig
 from inire.router.cost import CostEvaluator
 from inire.router.danger_map import DangerMap
 from inire.router.pathfinder import PathFinder

examples/05_orientation_stress.py

@@ -0,0 +1,56 @@
+from inire.geometry.collision import CollisionEngine
+from inire.geometry.primitives import Port
+from inire.router.astar import AStarRouter
+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
+
+
+def main() -> None:
+    print("Running Example 05: Orientation Stress Test...")
+
+    # 1. Setup Environment
+    # Give some breathing room (-20 to 120) for U-turns and flips (R=10)
+    bounds = (-20, -20, 120, 120)
+    engine = CollisionEngine(clearance=2.0)
+    danger_map = DangerMap(bounds=bounds)
+    danger_map.precompute([])
+    
+    evaluator = CostEvaluator(engine, danger_map, greedy_h_weight=1.1)
+    router = AStarRouter(evaluator, node_limit=100000)
+    pf = PathFinder(router, evaluator)
+    
+    # 2. Define Netlist with various orientation challenges
+    netlist = {
+        # Opposite directions: requires two 90-degree bends to flip orientation
+        "opposite": (Port(10, 80, 0), Port(90, 80, 180)),
+        
+        # 90-degree turn: standard L-shape
+        "turn_90": (Port(10, 60, 0), Port(40, 90, 90)),
+        
+        # Output behind input: requires a full U-turn
+        "behind": (Port(80, 40, 0), Port(20, 40, 0)),
+        
+        # Sharp return: output is behind and oriented towards the input
+        "return_loop": (Port(80, 20, 0), Port(40, 10, 180)),
+    }
+    net_widths = {nid: 2.0 for nid in netlist}
+
+    # 3. Route
+    results = pf.route_all(netlist, net_widths)
+
+    # 4. Check Results
+    for nid, res in results.items():
+        status = "Success" if res.is_valid else "Failed"
+        total_len = sum(comp.length for comp in res.path) if res.path else 0
+        print(f"  {nid:12}: {status}, total_length={total_len:.1f}")
+
+    # 5. Visualize
+    fig, ax = plot_routing_results(results, [], bounds, netlist=netlist)
+    fig.savefig("examples/orientation_stress.png")
+    print("Saved plot to examples/orientation_stress.png")
+
+
+if __name__ == "__main__":
+    main()

inire/router/danger_map.py

@@ -70,6 +70,10 @@ class DangerMap:
         safe_distances = np.maximum(distances, 0.1)
         self.grid = np.where(distances < self.safety_threshold, self.k / (safe_distances**2), 0.0).astype(np.float32)
 
+    def is_within_bounds(self, x: float, y: float) -> bool:
+        """Check if a coordinate is within the design bounds."""
+        return self.minx <= x <= self.maxx and self.miny <= y <= self.maxy
+
     def get_cost(self, x: float, y: float) -> float:
         """Get the proximity cost at a specific coordinate."""
         ix = int((x - self.minx) / self.resolution)
@@ -77,4 +81,4 @@ class DangerMap:
 
         if 0 <= ix < self.width_cells and 0 <= iy < self.height_cells:
             return float(self.grid[ix, iy])
-        return 1e6  # Outside bounds is expensive
+        return 1e15  # Outside bounds is impossible

inire/tests/test_components.py

@@ -1,7 +1,9 @@
+import numpy as np
 import pytest
+from shapely.geometry import Point
 
 from inire.geometry.components import Bend90, SBend, Straight
-from inire.geometry.primitives import Port
+from inire.geometry.primitives import Port, rotate_port, translate_port
 
 
 def test_straight_generation() -> None:
@@ -90,3 +92,67 @@ def test_sbend_collision_models() -> None:
     
     res_arc = SBend.generate(start, offset, radius, width, collision_type="arc")
     assert res_bbox.geometry[0].area > res_arc.geometry[0].area
+
+
+def test_sbend_continuity() -> None:
+    # Verify SBend endpoints and continuity math
+    start = Port(10, 20, 90)  # Starting facing up
+    offset = 4.0
+    radius = 20.0
+    width = 1.0
+    
+    res = SBend.generate(start, offset, radius, width)
+    
+    # Target orientation should be same as start
+    assert abs(res.end_port.orientation - 90.0) < 1e-6
+    
+    # For a port at 90 deg, +offset is a shift in -x direction
+    assert abs(res.end_port.x - (10.0 - offset)) < 1e-6
+    
+    # Geometry should be connected (unary_union results in 1 polygon)
+    assert len(res.geometry) == 1
+    assert res.geometry[0].is_valid
+
+
+def test_arc_sagitta_precision() -> None:
+    # Verify that requested sagitta actually controls segment count
+    start = Port(0, 0, 0)
+    radius = 100.0  # Large radius to make sagitta significant
+    width = 2.0
+    
+    # Coarse: 1um sagitta
+    res_coarse = Bend90.generate(start, radius, width, sagitta=1.0)
+    # Fine: 0.01um (10nm) sagitta
+    res_fine = Bend90.generate(start, radius, width, sagitta=0.01)
+    
+    # Number of segments should be significantly higher for fine
+    # Exterior points = (segments + 1) * 2
+    pts_coarse = len(res_coarse.geometry[0].exterior.coords)
+    pts_fine = len(res_fine.geometry[0].exterior.coords)
+    
+    assert pts_fine > pts_coarse * 2
+
+
+def test_component_transform_invariance() -> None:
+    # Verify that generating at (0,0) then transforming
+    # is same as generating at the transformed port.
+    start0 = Port(0, 0, 0)
+    radius = 10.0
+    width = 2.0
+    
+    res0 = Bend90.generate(start0, radius, width, direction="CCW")
+    
+    # Transform: Translate (10, 10) then Rotate 90
+    dx, dy = 10.0, 5.0
+    angle = 90.0
+    
+    # 1. Transform the generated geometry
+    p_end_transformed = rotate_port(translate_port(res0.end_port, dx, dy), angle)
+    
+    # 2. Generate at transformed start
+    start_transformed = rotate_port(translate_port(start0, dx, dy), angle)
+    res_transformed = Bend90.generate(start_transformed, radius, width, direction="CCW")
+    
+    assert abs(res_transformed.end_port.x - p_end_transformed.x) < 1e-6
+    assert abs(res_transformed.end_port.y - p_end_transformed.y) < 1e-6
+    assert abs(res_transformed.end_port.orientation - p_end_transformed.orientation) < 1e-6