I'm trying to animate two subplots, each with multiple lines. I am using Matplotlib, and I am using the FuncAnimation, which is used by many of the animation examples.
Using animation:
If I try to animate it, I only get the result of the first frame:
Without using animation:
If I manually call my update_lines function, it works fine.
Code:
Below is the full code (uncommenting the 3 indicated lines in main() works, but I would like to see it update in real-time, hence trying to use the animation).
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation
def make_subplots():
def setup_axes(axes):
for ax in axes:
ax.set_xbound(0, 100) # bound will change as needed.
ax.set_ylim(0, 1) # limit won't change automatically.
def make_lines(axes):
labels = ('a', 'b', 'c')
lines = []
for ax in axes:
ax_lines = []
for label in labels:
x, y = [0], [0]
line, = ax.plot(x, y, label=label) # comma for unpacking.
ax_lines.append((line, x, y))
lines.append(ax_lines)
return lines
fig, axes = plt.subplots(2, 1, sharex=True, sharey=True)
lines = make_lines(axes)
setup_axes(axes)
return fig, axes, lines
def make_data():
for i in xrange(100):
print 'make_data():', i
data = dict()
for label in ('a', 'b', 'c'):
from random import random
data[label] = random()
yield (i + 1, data)
def update_lines(data, lines):
print 'update_lines():', data, lines
updated_lines = []
for ax_lines in lines:
for line, x, y in ax_lines:
label = line.get_label()
x.append(data[0])
y.append(data[1][label])
line.set_data(x, y)
updated_lines.append(line)
def main():
fig, axes, lines = make_subplots()
# Uncomment these 3 lines, and it works!
# new_data = make_data()
# for data in new_data:
# update_lines(data, lines)
FuncAnimation(fig=fig,
func=update_lines,
frames=make_data,
fargs=(lines,),
interval=10,
blit=False)
plt.show()
if __name__ == '__main__':
main()
(Undocumented?) Hooks
So, I was digging around the source-code of matplotlib.animation.Animation, and I noticed these lines in the __init__() function:
# Clear the initial frame
self._init_draw()
# Instead of starting the event source now, we connect to the figure's
# draw_event, so that we only start once the figure has been drawn.
self._first_draw_id = fig.canvas.mpl_connect('draw_event', self._start)
Sounds familiar...
This looks right so far. The self._init_draw() call draws my first frame immediately. Then the animation-object hooks into the figure-object and waits for the figure to be shown before attempting to draw any more frames for the animation.
Eureka!
The keyword is: animation-object. Since I wasn't planning on using the animation instance later (for example, to draw a movie), I didn't assign it to a variable. In fact, I was being yelled at by pyflakes because Local variable '...' is assigned to but never used.
But because all of the functionality relies on the hook, when the canvas is finally shown I presume Python's garbage collection has removed the Animation instance---since it was never assigned to a variable---and therefore the animation can never be started.
The fix
Simply assign the instance FuncAnimation instance to a variable, and everything works as expected!
anim = FuncAnimation(fig=fig,
func=update_lines,
frames=make_data,
fargs=(lines,),
interval=10,
blit=False)
Related
I'm using the following code to produce an animation with matplotlib that is intended to visualize my experiments.
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import ArtistAnimation, PillowWriter
plt.rcParams['animation.html'] = 'jshtml'
def make_grid(X, description=None, labels=None, title_fmt="label: {}", cmap='gray', ncols=3, colors=None):
L = len(X)
nrows = -(-L // ncols)
frame_plot = []
for i in range(L):
plt.subplot(nrows, ncols, i + 1)
im = plt.imshow(X[i].squeeze(), cmap=cmap, interpolation='none')
if labels is not None:
color = 'k' if colors is None else colors[i]
plt.title(title_fmt.format(labels[i]), color=color)
plt.xticks([])
plt.yticks([])
frame_plot.append(im)
return frame_plot
def animate_step(X):
return X ** 2
n_splots = 6
X = np.random.random((n_splots,32,32,3))
Y = X
X_t = []
for i in range(10):
Y = animate_step(Y)
X_t.append((Y, i))
frames = []
for X, step in X_t:
frame = make_grid(X,
description="step={}".format(step),
labels=range(n_splots),
title_fmt="target: {}")
frames.append(frame)
anim = ArtistAnimation(plt.gcf(), frames,
interval=300, repeat_delay=8000, blit=True)
plt.close()
anim.save("test.gif", writer=PillowWriter())
anim
The result can be seen here:
https://i.stack.imgur.com/OaOsf.gif
It works fine so far, but I'm having trouble getting a shared xlabel to add a description for all of the 6 subplots in the animation. It is supposed to show what step the image is on, i.e. "step=5".
