My objective is to plot live data on multiple y axes(different ranges). The following code worked with 2 y axes but when I added a 3rd one, the browser was just a blank.An earlier basic bokeh plot with 4 y axes worked fine but this server version is not working.I dont know what mistake I am doing,please guide me.
The following code plots 2 temporary points then a 3rd permanent point. Uses ‘patch’ and ‘stream’ from ColumnDataSource to achieve this.
Please download the attached files.
from bokeh.io import curdoc
from bokeh.models import ColumnDataSource
from bokeh.plotting import figure
from bokeh.models import LinearAxis, Range1d
import numpy as np
def plotcharts(source,x,a,b,c):
fig=figure(y_range=(0, 500))
fig.circle(source=source, x=x,y=a,size=12,color='red')
fig.extra_y_ranges = {"foo1": Range1d(start=0, end=50)}
fig.circle(source=source,x=x, y=b, size=12, color="blue",
y_range_name="foo1")
fig.add_layout(LinearAxis(y_range_name="foo1"), 'left')
# configure 3rd axis
fig.extra_y_ranges = {"foo2": Range1d(start=0, end=25)}
fig.circle(source=source, x=x, y=c, color="magenta",
y_range_name="foo2")
fig.add_layout(LinearAxis(y_range_name="foo2"), 'right')
return fig
count=(-1)
dct=dict(x=[],a=[],b=[],c=[])
#Just a and b work fine but when 3rd axis c was added it doesnt !
source=ColumnDataSource(dct)
fig=plotcharts(source,'x','a','b','c') #c==3rd axis
def update_data():
global count
count=count+1
y1 = np.random.randint(low=0, high=500)
y2 = np.random.randint(low=0, high=50)
y3 = np.random.randint(low=0, high=25) #y3==3rd axis
if count%3==0:
new_data = {
'x': [count/3],
'a': [y1],
'b': [y2],
'c': [y3] #c==3rd axis
}
source.stream(new_data,rollover=20)
else:
l = len(df['a'])
new_data = {
'a': [(l - 1,y1)],
'b': [(l - 1, y2)],
'c': [(l - 1, y3)] #c==3rd axis
}
source.patch(new_data)
curdoc().add_root(fig)
curdoc().add_periodic_callback(update_data,1000)
