twinx and plot_date about matplotlib HOT 3 CLOSED

>>> import matplotlib.pyplot as plt
>>> import matplotlib.dates
>>> import datetime
>>> 
>>> t = datetime.datetime.now().date()
>>> left_varr = range(10)
>>> right_varr = range(10)
>>> right_varr.reverse()
>>> tarr = matplotlib.dates.date2num([t + datetime.timedelta(days=i) for i in right_varr])
>>> fig = plt.figure()
>>> ax1 = fig.add_subplot(1,1,1)
>>> 
>>> ax2 = ax1.twinx()
>>> ax2.plot_date(tarr, right_varr)
[<matplotlib.lines.Line2D object at 0x1025374d0>]
>>> fig.canvas.draw()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/backends/backend_agg.py", line 433, in draw
    self.figure.draw(self.renderer)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/figure.py", line 927, in draw
    func(*args)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/axes.py", line 1998, in draw
    a.draw(renderer)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/artist.py", line 55, in draw_wrapper
    draw(artist, renderer, *args, **kwargs)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/axis.py", line 1047, in draw
    ticks_to_draw = self._update_ticks(renderer)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/axis.py", line 937, in _update_ticks
    tick_tups = [ t for t in self.iter_ticks()]
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/axis.py", line 884, in iter_ticks
    majorLocs = self.major.locator()
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/dates.py", line 752, in __call__
    self.refresh()
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/dates.py", line 761, in refresh
    dmin, dmax = self.viewlim_to_dt()
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/dates.py", line 533, in viewlim_to_dt
    return num2date(vmin, self.tz), num2date(vmax, self.tz)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/dates.py", line 292, in num2date
    if not cbook.iterable(x): return _from_ordinalf(x, tz)
  File "/Users/pelson/dev/matplotlib/lib/matplotlib/dates.py", line 206, in _from_ordinalf
    dt = datetime.datetime.fromordinal(ix)
ValueError: ordinal must be >= 1