How can I build plotly heatmap faster?

Question

I am trying to make a heatmap plot with slider using python plotly

Here is my sample code.

import numpy as np
import plotly as py
import pandas as pd
from PIL import Image

from plotly.subplots import make_subplots
import plotly.express as px
import plotly.graph_objects as go

import time

# make test histogram. np.array
histogram_meter = np.random.randint(0, 500,(50,100))

# get figures
fig = go.Figure()

# add sliders
cnt_max = int(histogram_meter.max())           

if(len(tmp_histogram) != 0):
    avg = histogram_meter[histogram_meter != 0].mean()
    std = histogram_meter[histogram_meter != 0].std()
else:
    avg = 0
    std = 0
step_max  = int(avg + 2 *std)  # 2-sigma                      
step_list = list(range(0, step_max))
time_check = time.time()
for step in step_list:
    fig.add_trace(
        go.Heatmap(
            visible=False,
            z=histogram_meter,
            zsmooth='fast',
            connectgaps=True,
            colorscale=[[0, 'rgba(0, 0, 255,0)'],
                        [0.1, 'rgba(0, 0, 255,1)'],
                        [1.0, 'rgba(255, 0, 0, 1.0)']],
            zmin=0,
            zmax=step
        )
    )

print("time check for drawing heatmap = ", time.time()-time_check)
time_check = time.time()
fig.data[step_max-1].visible = True

time_check = time.time()
steps = []
for i in range(step_max):  # range(len(fig.data)):
    # time_check2 = time.time()
    step = dict(
        method="update",
        args=[
            {"visible": [False]*len(fig.data)},
            {"title": "Threshold switched to : " + str(i)}],  # layout attribute
        label=" {}".format(i)
    )
    # Toggle i'th trace to "visible"
    step["args"][0]["visible"][i] = True
    steps.append(step)
    # print("time check add 1-step to slider = ", time.time()-time_check2)

print("time check for drawing slider = ", time.time()-time_check)
time_check = time.time()

sliders = [dict(
    active=step_max-1,
    currentvalue={"prefix": "Threshold: "},
    pad={"t": 50},
    steps=steps
)]
fig.update_layout(sliders=sliders)
print("time check for update_layout(slider) = ", time.time()-time_check)
time_check = time.time()

# configure color bar
colorbar = dict(
    title="count",
    thicknessmode="pixels", thickness=50,
    lenmode="pixels", len=400,
    yanchor="top", y=1,
    ticks="outside", ticksuffix="count",
    dtick=5
)
fig.update_layout(coloraxis_colorbar=colorbar)
fig.update_layout(font_size=20)
print("time check for update_layout(color_bar) = ", time.time()-time_check)
time_check = time.time()
fig.show()

print("end")

when number of sample data is 100,

time check for drawing heatmap =  0.15591144561767578
time check for drawing slider =  0.0
time check for update_layout =  0.0879526138305664
time check for update_layout(color_bar) =  0.1019136905670166

and plot is generated in a second.

when number of sample data is 500,

time check for drawing heatmap =  0.4447438716888428
time check for drawing slider =  0.007018089294433594
time check for update_layout(slider) =  0.47070741653442383
time check for update_layout(color_bar) =  0.08794975280761719

In this case, it takes too long for the heatplot to be drawn. (Exactly, the heatmap plot appears to be still loading. )

I think, there are some problem in my code. Is there any way to improve my code?

Can you help me??

How can I build plotly heatmap faster?

0 Answers