Avoid blockages when connecting Hanan points

compiler/router/navigation_graph.py

@@ -78,13 +78,19 @@ class navigation_graph:
                 min_neighbor = None
                 for j in range(i + 1, len(self.nodes)):
                     neighbor = self.nodes[j]
+                    # Skip if not on the same layer
                     if node.center.z != neighbor.center.z:
                         continue
+                    # Calculate the distance vector and distance value
                     distance_vector = neighbor.center - node.center
                     distance = node.center.distance(neighbor.center)
+                    # Skip if not connected rectilinearly
                     if (distance_vector.x or (distance_vector.y * d.y <= 0)) and \
                        (distance_vector.y or (distance_vector.x * d.x <= 0)):
                         continue
+                    # Skip if this connection is blocked by a blockage
+                    if is_probe_blocked(node.center, neighbor.center, self.graph_blockages):
+                        continue
                     if distance < min_dist:
                         min_dist = distance
                         min_neighbor = neighbor
@@ -156,7 +162,7 @@ class navigation_graph:
 
             # Update neighbor scores
             for node in current.neighbors:
-                tentative_score = self.get_edge_cost(current, node) + g_scores[current.id]
+                tentative_score = current.get_edge_cost(node) + g_scores[current.id]
                 if node.id not in g_scores or tentative_score < g_scores[node.id]:
                     came_from[node.id] = current
                     g_scores[node.id] = tentative_score
@@ -165,16 +171,3 @@ class navigation_graph:
 
         # Return None if not connected
         return None
-
-
-    def get_edge_cost(self, source, target):
-        """  """
-
-        if target in source.neighbors:
-            is_vertical = source.center.x == target.center.x
-            layer_dist = source.center.distance(target.center)
-            if is_vertical != bool(source.center.z):
-                layer_dist *= 2
-            via_dist = abs(source.center.z - target.center.z) * 2
-            return layer_dist + via_dist
-        return float("inf")

compiler/router/navigation_node.py

@@ -40,9 +40,14 @@ class navigation_node:
             node.neighbors.remove(self)
 
 
-    def get_edge_cost(self, node):
-        """ Return the cost of going to node. """
+    def get_edge_cost(self, other):
+        """ Get the cost of going from this node to the other node. """
 
-        if node in self.neighbors:
-            return self.center.distance(node.center) + abs(self.center.z - node.center.z)
+        if other in self.neighbors:
+            is_vertical = self.center.x == other.center.x
+            layer_dist = self.center.distance(other.center)
+            if is_vertical != bool(self.center.z):
+                layer_dist *= 2
+            via_dist = abs(self.center.z - other.center.z) * 2
+            return layer_dist + via_dist
         return float("inf")

compiler/router/navigation_router.py

@@ -35,7 +35,8 @@ class navigation_router(router_tech):
 
     def route(self, vdd_name="vdd", gnd_name="gnd"):
         """ Route the given pins in the given order. """
-        debug.info(1, "Running router for {}...".format(pins))
+        #debug.info(1, "Running router for {}...".format(pins))
+        self.write_debug_gds(gds_name="before.gds")
 
         # Prepare gdsMill to find pins and blockages
         self.design.gds_write(self.gds_filename)
@@ -63,7 +64,7 @@ class navigation_router(router_tech):
         # Create the path shapes on layout
         self.add_path(path)
 
-        self.write_debug_gds(source=vdd_0, target=vdd_1)
+        self.write_debug_gds(gds_name="after.gds", source=vdd_0, target=vdd_1)
 
 
     def find_pins(self, pin_name):
@@ -142,13 +143,14 @@ class navigation_router(router_tech):
         """  """
 
         # Display the inflated blockage
-        for blockage in self.nav.graph_blockages:
-            self.add_object_info(blockage, "blockage")
-        for node in self.nav.nodes:
-            offset = (node.center.x, node.center.y)
-            self.design.add_label(text="O",
-                                  layer="text",
-                                  offset=offset)
+        if "nav" in self.__dict__:
+            for blockage in self.nav.graph_blockages:
+                self.add_object_info(blockage, "blockage")
+            for node in self.nav.nodes:
+                offset = (node.center.x, node.center.y)
+                self.design.add_label(text="O",
+                                      layer="text",
+                                      offset=offset)
         if source:
             self.add_object_info(source, "source")
         if target:

compiler/router/navigation_utils.py

@@ -7,6 +7,29 @@
 Utility functions for navigation router.
 """
 
+def is_probe_blocked(p1, p2, blockages):
+    """
+    Return if a probe sent from p1 to p2 encounters a blockage.
+    The probe must be sent vertically or horizontally.
+    This method assumes that blockages are rectangular.
+    """
+
+    # Check if any blockage blocks this probe
+    for blockage in blockages:
+        ll, ur = blockage.rect
+        right_x = ur[0]
+        upper_y = ur[1]
+        left_x = ll[0]
+        lower_y = ll[1]
+        # Check if blocked vertically
+        if is_between(left_x, right_x, p1.x) and (is_between(p1.y, p2.y, upper_y) or is_between(p1.y, p2.y, lower_y)):
+            return True
+        # Check if blocked horizontally
+        if is_between(upper_y, lower_y, p1.y) and (is_between(p1.x, p2.x, left_x) or is_between(p1.x, p2.x, right_x)):
+            return True
+    return False
+
+
 def is_in_region(point, region):
     """"""