Since it is an animation, I cannot use xlabel or set_title (since it would be constant over the whole animation) and have to draw the text myself.
I've tried something along the lines of..
def make_grid(X, description=None, labels=None, title_fmt="label: {}", cmap='gray', ncols=3, colors=None):
L = len(X)
nrows = -(-L // ncols)
frame_plot = []
desc = plt.text(0.5, .04, description,
size=plt.rcparams["axes.titlesize"],
ha="center",
transform=plt.gca().transAxes
)
frame_plot.append(desc)
...
This, of course, won't work, because the axes are not yet created. I tried using the axis of another subplot(nrows, 1, nrows), but then the existing images are drawn over..
Does anyone have a solution to this?
Edit:
unclean, hacky solution for now:
Wait for the axes of the middle image of the last row to be created and use that for plotting the text.
In the for loop:
...
if i == int((nrows - 0.5) * ncols):
title = ax.text(0.25, -.3, description,
size=plt.rcParams["axes.titlesize"],
# ha="center",
transform=ax.transAxes
)
frame_plot.append(title)
...
To me, your case is easier to solve with FuncAnimation instead of ArtistAnimation, even if you already have access to the full list of data you want to show animated (see this thread for a discussion about the difference between the two functions).
Inspired from this FuncAnimation example, I wrote the code below that does what you needed (using the same code with ArtistAnimation and correct list of arguments does not work).
The main idea is to initialize all elements to be animated at the beginning, and to update them over the animation frames. This can be done for the text object (step_txt = fig.text(...)) in charge of displaying the current step, and for the images out from ax.imshow. You can then update whatever object you would like to see animated with this recipe.
Note that the technique works if you want the text to be an x_label or any text you choose to show. See the commented line in the code.
#!/Users/seydoux/anaconda3/envs/jupyter/bin/python
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation, PillowWriter
# parameters
n_frames = 10
n_splots = 6
n_cols = 3
n_rows = n_splots // n_cols
def update_data(x):
return x ** 2
# create all snapshots
snapshots = [np.random.rand(n_splots, 32, 32, 3)]
for _ in range(n_frames):
snapshots.append(update_data(snapshots[-1]))
# initialize figure and static elements
fig, axes = plt.subplots(2, 3)
axes = axes.ravel() # so we can access all axes with a single index
for i, ax in enumerate(axes):
ax.set_xticks([])
ax.set_yticks([])
ax.set_title("target: {}".format(i))
# initialize elements to be animated
step_txt = fig.text(0.5, 0.95, "step: 0", ha="center", weight="bold")
# step_txt = axes[4].set_xlabel("step: 0") # also works with x_label
imgs = list()
for a, s in zip(axes, snapshots[0]):
imgs.append(a.imshow(s, interpolation="none", cmap="gray"))
# animation function
def animate(i):
# update images
for img, s in zip(imgs, snapshots[i]):
img.set_data(s)
# update text
step_txt.set_text("step: {}".format(i))
# etc
anim = FuncAnimation(fig, animate, frames=n_frames, interval=300)
anim.save("test.gif", writer=PillowWriter())
Here is the output I got from the above code:
I'm trying to plot the time evolution of a function f(x,t). The data is stored in a file which has the following format:
1st row:f(0,0) f(0,1) f(0,2) ....f(0,N)
2nd row:f(1,0) f(1,1) f(1,2) ....f(1,N)
Mth row:f(M,0) f(M,1) f(M,2) ....f(M,N)
where N is the no: of points of the simulation box and M is the number of timesteps.
I used basic_animation by Jake Vanderplas (https://jakevdp.github.io/blog/2012/08/18/matplotlib-animation-tutorial/) to start with, the original example works fine as long as i put blit=False.
Then i tried to replace x by :
x= np.arange(0,192)
and y by the contents of the file mentioned above.
If i do just plt.plot(x,y), it does plot f(x,t) at a given time t, but I want the animation of f(x,t) in time.
set_data should accept 2 1Darrays and I've checked that len(x)=len(y).
