Matplotlib 1.3.1: plot (matrix ("1,2,3")) & # 8594; RuntimeError: Maximum recursion depth exceeded

I am working with python 2.7.5 using numpy. version : 1.7.1 matplotlib. version : 1.3.1 When I run "ipython2 --pylab" and execute the following code

x = matrix("1,2,3")
plot(x)

      

        
        
        
      

    

I am getting the error

[...]
/usr/lib/python2.7/site-packages/matplotlib/units.pyc in get_converter(self, x)
    146             except AttributeError:
    147                 # not a masked_array
--> 148                 converter = self.get_converter(xravel[0])
    149                 return converter
    150 
/usr/lib/python2.7/site-packages/numpy/matrixlib/defmatrix.py in __getitem__(self, index)
    303 
    304         try:
--> 305             out = N.ndarray.__getitem__(self, index)
    306         finally:
    307             self._getitem = False
RuntimeError: maximum recursion depth exceeded

      

        
        
        
      

    

The older version of matplotlib 1.3.0 did not have this error.

Any help is greatly appreciated! Thanx, Klaus.