Add new transformation matrix Buw

bionc/bionc_numpy/transformation_matrix.py

@@ -132,7 +132,32 @@ def _transformation_matrix_Bwu(length: float, alpha: float, beta: float, gamma:
 
 
 def _transformation_matrix_Buw(length: float, alpha: float, beta: float, gamma: float) -> np.ndarray:
-    raise NotImplementedError("The transformation matrix Buw is not implemented yet.")
+    """
+    Create a transformation matrix of type Buw
+
+    Parameters
+    ----------
+    length: float
+        The length of the segment
+    alpha: float
+        The alpha angle
+    beta: float
+        The beta angle
+    gamma: float
+        The gamma angle
+
+    Returns
+    -------
+    numpy.ndarray
+        The transformation matrix
+    """
+    return np.array(
+        [
+            [1, length * cos(gamma), cos(beta)],
+            [0, length * np.sqrt(1 - cos(gamma) ** 2 - ((cos(alpha) - cos(gamma) * cos(beta)) / sin(beta)) ** 2), 0],
+            [0, length * (cos(alpha) - cos(gamma) * cos(beta) / sin(beta)), sin(beta)],
+        ]
+    )
 
 
 def _transformation_matrix_Bvw(length: float, alpha: float, beta: float, gamma: float) -> np.ndarray:

tests/test_transformation_matrix.py

@@ -76,8 +76,19 @@ def test_transformation_matrix_Bwu():
 
 
 def test_transformation_matrix_Buw():
-    with pytest.raises(NotImplementedError):
-        compute_transformation_matrix(TransformationMatrixType.Buw, length, alpha, beta, gamma)
+    result = compute_transformation_matrix(TransformationMatrixType.Buw, length, alpha, beta, gamma)
+    assert isinstance(result, np.ndarray)
+    assert result.shape == (3, 3)
+    np.testing.assert_almost_equal(
+        result,
+        np.array(
+            [
+                [1.0, 1.529684374568977, 0.8253356149096783],
+                [0.0, 0.9480367617186112, 0.0],
+                [0.0, -0.4807683268354297, 0.5646424733950354],
+            ]
+        ),
+    )
 
 
 def test_transformation_matrix_Bvw():
@@ -135,8 +146,16 @@ def test_segment_transformation_matrix(bionc_type):
     TestUtils.assert_equal(bbox.compute_transformation_matrix(matrix_type=TransformationMatrixType.Bwu), res_Bwu)
     TestUtils.assert_equal(bbox.compute_transformation_matrix(matrix_type="Bwu"), res_Bwu)
 
-    with pytest.raises(NotImplementedError):
-        bbox.compute_transformation_matrix(matrix_type=TransformationMatrixType.Buw)
+    res_Buw = np.array(
+        [
+            [1.0, 1.529684374568977, 0.8253356149096783],
+            [0.0, 0.9480367617186112, 0.0],
+            [0.0, -0.4807683268354297, 0.5646424733950354],
+        ]
+    )
+    TestUtils.assert_equal(bbox.compute_transformation_matrix(matrix_type=TransformationMatrixType.Buw), res_Buw)
+    TestUtils.assert_equal(bbox.compute_transformation_matrix(matrix_type="Buw"), res_Buw)
+
     with pytest.raises(NotImplementedError):
         bbox.compute_transformation_matrix(matrix_type=TransformationMatrixType.Bvw)
     with pytest.raises(NotImplementedError):