Improvements to path length code

gplugins/path_length_analysis/path_length_analysis_from_gds.py

@@ -8,6 +8,7 @@
 import numpy as np
 import shapely as sh
 import shapely.ops as ops
+from gdsfactory.typings import List, Optional, Tuple
 from klayout.db import DPoint, Polygon
 from scipy.signal import savgol_filter
 from scipy.spatial import distance
@@ -240,6 +241,8 @@ def extract_paths(
     filter_function: Callable = None,
     under_sampling: int = 1,
     evanescent_coupling: bool = False,
+    consider_ports: Optional[List[str]] = None,
+    port_positions: Optional[List[Tuple]] = None,
 ) -> dict:
     """Extracts the centerline of a component or instance from a GDS file.
 
@@ -254,11 +257,41 @@ def extract_paths(
         under_sampling: under sampling factor of the polygon points.
         evanescent_coupling: if True, it assumes that there is evanescent coupling
             between ports not physically connected.
+        consider_ports: if specified, it only considers paths between the specified port names
+            and ignores all other existing ports. Note - this will not work in cases where the
+            specified ports are only coupled evanescently. In this case, it is better to
+            run the function with consider_ports = None and then filter the returned dict.
+        port_positions: if specified, we ignore the existing ports on the component and instead
+            create new ports at the specified positions. Overrides the parameter consider_ports.
+            Note - this will not work in cases where the specified port positions are only coupled
+            evanescently. A workaround for this limitation is to specify one additional port that is
+            physically connected to the ports of interest, for each port of interest.
     """
 
     ev_paths = None
 
-    n_ports = len(component.ports)
+    if port_positions is not None:
+        # Create ports at the specified positions
+        consider_ports = []
+        new_component = component.copy()
+        for i, pos in enumerate(port_positions):
+            pname = f"pl{i}"
+            # The port width and orientation are irrelevant but need to be specified
+            new_component.add_port(
+                name=pname, center=pos, layer=layer, width=0.3, orientation=0
+            )
+            consider_ports.append(pname)
+
+        component = new_component
+
+    if consider_ports is not None:
+        # Only ports in the specified list
+        consider_ports = [component.ports[port_name] for port_name in consider_ports]
+    else:
+        # All ports
+        consider_ports = component.ports
+
+    n_ports = len(consider_ports)
     if n_ports == 0:
         raise ValueError(
             "The specified component does not have ports - path length extraction will not work."
@@ -284,12 +317,12 @@ def extract_paths(
         if n_ports == 2:
             # This is the simplest case - a straight or a bend
             centerline = centerline_single_poly_2_ports(
-                poly, under_sampling, component.ports
+                poly, under_sampling, consider_ports
             )
             if filter_function is not None:
                 centerline = filter_function(centerline)
             p = gf.Path(centerline)
-            paths[f"{component.ports[0].name};{component.ports[1].name}"] = p
+            paths[f"{consider_ports[0].name};{consider_ports[1].name}"] = p
 
         else:
             # Single polygon and more than 2 ports - MMI
@@ -332,7 +365,7 @@ def extract_paths(
             # Need to check how many ports does that specific polygon contain
             ports_poly = list()
 
-            for port in component.ports:
+            for port in consider_ports:
                 if poly.sized(0.005).inside(DPoint(port.center[0], port.center[1])):
                     ports_poly.append(port)
 
@@ -346,6 +379,10 @@ def extract_paths(
                 p = gf.Path(centerline)
                 paths[f"{ports_poly[0].name};{ports_poly[1].name}"] = p
 
+            elif len(ports_poly) == 0:
+                # No ports in the polygon - continue
+                continue
+
             else:
                 # More than 2 ports and multiple polygons
                 # We will assume that means that we are trying to get path
@@ -626,7 +663,12 @@ def _demo_routes():
     # c = gf.import_gds(gdspath)
     # p = extract_path(c, plot=False, window_length=None, polyorder=None)
     path_dict, ev_path_dict = extract_paths(
-        c0, plot=True, under_sampling=1, evanescent_coupling=ev_coupling
+        c0,
+        plot=True,
+        under_sampling=1,
+        evanescent_coupling=ev_coupling,
+        # consider_ports=["o2", "o3"],
+        port_positions=[(-10.0, -1.6), (30.0, -1.6)],
     )
     r_and_l_dict = get_min_radius_and_length_path_dict(path_dict)
     for ports, (min_radius, length) in r_and_l_dict.items():