Fixing crashing bug when using Twist3.R[x,y,z]

Calling Twist3.Rx(0.5) results in a TypeError: 'float' object is not iterable error. The same error is experienced for Twist.Ry and Twist.Rz as well.

This change converts the output of base.getunit to a vector if a scalar value is provided for theta.

Author: suddrey-qut

spatialmath/twist.py

@@ -554,7 +554,7 @@ def Rx(cls, theta, unit='rad'):
         :seealso: :func:`~spatialmath.base.transforms3d.trotx`
         :SymPy: supported
         """
-        return cls([np.r_[0,0,0,x,0,0] for x in base.getunit(theta, unit=unit)])
+        return cls([np.r_[0,0,0,x,0,0] for x in base.getvector(base.getunit(theta, unit=unit)_])
 
     @classmethod
     def Ry(cls, theta, unit='rad', t=None):
@@ -585,7 +585,7 @@ def Ry(cls, theta, unit='rad', t=None):
         :seealso: :func:`~spatialmath.base.transforms3d.troty`
         :SymPy: supported
         """
-        return cls([np.r_[0,0,0,0,x,0] for x in base.getunit(theta, unit=unit)])
+        return cls([np.r_[0,0,0,0,x,0] for x in base.getvector(base.getunit(theta, unit=unit))])
 
     @classmethod
     def Rz(cls, theta, unit='rad', t=None):
@@ -616,7 +616,7 @@ def Rz(cls, theta, unit='rad', t=None):
         :seealso: :func:`~spatialmath.base.transforms3d.trotz`
         :SymPy: supported
         """
-        return cls([np.r_[0,0,0,0,0,x] for x in base.getunit(theta, unit=unit)])
+        return cls([np.r_[0,0,0,0,0,x] for x in base.getvector(base.getunit(theta, unit=unit))])
 
     @classmethod
     def Tx(cls, x):
@@ -1714,4 +1714,4 @@ def _repr_pretty_(self, p, cycle):
 
     # import pathlib
 
-    # exec(open(pathlib.Path(__file__).parent.parent.absolute() / "tests" / "test_twist.py").read())  # pylint: disable=exec-used
+    # exec(open(pathlib.Path(__file__).parent.parent.absolute() / "tests" / "test_twist.py").read())  # pylint: disable=exec-used