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matplotlib dynamic plotting #7759
Description
Hi, after computer change, matplotlib don't work dynamically.
Before, it was able to update the figure at each iteration of a loop. Today only the last data are plotted.
Configuration :
HP zBook 15 G3 with NVidia Quadro
###Bug report
Bug summary
A figure inside a loop are not updated at each step
Code for reproduction
import matplotlib.pyplot as plt
import numpy as np
x = np.arange(128)
plt.figure(1)
plt.ion()
plt.hold(False)
for it in range(5):
plt.plot(x, x+it)
plt.draw()
plt.ioff()
plt.show()Expected outcome
- I expect to see one plot at each step of the for loop
Matplotlib version
1.5.1
Python version
3.5.2
OS
Ubuntu 16.04 LTS
- All of them had been installed from Ubuntu repository using synaptic
Activity
petehuang commented on Jan 7, 2017
I think you may need to add plt.pause(0.01) after plt.draw() - can you try that?
MpCamp commented on Jan 7, 2017
petehuang commented on Jan 7, 2017
I'm entirely the wrong person to ask for the "why", but I'm glad it works! I just shuttled around StackOverflow for the answer :)
tacaswell commented on Jan 7, 2017
'why' is a bit of a long question (see #4779 for an old PR trying to document all of the details). In very short, we made many of the GUI embedding more asynchronous, that is calling plt.draw calls fig.canvas.draw_idle() which asks the GUI to re-render the figure. If you never turn control over to the GUI event loop to process it's events, then it does not have a chance to update it's self (you will also note that while your code is running you can not pan/zoom the figure).
Doing
should do what you want.
MpCamp commented on Jan 8, 2017
petehuang commented on Jan 8, 2017
👍
Should we close this?
MpCamp commented on Jan 8, 2017
maxgittelman commented on Oct 25, 2017
Hey guys, any idea on how to fix my equivalent MatplotlibDeprecationWarning. I realized I essentially have the exact same problem except on a larger scale?
I have set up a server that will read in live data and produce two 3d plots. You can run this simulated code below (instead of reading in the data from the client).
import matplotlib.pyplot as plt from threading import Thread, Lock, Condition import random, time, socket from mpl_toolkits.mplot3d import Axes3D import numpy as np class Plotter: def __init__(self): # temp list of data received by server self.data = [[] for i in range(3)] # threading variables self.mutex = Lock() self.points_received = 0 self.cv = Condition() # initialize figure self.fig = plt.figure() self.run_plot = False self.ax = self.fig.add_subplot(111, projection='3d') self.ax.set_xlim(0, 1) self.ax.set_ylim(0, 1) self.ax.set_zlim(0, 1) plt.ion() plt.show() # This just simulates reading from a socket. def data_listener(self): while True: time.sleep(1) with self.mutex: new_data = [random.random() for i in range(3)] # append new data to be plotted and check max/min to update axes limits for axis in range(3): self.data[axis].append(new_data[axis]) def sub_plot(self): # wait until ready, <Enter> is pressed self.cv.acquire() while not self.run_plot: self.cv.wait() # I think this causes the plot to not respond before hitting <Enter> self.cv.release() while self.run_plot: time.sleep(0.01) with self.mutex: try: # add data and clear graph self.ax.scatter(self.data[0], self.data[1], self.data[2]) self.data = [[] for i in range(3)] plt.pause(0.000001) # self.fig.canvas.flush_events() except: print ("error") def cmdline_input(self): # Start then End Plot for status in ["start", "end"]: text_start = raw_input("Hit <Enter> to " + status + " plotting") while text_start != "": print "Wrong input" text_start = raw_input("Hit <Enter> to " + status + " plotting") self.cv.acquire() if status == "start": self.run_plot = True elif status == "end": self.run_plot = False self.cv.notify() self.cv.release() def run(self): d = Thread(target=self.data_listener) d.start() # start cmdline input c_start = Thread(target=self.cmdline_input) c_start.start() # subplot self.sub_plot() if __name__ == '__main__': p = Plotter() p.run()You guys have a better handle on how to fix this issue. Currently when I run the live plot (randomly sending over numbers), I can change the viewing angle with my cursor but I can't zoom in or out. I tried adding in self.fig.canvas.flush_events() after plt.pause(0.000001) but that didn't seem to functionally change anything.
I also noticed that when my plot isn't receiving live data, the window is unresponsive. I.e. If you try to maximize the window or change the window size the whole screen gets blurred. I have a feeling that this has something to do with me putting the plotting thread to sleep but maybe there's a simple fix?
tacaswell commented on Oct 26, 2017
This question is probably better sent to the mailing list (matplotlib-users@python.org ; you will have to subscribe to post).
#4779 may also be informative reading.