New little function to normalise vectors. Sick of duplicating this code

everywhere.

fsl/utils/transform.py

@@ -22,6 +22,14 @@ spaces. The following functions are provided:
    axisBounds
    flirtMatrixToSform
    sformToFlirtMatrix
+
+And a few more functions are provided for working with vectors:
+
+.. autosummary::
+   :nosignatures:
+
+   veclength
+   normalise
 """
 
 import numpy        as np
@@ -45,6 +53,16 @@ def concat(*xforms):
     return result
 
 
+def veclength(vec):
+    """Returns the length of the given vector. """
+    return np.sqrt(np.dot(vec, vec))
+
+
+def normalise(vec):
+    """Normalises the given vector to unit length. """
+    return vec / veclength(vec)
+
+
 def scaleOffsetXform(scales, offsets):
     """Creates and returns an affine transformation matrix which encodes
     the specified scale(s) and offset(s).