test__geometric_intersection.py 文件源码

def test_quadratic(self):
        from bezier import _curve_helpers

        nodes = np.asfortranarray([
            [0.0, 0.0],
            [1.0, 1.0],
            [5.0, 6.0],
        ])
        # NOTE: This is hand picked so that
        #             d Nodes = [1, 1], [4, 5]
        #           d^2 Nodes = [3, 4]
        #       so that sqrt(3^2 + 4^2) = 5.0
        error_val = self._call_function_under_test(nodes)
        expected = 0.125 * 2 * 1 * 5.0
        self.assertEqual(error_val, expected)

        # For a degree two curve, the 2nd derivative is constant
        # so by subdividing, our error should drop by a factor
        # of (1/2)^2 = 4.
        left_nodes, right_nodes = _curve_helpers.subdivide_nodes(nodes)
        error_left = self._call_function_under_test(left_nodes)
        error_right = self._call_function_under_test(right_nodes)
        self.assertEqual(error_left, 0.25 * expected)
        self.assertEqual(error_right, 0.25 * expected)