Update insert_knot and add elevate_degree

- Update Example nurbs_curve.f90
- Update README.md

README.md

@@ -63,7 +63,8 @@ ford ford.yml
 - [x] Add `insert_knot()` method for curves.
 - [ ] Add `insert_knot()` method for surfaces and volumes.
 - [ ] Add `remove_knot()` method for curves, surfaces and volumes.
-- [ ] Add `elevate_degree()` method for curves, surfaces and volumes.
+- [x] Add `elevate_degree()` method for curves.
+- [ ] Add `elevate_degree()` method for surfaces and volumes.
 - [ ] Add `reduce_degree()` method for curves, surfaces and volumes.
 - [ ] Add `derivative()` method.
 - [ ] Add support for multiple patches.

example/nurbs_curve.f90

@@ -22,7 +22,7 @@ program example_nurbs_curve
 
     ! Define weights for the control points
     allocate(Wc(3))
-    Wc = [1.0_rk, 2.0_rk, 1.0_rk]
+    Wc = [1.0_rk, 2.0_rk, 0.3_rk]
 
     ! Define knot vector
     knot = [0.0_rk, 0.0_rk, 0.0_rk, 1.0_rk, 1.0_rk, 1.0_rk]
@@ -43,6 +43,22 @@ program example_nurbs_curve
     ! Export the generated curve to a VTK file
     call nurbs%export_Xg('vtk/nurbs_curve_Xg.vtk')
 
+    !-----------------------------------------------------------------------------
+    ! Refinements
+    !-----------------------------------------------------------------------------
+
+    ! Insert knots
+    call nurbs%insert_knot([0.25_rk, 0.75_rk])
+
+    ! Elevate the degree of the curve (2 times)
+    call nurbs%elevate_degree(2)
+
+    ! Export updated control points to a VTK file
+    call nurbs%export_Xc('vtk/nurbs_curve_Xc2.vtk')
+
+    ! Export the refined generated curve to a VTK file
+    call nurbs%export_Xg('vtk/nurbs_curve_Xg2.vtk')
+
     !-----------------------------------------------------------------------------
     ! Finalizing
     !-----------------------------------------------------------------------------