Re: [matplotlib-devel] Problem with violinplot

[elmar w. <el...@ne...>]

having a look at seaborns ViolinPlotter class 
(https://github.com/mwaskom/seaborn/blob/master/seaborn/categorical.py), 
they explicit handle the special case of "no data" and "single unique 
datapoint" at line 580 ff.

Could something similar be added to matplotlibs violinplot?

On 04.07.2015 12:28, elmar werling wrote:
> from an end user point of view, matplotlibs violinplot should just do
> the same as seaborns violinplot.
>
>
> #####################################################################
> import numpy as np
> import matplotlib.pyplot as plt
> import seaborn as sns
>
> N = 100
> y1 = np.random.randn(N) + 3.0
> y2 = np.random.randn(N) * 5.0 + 50
> y3 = np.ones(N) * 100   # causing plt.violinplot problem
> y4 = np.arange(0)       # causing plt.violinplot problem
>
> #plt.violinplot([y1, y2, y3, y4])
>
> sns.violinplot(data=[y1, y2, y3, y4])
>
>
> On 03.07.2015 17:52, Thomas Caswell wrote:
>> The KDE computation code is a copy of the KDE code from scipy
>> (https://github.com/scipy/scipy/blob/master/scipy/stats/kde.py),  I
>> suggest raising this issue on their mailing list/github.
>>
>> I strongly suspect that violin plot should be doing data sanitation on
>> the way in or catching exceptions like this, but I am not familiar
>> enough with the math to be sure what it should do instead.
>>
>> Tom
>>
>> On Fri, Jul 3, 2015 at 11:41 AM elmar werling
>> <el...@ne...
>> <mailto:el...@ne...>> wrote:
>>
>>
>>      Hi all,
>>
>>      violinplot is crashing with singular matrix data. See example.
>>
>>      Is this behaviour for a singular matrix intended or just a bug?
>>
>>      Cheers
>>      Elmar
>>
>>
>>
>>      #####################################################
>>      import numpy as np
>>      import matplotlib.pyplot as plt
>>
>>      # data mimicing the
>>      # original cumsum data (may sum up to 100)
>>      N = 100
>>      y1 = np.random.randn(N) + 3.0
>>      y2 = np.random.randn(N) * 5.0 + 50
>>      y3 = np.ones(N) * 100   # data set causing violinplot problem
>>
>>      plt.violinplot([y1, y2, y3])
>>
>>      plt.boxplot([y1, y2, y3])  # ok
>>      plt.ylim(0,110)
>>
>>      #####################################################
>>
>>      OS:     Debian
>>      Anaconda 2.3.0 (64-bit)
>>      Python 2.7.10
>>      numpy 2.3.0
>>      matplotlib 1.4.3
>>
>>
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