Cannot display DynamicMap inside a JupyterLab notebook

Hello,

I can’t seem to figure out how to run the Game of Life example inside a notebook in JupyterLab 0.32.1 with holoviews 1.10.4, bokeh 0.12.15.

The JupyterLab is running on localhost:8888.

First cell

import numpy as np
import holoviews as hv

from holoviews.streams import Tap, Counter
from scipy.signal import convolve2d

renderer = hv.renderer('bokeh')

diehard = [[0, 0, 0, 0, 0, 0, 1, 0],
           [1, 1, 0, 0, 0, 0, 0, 0],
           [0, 1, 0, 0, 0, 1, 1, 1]]

boat = [[1, 1, 0],
        [1, 0, 1],
        [0, 1, 0]]

r_pentomino = [[0, 1, 1],
               [1, 1, 0],
               [0, 1, 0]]

beacon = [[0, 0, 1, 1],
          [0, 0, 1, 1],
          [1, 1, 0, 0],
          [1, 1, 0, 0]]

acorn = [[0, 1, 0, 0, 0, 0, 0],
         [0, 0, 0, 1, 0, 0, 0],
         [1, 1, 0, 0, 1, 1, 1]]

spaceship = [[0, 0, 1, 1, 0],
             [1, 1, 0, 1, 1],
             [1, 1, 1, 1, 0],
             [0, 1, 1, 0, 0]]

block_switch_engine = [[0, 0, 0, 0, 0, 0, 1, 0],
                       [0, 0, 0, 0, 1, 0, 1, 1],
                       [0, 0, 0, 0, 1, 0, 1, 0],
                       [0, 0, 0, 0, 1, 0, 0, 0],
                       [0, 0, 1, 0, 0, 0, 0, 0],
                       [1, 0, 1, 0, 0, 0, 0, 0]]

glider = [[1, 0, 0], [0, 1, 1], [1, 1, 0]]

unbounded = [[1, 1, 1, 0, 1],
            [1, 0, 0, 0, 0],
            [0, 0, 0, 1, 1],
            [0, 1, 1, 0, 1],
            [1, 0, 1, 0, 1]]

shapes = {'Glider': glider, 'Block Switch Engine': block_switch_engine,
          'Spaceship': spaceship, 'Acorn': acorn, 'Beacon': beacon,
          'Diehard': diehard, 'Unbounded': unbounded}

def step(X):
    nbrs_count = convolve2d(X, np.ones((3, 3)), mode='same', boundary='wrap') - X
    return (nbrs_count == 3) | (X & (nbrs_count == 2))

def update(pattern, counter, x, y):
    if counter:
        img.data = step(img.data)
    if x and y:
        pattern = np.array(shapes[pattern])
        r, c = pattern.shape
        y, x = img.sheet2matrixidx(x,y)
        img.data[y:y+r,x:x+c] = pattern[::-1]
    return hv.Image(img)

title = 'Game of Life - Tap to place pattern, Doubletap to clear'
opts =  {
    'style': {'cmap': 'gray', 'toolbar': False, },
    'plot' : {'height': 400, 'width': 800, 'title_format': '{label}',
              'xaxis': None, 'yaxis': None}
}
img = hv.Image(np.zeros((100, 200), dtype=np.uint8))
counter, tap = Counter(transient=True), Tap(transient=True)
pattern_dim = hv.Dimension('Pattern', values=sorted(shapes.keys()))
dmap = hv.DynamicMap(update, kdims=[pattern_dim], streams=[counter, tap])

# doc = renderer.server_doc(dmap.redim.range(z=(0, 1)).opts(**opts))
# doc.title = 'Game of Life'

app = renderer.app(dmap.redim.range(z=(0, 1)).opts(**opts), show=True, websocket_origin='localhost:8888')

gives: INFO:bokeh.server.server:Starting Bokeh server version 0.12.15 (running on Tornado 5.0.2)

Second cell:

dmap.periodic(0.05)

gives no output – it keeps running and upon interruption, it is clear that it can’t connect:

KeyboardInterrupt                         Traceback (most recent call last)
<ipython-input-3-8f5136ab6c88> in <module>()
----> 1 dmap.periodic(0.05)

.../python3.6/site-packages/holoviews/core/spaces.py in __call__(self, period, count, param_fn, timeout, block)
    692         instance = self._periodic_util(period, count, inner,
    693                                        timeout=timeout, block=block)
--> 694         instance.start()
    695         self.instance= instance
    696 

.../python3.6/site-packages/holoviews/core/util.py in start(self)
    174             super(periodic,self).start()
    175         else:
--> 176             self.run()
    177 
    178     def stop(self):
.../python3.6/site-packages/holoviews/core/util.py in run(self)
    190         while not self.completed:
    191             if self.block:
--> 192                 time.sleep(self.period)
    193             else:
    194                 self._completed.wait(self.period)

KeyboardInterrupt:

Any help would be greatly appreciated 😃

[philippjfr]

To be able to display it in a notebook you need to make sure to load the extension first with:

hv.extension('bokeh')

After that the changes you made to display as an app inside the notebook seem to work for me.

[philippjfr]

A descriptive error message (instead of an infinite loop) would help a lot, if it’s possible to detect at all.

It’s not detectable unfortunately, doing it without loading the extension is perfectly valid since it just serves the app on a different port, which you could access in a new browser window.