BUG fixed sampling from Categorical

Author: superbobry

pymc3/distributions/discrete.py

@@ -345,7 +345,7 @@ def __init__(self, p, *args, **kwargs):
 
     def random(self, point=None, size=None, repeat=None):
         p, k = draw_values([self.p, self.k], point=point)
-        return generate_samples(partial(np.random.choice, k),
+        return generate_samples(partial(np.random.choice, np.arange(k)),
                                 p=p,
                                 broadcast_shape=p.shape[:-1] or (1,),
                                 dist_shape=self.shape,