Fixes typo in integral

TobiaMarcucci · Oct 5, 2024 · 768c351 · 768c351
1 parent e2088d1
commit 768c351
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Showing 3 changed files with 15 additions and 11 deletions.
diff --git a/pybezier/bezier_curve.py b/pybezier/bezier_curve.py
@@ -98,7 +98,7 @@ def derivative(self) -> Self:
         return BezierCurve(points, self.initial_time, self.final_time)
 
     def integral(self, initial_condition : np.ndarray | None = None) -> Self:
-        points = self.points * self.duration / self.degree
+        points = self.points * self.duration / (self.degree + 1)
         points = np.vstack([np.zeros(self.dimension), points])
         points = np.cumsum(points, axis=0)
         if initial_condition is not None:

diff --git a/tests/test_bezier_curve.py b/tests/test_bezier_curve.py
@@ -119,12 +119,14 @@ def test_integral(self):
         initial_conditions = [None, np.ones(self.curve.dimension)]
         for initial_condition in initial_conditions:
             integral = self.curve.integral(initial_condition)
-            value = 0 if initial_condition is None else initial_condition
-            np.testing.assert_array_almost_equal(integral(self.initial_time), value)
-            time_step = 1e-6
+            value = integral(self.initial_time)
+            target_value = 0 if initial_condition is None else initial_condition
+            np.testing.assert_array_almost_equal(value, target_value)
+            time_step = 1e-3
             for time in np.linspace(self.initial_time, self.final_time - time_step):
-                numerical_integral = integral(time) + time_step * self.curve(time)
-                np.testing.assert_array_almost_equal(integral(time + time_step), numerical_integral)
+                value = self.curve(time + time_step / 2)
+                target_value = (integral(time + time_step) - integral(time)) / time_step
+                np.testing.assert_array_almost_equal(value, target_value)
 
     def test_domain_split(self):
         split_time = (self.initial_time + self.final_time) / 2

diff --git a/tests/test_composite_bezier_curve.py b/tests/test_composite_bezier_curve.py
@@ -130,12 +130,14 @@ def test_integral(self):
         initial_conditions = [None, np.ones(self.composite_curve.dimension)]
         for initial_condition in initial_conditions:
             integral = self.composite_curve.integral(initial_condition)
-            value = 0 if initial_condition is None else initial_condition
-            np.testing.assert_array_almost_equal(integral(self.initial_time), value)
-            time_step = 1e-6
+            value = integral(self.initial_time)
+            target_value = 0 if initial_condition is None else initial_condition
+            np.testing.assert_array_almost_equal(value, target_value)
+            time_step = 1e-3
             for time in np.linspace(self.initial_time, self.final_time - time_step):
-                numerical_integral = integral(time) + time_step * self.composite_curve(time)
-                np.testing.assert_array_almost_equal(integral(time + time_step), numerical_integral)
+                value = self.composite_curve(time + time_step / 2)
+                target_value = (integral(time + time_step) - integral(time)) / time_step
+                np.testing.assert_array_almost_equal(value, target_value)
 
     def test_knot_points(self):
         for i, point in enumerate(self.composite_curve.knot_points()):