But I get the following error message:
'RuntimeError: xdata and ydata must be the same length'
This is the code (in the future i would like to plot multiple functions):
"""
Modified Matplotlib Animation Example
original example:
email: vanderplas#astro.washington.edu
website: http://jakevdp.github.com
license: BSD
Feel free to use and modify this, but keep the above information.
"""
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
from itertools import islice
filename = 'DensityByPropagation__a_0_VHxcS_kick'
# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, 192), ylim=(-2, 2))
lineS, = ax.plot([], [], lw=2)
# initialization function: plot the background of each frame
def init():
lineS.set_data([], [])
return lineS,
# animation function. This is called sequentially
def animate(i):
w = np.linspace(0, 2, 1000)
z = np.sin(2 * np.pi * (w - 0.01 * i))
x= np.arange(0,192)
with open(filename) as fobj:
ketchup = islice(fobj, 0, None, 10)
for line in ketchup:
x,y = x,zip(*([float(y) for y in line.split("\t")] for line in fobj))
#plt.plot(x,y)
#plt.show()
#print len(x)
#print len(y)
#lineS.set_data(w,z)
lineS.set_data(x,y)
return lineS,
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init,
frames=200, interval=20, blit=False)
# save the animation as an mp4. This requires ffmpeg or mencoder to be
# installed. The extra_args ensure that the x264 codec is used, so that
# the video can be embedded in html5. You may need to adjust this for
# your system: for more information, see
# http://matplotlib.sourceforge.net/api/animation_api.html
anim.save('movieJoh.mp4', fps=30, extra_args=['-vcodec', 'libx264'])
plt.show()
I'm not sure what exactly is causing your error, but let me point something out, then I'll make a toy example that should help clarify what's happening.
These lines seem unnecessarily complicated.
with open(filename) as fobj:
ketchup = islice(fobj, 0, None, 10)
for line in ketchup:
x,y = x,zip(*([float(y) for y in line.split("\t")] for line in fobj))
If your data is in fact in the simple format you stated, i.e., values separated by spaces, np.loadtxt() would load all the values into an easy to manage array.
Example
Lets assume this is your data file (10 time steps, 2 points on plot at each step):
0 0 0 0 0 0 0 0 0 0
9 8 7 6 5 4 3 2 1 0
Now some code:
filename = 'data.txt'
# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, 1), ylim=(0, 9))
lineS, = ax.plot([], [], lw=2)
x = range(2) # the domain
Now we load the data in with np.loadtxt(), this creates a 2-d matrix with t in the columns and x in the rows. We then transpose it to make indexing each time step possible in animate().
# load the data from file
data = np.loadtxt(filename)
# transpose so we could easily index in the animate() function
data = np.transpose(data)
Now for animation functions. This part is really quite simple. animate(i) takes one argument - the frame number. Using the frame number, we extract the values of f(x,t=frameNumber) and set that as the data on the plot.
# initialization function: plot the background of each frame
def init():
lineS.set_data([], [])
return lineS,
# animation function. This is called sequentially
def animate(i):
lineS.set_data(x, data[i])
return lineS,
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init,
frames=10, interval=100, blit=True)
plt.show()
This is the working code:
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
# Input
filename = 'PeriodicDensity' # Filename
x = np.linspace(-7.5,7.5,192) # Domain
xLimits=[-7.5,7.5] # x limits
yLimits=[0,1] # y limits
framesToUse = range(1,9000,150)# The time-steps to plot
# load the data from file
data = np.loadtxt(filename)
# Set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=xLimits,ylim=yLimits)
lineS, = ax.plot([], [], lw=2)
# Initialisation function
def init():
lineS.set_data([],[])
return lineS,
# Animation function (called sequentially)
def animate(i):
lineS.set_data(x,data[i])
return lineS,
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate, init_func=init,interval=1000, frames=framesToUse, blit=True)
# save the animation as an mp4. This requires ffmpeg or mencoder to be
# installed. The extra_args ensure that the x264 codec is used, so that
# the video can be embedded in html5. You may need to adjust this for
# your system: for more information, see
# http://matplotlib.sourceforge.net/api/animation_api.html
anim.save('movieDensity.mp4', fps=1, extra_args=['-vcodec', 'libx264'])
plt.show()
I have a M x N 2D array: ith row represents that value of N points at time i.
