temporarily revert problematic knot_removal fix

Author: orbingol

geomdl/helpers.py

@@ -665,7 +665,6 @@ def knot_removal(degree, knotvector, ctrlpts, u, **kwargs):
         temp = [[] for _ in range((2 * degree) + 1)]
 
     # Loop for Eqs 5.28 & 5.29
-    tx = 1
     for t in range(0, num):
         temp[0] = ctrlpts[first - 1]
         temp[last - first + 2] = ctrlpts[last + 1]
@@ -721,29 +720,28 @@ def knot_removal(degree, knotvector, ctrlpts, u, **kwargs):
                 ctrlpts_new[j] = temp[j - first + 1]
                 i += 1
                 j -= 1
-            tx += 1
 
         # Update indices
         first -= 1
         last += 1
 
+    # Fix indexing
+    t += 1
+
     # Shift control points (refer to p.183 of The NURBS Book, 2nd Edition)
-    if tx > 1:
-        j = int((2 * r - s - degree) / 2)  # first control point out
-        i = j
-        for k in range(1, tx):
-            if k % 2 == 1:
-                i += 1
-            else:
-                j -= 1
-        for k in range(i + 1, len(ctrlpts)):
-            ctrlpts_new[j] = ctrlpts_new[k]
-            j += 1
+    j = int((2 * r - s - degree) / 2)  # first control point out
+    i = j
+    for k in range(1, t):
+        if k % 2 == 1:
+            i += 1
+        else:
+            j -= 1
+    for k in range(i + 1, len(ctrlpts)):
+        ctrlpts_new[j] = ctrlpts[k]
+        j += 1
 
-        # Slice to get the new control points
-        ctrlpts_new = ctrlpts_new[0 : -(tx - 1)]
-    else:
-        raise GeomdlException("Cannot remove knot: " + str(u))
+    # Slice to get the new control points
+    ctrlpts_new = ctrlpts_new[0:-t]
 
     return ctrlpts_new