add tests

Author: jcao-bdai

spatialmath/base/quaternions.py

@@ -549,7 +549,7 @@ def r2q(
     check: Optional[bool] = False,
     tol: float = 20,
     order: Optional[str] = "sxyz",
-    shortest: bool = True,
+    shortest: bool = False,
 ) -> UnitQuaternionArray:
     """
     Convert SO(3) rotation matrix to unit-quaternion
@@ -564,7 +564,7 @@ def r2q(
         'xyzs'. Defaults to 'sxyz'.
     :type order: str
     :param shortest: ensures the quaternion has non-negative scalar part.
-    :type shortest: bool, default to True
+    :type shortest: bool, default to False
     :return: unit-quaternion as Euler parameters
     :rtype: ndarray(4)
     :raises ValueError: for non SO(3) argument

spatialmath/base/transforms2d.py

@@ -943,6 +943,10 @@ def trinterp2(start, end, s, shortest: bool = True):
 
             th0 = math.atan2(start[1, 0], start[0, 0])
             th1 = math.atan2(end[1, 0], end[0, 0])
+            if shortest:
+                delta = (th1 - th0 + math.pi) % (math.pi * 2) - math.pi
+                delta = delta + math.pi * 2 if delta < -math.pi else delta
+                th1 = th0 + delta
 
             p0 = transl2(start)
             p1 = transl2(end)

spatialmath/baseposematrix.py

@@ -434,7 +434,7 @@ def interp(self, end: Optional[bool] = None, s: Union[int, float] = None, shorte
         if self.N == 2:
             # SO(2) or SE(2)
             return self.__class__(
-                [smb.trinterp2(start=self.A, end=end, s=_s) for _s in s]
+                [smb.trinterp2(start=self.A, end=end, s=_s, shortest=shortest) for _s in s]
             )
 
         elif self.N == 3:

tests/base/test_quaternions.py

@@ -131,6 +131,13 @@ def test_rotation(self):
         )
         nt.assert_array_almost_equal(qvmul([0, 1, 0, 0], [0, 0, 1]), np.r_[0, 0, -1])
 
+        large_rotation = math.pi + 0.01
+        q1 = r2q(tr.rotx(large_rotation), shortest=False)
+        q2 = r2q(tr.rotx(large_rotation), shortest=True)
+        self.assertLess(q1[0], 0)
+        self.assertGreater(q2[0], 0)
+        self.assertTrue(qisequal(q1=q1, q2=q2, unitq=True))
+
     def test_slerp(self):
         q1 = np.r_[0, 1, 0, 0]
         q2 = np.r_[0, 0, 1, 0]

tests/test_pose2d.py

@@ -456,6 +456,16 @@ def test_interp(self):
         array_compare(I.interp(TT, s=1), TT)
         array_compare(I.interp(TT, s=0.5), SE2(1, -2, 0.3))
 
+        R1 = SO2(math.pi - 0.1)
+        R2 = SO2(-math.pi + 0.2)
+        array_compare(R1.interp(R2, s=0.5, shortest=False), SO2(0.05))
+        array_compare(R1.interp(R2, s=0.5, shortest=True), SO2(-math.pi + 0.05))
+
+        T1 = SE2(0, 0, math.pi - 0.1)
+        T2 = SE2(0, 0, -math.pi + 0.2)
+        array_compare(T1.interp(T2, s=0.5, shortest=False), SE2(0, 0, 0.05))
+        array_compare(T1.interp(T2, s=0.5, shortest=True), SE2(0, 0, -math.pi + 0.05))
+
     def test_miscellany(self):
         TT = SE2(1, 2, 0.3)