I want to visualize the points [1 row of the array] in the form of a graph where the values get updated after a small interval. Thus the graph shows 1 row at a time, then update the values to next row, so on and so forth.
I want to do this in a jupyter notebook. Looking for reference codes.
I tried following things but no success:
http://community.plot.ly/t/updating-graph-with-new-data-every-100-ms-or-so/812
https://pythonprogramming.net/live-graphs-matplotlib-tutorial/
Create dynamic updated graph with Python
Update Lines in matplotlib
Here's an alternative, possibly simpler solution:
%matplotlib notebook
import numpy as np
import matplotlib.pyplot as plt
m = 100
n = 100
matrix = np.random.normal(0,1,m*n).reshape(m,n)
fig = plt.figure()
ax = fig.add_subplot(111)
plt.ion()
fig.show()
fig.canvas.draw()
for i in range(0,100):
ax.clear()
ax.plot(matrix[i,:])
fig.canvas.draw()
I had been particularly looking for a good answer for the scenario where one thread is pumping data and we want Jupyter notebook to keep updating graph without blocking anything. After looking through about dozen or so related answers, here are some of the findings:
Caution
Do not use below magic if you want a live graph. The graph update does not work if the notebook uses below:
%load_ext autoreload
%autoreload 2
You need below magic in your notebook before you import matplotlib:
%matplotlib notebook
Method 1: Using FuncAnimation
This has a disadvantage that graph update occurs even if your data hasn't been updated yet. Below example shows another thread updating data while Jupyter notebook updating graph through FuncAnimation.
%matplotlib notebook
from matplotlib import pyplot as plt
from matplotlib.animation import FuncAnimation
from random import randrange
from threading import Thread
import time
class LiveGraph:
def __init__(self):
self.x_data, self.y_data = [], []
self.figure = plt.figure()
self.line, = plt.plot(self.x_data, self.y_data)
self.animation = FuncAnimation(self.figure, self.update, interval=1000)
self.th = Thread(target=self.thread_f, daemon=True)
self.th.start()
def update(self, frame):
self.line.set_data(self.x_data, self.y_data)
self.figure.gca().relim()
self.figure.gca().autoscale_view()
return self.line,
def show(self):
plt.show()
def thread_f(self):
x = 0
while True:
self.x_data.append(x)
x += 1
self.y_data.append(randrange(0, 100))
time.sleep(1)
g = LiveGraph()
g.show()
Method 2: Direct Update
The second method is to update the graph as data arrives from another thread. This is risky because matplotlib is not thread safe but it does seem to work as long as there is only one thread doing updates.
%matplotlib notebook
from matplotlib import pyplot as plt
from matplotlib.animation import FuncAnimation
from random import randrange
from threading import Thread
import time
class LiveGraph:
def __init__(self):
self.x_data, self.y_data = [], []
self.figure = plt.figure()
self.line, = plt.plot(self.x_data, self.y_data)
self.th = Thread(target=self.thread_f, daemon=True)
self.th.start()
def update_graph(self):
self.line.set_data(self.x_data, self.y_data)
self.figure.gca().relim()
self.figure.gca().autoscale_view()
def show(self):
plt.show()
def thread_f(self):
x = 0
while True:
self.x_data.append(x)
x += 1
self.y_data.append(randrange(0, 100))
self.update_graph()
time.sleep(1)
from live_graph import LiveGraph
g = LiveGraph()
g.show()
I explored this and produced the following which is largely self-documenting:
import matplotlib.pyplot as plt
%matplotlib notebook
print('This text appears above the figures')
fig1 = plt.figure(num='DORMANT')
print('This text appears betweeen the figures')
fig2 = plt.figure()
print('This text appears below the figures')
fig1.canvas.set_window_title('Canvas active title')
fig1.suptitle('Figure title', fontsize=20)
# Create plots inside the figures
ax1 = fig1.add_subplot(111)
ax1.set_xlabel('x label')
ax2 = fig2.add_subplot(111)
# Loop to update figures
end = 40
for i in range(end):
ax2.cla() # Clear only 2nd figure's axes, figure 1 is ADDITIVE
ax1.set_title('Axes title') # Reset as removed by cla()
ax1.plot(range(i,end), (i,)*(end-i))
ax2.plot(range(i,end), range(i,end), 'rx')
fig1.canvas.draw()
fig2.canvas.draw()
Another simple solution, based on IPython.display functions display and clear_output. I found it here. Here is the code (based on #graham-s's answer):
from IPython.display import display, clear_output
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
m = 100
n = 100
matrix = np.random.normal(0, 1, size=(m, n))
fig = plt.figure()
ax = fig.add_subplot(111)
for i in range(m):
ax.clear()
ax.plot(matrix[i, :])
display(fig)
clear_output(wait=True)
plt.pause(0.2)
It uses %matplotlib inline instead of notebook, and does not produce small image as mentioned by #MasterScrat. Works both in Jupyter Notebook and in Jupyter Lab. Sometimes image blinks that's not very nice, but usable for quick investigations.
