Holoviews dynamic map with datashader

holoviews_datashader.py

import datashader as ds
import holoviews as hv
from holoviews.operation.datashader import datashade
hv.extension('bokeh')

def scatter(dim1, dim2):
    def _scatter(data):
        return hv.Scatter(data, kdims=[dim1], vdims=[dim2], extents=(-10, -10, 10, 10))
    return _scatter

pipe = hv.streams.Pipe()

dmap = hv.DynamicMap(scatter('x', 'y'), streams=[pipe])
datashade(dmap)

import numpy as np

n = 100000
for i in np.arange(-np.pi, np.pi, 0.1):
    x = np.random.normal(loc=0, scale=1, size=n)
    y = i * x + np.random.normal(loc=0, scale=1, size=n)
    pipe.send({'x': x, 'y': y})