Thread: [Matplotlib-users] dates fail after upgrade

I upgraded to matplotlib-0.87.4 Now I receive an error like the following every time I try to use matplotlib.dates. The following error messages were generated when I tried to run matplotlib-0.87.4/examples/date_demo1.py
Any Idea on how I can get dates working again?
(I am running the 2.6.17.6 kernel on a 64-bit linux system)
Example:
matplotlib-0.87.4/examples]$ python date_demo1.py
Traceback (most recent call last):
 File "/usr/lib64/python2.4/site-packages/matplotlib/backends/backend_gtk.py", line 284, in expose_event
 self._render_figure(self._pixmap, w, h)
 File "/usr/lib64/python2.4/site-packages/matplotlib/backends/backend_gtkagg.py", line 73, in _render_figure
 FigureCanvasAgg.draw(self)
 File "/usr/lib64/python2.4/site-packages/matplotlib/backends/backend_agg.py", line 391, in draw
 self.figure.draw(renderer)
 File "/usr/lib64/python2.4/site-packages/matplotlib/figure.py", line 532, in draw
 for a in self.axes: a.draw(renderer)
 File "/usr/lib64/python2.4/site-packages/matplotlib/axes.py", line 1045, in draw
 a.draw(renderer)
 File "/usr/lib64/python2.4/site-packages/matplotlib/axis.py", line 548, in draw
 majorLabels = [self.major.formatter(val, i) for i, val in enumerate(majorLocs)]
 File "/usr/lib64/python2.4/site-packages/matplotlib/dates.py", line 247, in __call__
 dt = num2date(x, self.tz)
 File "/usr/lib64/python2.4/site-packages/matplotlib/dates.py", line 205, in num2date
 if not iterable(x): return _from_ordinalf(x, tz)
 File "/usr/lib64/python2.4/site-packages/matplotlib/dates.py", line 156, in _from_ordinalf
 hour, remainder = divmod(24*remainder, 1)
ValueError: need more than 0 values to unpack
Traceback (most recent call last):
Richard

On Friday 28 July 2006 17:19, Richard Ruth wrote:
> I upgraded to matplotlib-0.87.4 Now I receive an error like the following
> every time I try to use matplotlib.dates. The following error messages
> were generated when I tried to run matplotlib-0.87.4/examples/date_demo1.py
>
> Any Idea on how I can get dates working again?
> (I am running the 2.6.17.6 kernel on a 64-bit linux system)
Richard,
in matplotlib/dates.py, change line 155 from
remainder = x - ix
to
remainder = float(x) - ix
The problem is that matplotlib uses numpy arrays for the xaxis. As you have a 
64b system, the arrays are in float64scalars, that divmod doesn't know how to 
process (unless you have a very recent of numpy). The trick above forces a 
downcasting of float64scalar to float32scalar, divmod can now work.

>>>>> "PGM" == PGM <pgm...@gm...> writes:
 PGM> Richard, in matplotlib/dates.py, change line 155 from
 PGM> remainder = x - ix to remainder = float(x) - ix
Thanks for th tip -- I'll commit this to svn.
JDH