Seaborn Violin plot error No loop for unfunc add
I had tried the suggestion from @foxthatruns's answer to no avail. I found that changing my numeric column to float64 solved the problem (reference).

df['my_column']=df['my_column'].astype('float64')

This was done with Python 3.7, seaborn 0.9.0, numpy 1.16.4.