Changeset 5932 for anuga_core/source/anuga/utilities/polygon.py

Timestamp:

Nov 10, 2008, 5:21:16 PM (16 years ago)

Author:

rwilson

Message:

Make line intersection function accept rtol/atol values, and pass them through to all subsequent comparisons.

File:

• anuga_core/source/anuga/utilities/polygon.py (modified) (6 diffs)

anuga_core/source/anuga/utilities/polygon.py

@@ -18 +18 @@
 
 
-def point_on_line(point, line, rtol=0.0, atol=0.0):
+def point_on_line(point, line, rtol=1.0e-5, atol=1.0e-8):
     """Determine whether a point is on a line segment
 
@@ -31 +31 @@
     """
 
-    # FIXME(Ole): Perhaps make defaults as in allclose: rtol=1.0e-5, atol=1.0e-8
-
     point = ensure_numeric(point)
     line = ensure_numeric(line)
@@ -47 +45 @@
 
 
-def intersection(line0, line1):
+def intersection(line0, line1, rtol=1.0e-5, atol=1.0e-8):
     """Returns intersecting point between two line segments or None
     (if parallel or no intersection is found).
@@ -89 +87 @@
     u1 = (x2-x0)*(y1-y0) - (y2-y0)*(x1-x0)
         
-    if allclose(denom, 0.0):
+    if allclose(denom, 0.0, rtol=rtol, atol=atol):
         # Lines are parallel - check if they coincide on a shared a segment
 
-        if allclose( [u0, u1], 0.0 ):
+        if allclose( [u0, u1], 0.0, rtol=rtol, atol=atol ):
             # We now know that the lines if continued coincide
             # The remaining check will establish if the finite lines share a segment
@@ -99 +97 @@
             line1_starts_on_line0 = line1_ends_on_line0 = False
                 
-            if point_on_line([x0, y0], line1):
+            if point_on_line([x0, y0], line1, rtol=rtol, atol=atol):
                 line0_starts_on_line1 = True
 
-            if point_on_line([x1, y1], line1):
+            if point_on_line([x1, y1], line1, rtol=rtol, atol=atol):
                 line0_ends_on_line1 = True
  
-            if point_on_line([x2, y2], line0):
+            if point_on_line([x2, y2], line0, rtol=rtol, atol=atol):
                 line1_starts_on_line0 = True
 
-            if point_on_line([x3, y3], line0):
+            if point_on_line([x3, y3], line0, rtol=rtol, atol=atol):
                 line1_ends_on_line0 = True                               
 
@@ -161 +159 @@
 
         # Sanity check - can be removed to speed up if needed
-        assert allclose(x, x2 + u1*(x3-x2))
-        assert allclose(y, y2 + u1*(y3-y2))        
+        assert allclose(x, x2 + u1*(x3-x2), rtol=rtol, atol=atol)
+        assert allclose(y, y2 + u1*(y3-y2), rtol=rtol, atol=atol)        
 
         # Check if point found lies within given line segments