If you need to keep axes ranges between different frames, add ax.set_xlim/ax.set_ylim after ax.clear().
With a moderate modification of #Shital Shah's solution, I've created a more general framework which can simply apply to various scenario:
import matplotlib
from matplotlib import pyplot as plt
class LiveLine:
def __init__(self, graph, fmt=''):
# LiveGraph object
self.graph = graph
# instant line
self.line, = self.graph.ax.plot([], [], fmt)
# holder of new lines
self.lines = []
def update(self, x_data, y_data):
# update the instant line
self.line.set_data(x_data, y_data)
self.graph.update_graph()
def addtive_plot(self, x_data, y_data, fmt=''):
# add new line in the same figure
line, = self.graph.ax.plot(x_data, y_data, fmt)
# store line in lines holder
self.lines.append(line)
# update figure
self.graph.update_graph()
# return line index
return self.lines.index(line)
def update_indexed_line(self, index, x_data, y_data):
# use index to update that line
self.lines[index].set_data(x_data, y_data)
self.graph.update_graph()
class LiveGraph:
def __init__(self, backend='nbAgg', figure_arg={}, window_title=None,
suptitle_arg={'t':None}, ax_label={'x':'', 'y':''}, ax_title=None):
# save current backend for later restore
self.origin_backend = matplotlib.get_backend()
# check if current backend meets target backend
if self.origin_backend != backend:
print("original backend:", self.origin_backend)
# matplotlib.use('nbAgg',warn=False, force=True)
plt.switch_backend(backend)
print("switch to backend:", matplotlib.get_backend())
# set figure
self.figure = plt.figure(**figure_arg)
self.figure.canvas.set_window_title(window_title)
self.figure.suptitle(**suptitle_arg)
# set axis
self.ax = self.figure.add_subplot(111)
self.ax.set_xlabel(ax_label['x'])
self.ax.set_ylabel(ax_label['y'])
self.ax.set_title(ax_title)
# holder of lines
self.lines = []
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.close()
def close(self):
# check if current beckend meets original backend, if not, restore it
if matplotlib.get_backend() != self.origin_backend:
# matplotlib.use(self.origin_backend,warn=False, force=True)
plt.switch_backend(self.origin_backend)
print("restore to backend:", matplotlib.get_backend())
def add_line(self, fmt=''):
line = LiveLine(graph=self, fmt=fmt)
self.lines.append(line)
return line
def update_graph(self):
self.figure.gca().relim()
self.figure.gca().autoscale_view()
self.figure.canvas.draw()
With above 2 class, you can simply reproduce #Graham S's example:
import numpy as np
m = 100
n = 100
matrix = np.random.normal(0,1,m*n).reshape(m,n)
with LiveGraph(backend='nbAgg') as h:
line1 = h.add_line()
for i in range(0,100):
line1.update(range(len(matrix[i,:])), matrix[i,:])
Note that, the default backend is nbAgg, you can pass other backend like qt5Agg. When it is finished, it'll restore to your original backend.
and #Tom Hale's example:
with LiveGraph(figure_arg={'num':'DORMANT2'}, window_title='Canvas active title',
suptitle_arg={'t':'Figure title','fontsize':20},
ax_label={'x':'x label', 'y':''}, ax_title='Axes title') as g:
with LiveGraph() as h:
line1 = g.add_line()
line2 = h.add_line('rx')
end = 40
for i in range(end):
line1.addtive_plot(range(i,end), (i,)*(end-i))
line2.update(range(i,end), range(i,end))
Also, you can update particular line in the additive plot of #Tom Hale's example:
import numpy as np
with LiveGraph(figure_arg={'num':'DORMANT3'}, window_title='Canvas active title',
suptitle_arg={'t':'Figure title','fontsize':20},
ax_label={'x':'x label', 'y':''}, ax_title='Axes title') as g:
line1 = g.add_line()
end = 40
for i in range(end):
line_index = line1.addtive_plot(range(i,end), (i,)*(end-i))
for i in range(100):
j = int(20*(1+np.cos(i)))
# update line of index line_index
line1.update_indexed_line(line_index, range(j,end), (line_index,)*(end-j))
Note that, the second for loop is just for updating a particular line with index line_index. you can change that index to other line's index.
