In column_track() base tolerance on local rather than global grid size

Author: acroucher

mulgrids.py

@@ -2005,8 +2005,6 @@ def column_track(self, line):
 
         tol = 1e-3
         def track_dist(p): return norm(p - line[0])
-        dl = track_dist(line[1])
-        tol_dl = tol * dl
 
         track, dist = [], []
         start_col, end_col = None, None
@@ -2032,7 +2030,8 @@ def track_dist(p): return norm(p - line[0])
                         elif col == end_col:
                             pts = [pts[0], line[-1]]
                         din, dout = track_dist(pts[0]), track_dist(pts[-1])
-                        if abs(dout - din) > tol_dl:
+                        col_tol = max(col.side_lengths) * tol
+                        if abs(dout - din) > col_tol:
                             track.append((col, pts[0], pts[-1]))
                             dist.append(din)
 

tests/test_mulgrid.py

@@ -356,6 +356,16 @@ def test_column_track(self):
             self.assertTrue(np.allclose(t[0][1], line[0]))
             self.assertTrue(np.allclose(t[-1][2], line[1]))
 
+        # contrasting grid sizes:
+        dx = [1] * 50 + [2] * 25 + [5] * 20 + [10] * 20 + [100] * 6 + [1000] * 2
+        geo = mulgrid().rectangular(dx, [100]*5, [10])
+        line = [np.array([0, 0]), np.array([3000, 0])]
+        t = geo.column_track(line)
+        self.assertEqual(len(t), 123)
+        if (len(t) == 123):
+            self.assertTrue(np.allclose(t[0][1], line[0]))
+            self.assertTrue(np.allclose(t[-1][2], line[1]))
+
     def test_grid3d(self):
         """3D grid"""