Fix fracture intersection finder for boundary points.

When the new polygon segment intersection algorithm was used, points on
the boundary were found by the method aimed at internal points. Missing
information the segment is on the boundary, the further meshing
algorithm failed.

src/porepy/fracs/fractures.py

@@ -368,8 +368,14 @@ def intersects(self, other, tol, check_point_contact=True):
         # segment of the other.
 
         # Compute intersections, with both polygons as first argument
-        isect_self_other = cg.polygon_segment_intersect(self.p, other.p, tol=tol)
-        isect_other_self = cg.polygon_segment_intersect(other.p, self.p, tol=tol)
+        # Do not include boundary points of the polygons here, these will be
+        # processed later
+        isect_self_other = cg.polygon_segment_intersect(self.p, other.p,
+                                                        tol=tol,
+                                                        include_bound_pt=False)
+        isect_other_self = cg.polygon_segment_intersect(other.p, self.p,
+                                                        tol=tol,
+                                                        include_bound_pt=False)
 
         # Process data
         if isect_self_other is not None:
@@ -397,8 +403,8 @@ def intersects(self, other, tol, check_point_contact=True):
         # There at at the most two intersection points between the fractures
         # (assuming convexity). If two interior points are found, we can simply
         # cut it short here.
-        if int_points.shape[1] == 2:
-            return int_points, on_boundary_self, on_boundary_other
+#        if int_points.shape[1] == 2:
+#            return int_points, on_boundary_self, on_boundary_other
 
         ####
         # Next, check for intersections between the polygon boundaries
@@ -1861,7 +1867,7 @@ def dist_p(a, b):
                 else:
                     isect_f.append(i.first.index)
 
-                # Assuming the fracture is convex, the closest point for 
+                # Assuming the fracture is convex, the closest point for
                 dist, cp = cg.dist_points_segments(i.coord, f.p,
                                                    np.roll(f.p, 1, axis=1))
                 # Insert a (candidate) point only at the segment closest to the