In my case, I use it in machine learning training loop to progressively update learning curve.
import numpy as np
import time
# create a LiveGraph object
g = LiveGraph()
# add 2 lines
line1 = g.add_line()
line2 = g.add_line()
# create 2 list to receive training result
list1 = []
list2 = []
# training loop
for i in range(100):
# just training
time.sleep(0.1)
# get training result
list1.append(np.random.normal())
list2.append(np.random.normal())
# update learning curve
line1.update(np.arange(len(list1)), list1)
line2.update(np.arange(len(list2)), list2)
# don't forget to close
g.close()
In addition to #0aslam0 I used code from here. I've just changed animate function to get next row every next time. It draws animated evolution (M steps) of all N points.
from IPython.display import HTML
import numpy as np
from matplotlib import animation
N = 5
M = 100
points_evo_array = np.random.rand(M,N)
# First set up the figure, the axis, and the plot element we want to animate
fig = plt.figure()
ax = plt.axes(xlim=(0, M), ylim=(0, np.max(points_evo_array)))
lines = []
lines = [ax.plot([], [])[0] for _ in range(N)]
def init():
for line in lines:
line.set_data([], [])
return lines
def animate(i):
for j,line in enumerate(lines):
line.set_data(range(i), [points_evo_array[:i,j]])
return lines
# call the animator. blit=True means only re-draw the parts that have changed.
anim = animation.FuncAnimation(fig, animate,np.arange(1, M), init_func=init, interval=10, blit=True)
HTML(anim.to_html5_video())
Hope it will be useful
Here is a library that deals with real-time plotting/logging data (joystick), although I am not sure it is working with jupyter. You can install it using the usual pip install joystick.
Hard to make a working solution without more details on your data. Here is an option:
import joystick as jk
import numpy as np
class test(jk.Joystick):
# initialize the infinite loop decorator
_infinite_loop = jk.deco_infinite_loop()
def _init(self, *args, **kwargs):
"""
Function called at initialization, see the docs
"""
# INIT DATA HERE
self.shape = (10, 4) # M, N
self.data = np.random.random(self.shape)
self.xaxis = range(self.shape[1])
############
# create a graph frame
self.mygraph = self.add_frame(
jk.Graph(name="TheName", size=(500, 500), pos=(50, 50),
fmt="go-", xnpts=self.shape[1], freq_up=5, bgcol="w",
xylim=(0, self.shape[1]-1, None, None)))
#_infinite_loop(wait_time=0.5)
def _generate_fake_data(self): # function looped every 0.5 second
"""
Loop starting with the simulation start, getting data and
pushing it to the graph every 0.5 seconds
"""
# NEW (RANDOM) DATA
new_data = np.random.random(self.shape[1])
# concatenate data
self.data = np.vstack((self.data, new_data))
# push new data to the graph
self.mygraph.set_xydata(self.xaxis, self.data[-1])
t = test()
t.start()
t.stop()
t.exit()
This code will create a graph that is auto-updating 5 times a second (freq_up=5), while new data is (randomly) generated every 0.5 seconds (wait_time=0.5) and pushed to the graph for display.
If you don't want the Y-axis to wiggle around, type t.mygraph.xylim = (0, t.shape[1]-1, 0, 1).
I don't know much about matplotlib or jupyter. However, Graphs interest me. I just did some googling and came across this post. Seems like you have to render the graph as an HTML video to see a dynamic graph.
I tried that post. This is the notebook, if you wish to try. Note that the kernel (python 2) takes sometime to build the video. You can read more about it here.
Now you want to display a graph row to row. I tried this. In that notebook, I have a dump_data with 10 rows. I randomly take one and plot them and display as video.
It was interesting to learn about jupyter. Hope this helps.
Why are my datapoints being displayed like this when new data is being dumped via stream into "twitter-out"? Seems like it has to do with the animation, because when I rerun the file without streaming in new data it plots just fine.
style.use('ggplot')
fig = plt.figure()
ax1 = fig.add_subplot(1, 1, 1)
def animate(self):
pullData = open("twitter-out.txt", "r").read()
lines = pullData.split('\n')
xar = []
yar = []
x = 0
y = 0
for l in lines[:]:
x += 1
if "['pos']" in l:
y += 1
elif "['neg']" in l:
y -= 1
xar.append(x)
yar.append(y)
ax1.plot(xar, yar,color='r')
ax1.set_xlabel('Number of Tweets')
ax1.set_ylabel('Sentiment')
ani = animation.FuncAnimation(fig, animate, interval=1000)
plt.show()
Fix 1:
The main fix for this is very easy : just add ax1.cla() before you call ax1.plot()
Explanation :
The reason for what you see is that the animation draws a new plot each time the animate function is called and stack it above all the previous ones.
So the figure you have attached in your question is actualy a superposition of the dozen figures that were drawn from the animate calls.
To solve that you just have to clear the previous plots that were contained in your axes with the clear axes command ax.cla().
Fix 2:
The reason for the horizontal bars to be there at all is because your dataPulled string always ends with a new line that turns in an empty string at the end of your list line.
See that example:
>>> 'a\nb\n'.split('\n')
['a', 'b', '']
So you have to cut that last one out in your for loop:
for l in lines[:-1]:
I'm trying to monitor real-time data with matplotlib.
I found that I can update plot dynamically with interactive mode in Pyplot.
And it worked well, but one problem is 'I cannot manipulate the figure window at all'. For example, move or re-size the figure window.
Here is my code.
This is cons of interactive mode? or I'm using it incorrectly?
import matplotlib.pyplot as plt
import time
import math
# generate data
x = [0.1*_a for _a in range(1000)]
y = map(lambda x : math.sin(x), x)
# interactive mode
plt.ion() # identical plt.interactive(True)
fig, ax = plt.subplots()
# ax = plt.gca()
lines, = ax.plot([], [])
# ax.set_ylim(-1, 1)
ax.grid()
MAX_N_DATA = 100
x_data = []
y_data = []
for i in range(len(x)):
# New data received
x_data.append(x[i])
y_data.append(y[i])
# limit data length
if x_data.__len__() > MAX_N_DATA:
x_data.pop(0)
y_data.pop(0)
# Set Data
lines.set_xdata(x_data)
lines.set_ydata(y_data)
# The data limits are not updated automatically.
ax.relim()
# with tight True, graph flows smoothly.
ax.autoscale_view(tight=True, scalex=True, scaley=True)
# draw
plt.draw()
time.sleep(0.01)
Thank you.
As shown in this answer to another question, replace plt.draw() with plt.pause(0.05). This solved the problem for me.
Although I still think you should use bokeh, I'll tell you how to do it with matplotlib.
The problem why it won't work ist that matplotlib's event loop is not active and therefore it cannot digest window events (like close or resize). Unfortunately it is not possible to trigger this digestion from the outside. What you have to do is to use matplotlib's animation system.
Your code is actually quite well prepared for it so you can use FuncAnimation.
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation
import math
# generate data
x = [0.1*_a for _a in range(1000)]
y = map(lambda x : math.sin(x), x)
# don't need ion, we're using block=True (see end of code)
fig, ax = plt.subplots()
fig.show()
# ax = plt.gca()
lines, = ax.plot([], [])
# ax.set_ylim(-1, 1)
ax.grid()
MAX_N_DATA = 100
x_data = []
y_data = []
def showdata(i):
# New data received
x_data.append(x[i])
y_data.append(y[i])
# limit data length
if x_data.__len__() > MAX_N_DATA:
x_data.pop(0)
y_data.pop(0)
# Set Data
lines.set_xdata(x_data)
lines.set_ydata(y_data)
# The data limits are not updated automatically.
ax.relim()
# with tight True, graph flows smoothly.
ax.autoscale_view(tight=True, scalex=True, scaley=True)
# draw will be called by the animation system
# instead of time.sleep(0.01) we use an update interval of 10ms
# which has the same effect
anim = FuncAnimation(fig, showdata, range(len(x)), interval=10, repeat=False)
# start eventloop
plt.show(block=True)