Matplotlib hangs when plotting

Question

I am trying to plot some datetime objects in Python with Matplotlib, just as I have seen at this question.

But when it gets to the savefig call, it gets stuck. This is my code:

import matplotlib as mpl
mpl.use('Agg')  # Matplotlib backend to use without an X-server
import matplotlib.pyplot as plt
from matplotlib.dates import DateFormatter, MinuteLocator
from datetime import datetime
from datetime import timedelta

def plot_scenario(outages_start, outages_end, prediction_start, prediction_end,
    filepath=None):

    fig = plt.figure()
    ax = fig.add_subplot(111)

    y = [0.3, 0.7]
    timelines(ax, y[0], prediction_start, prediction_end, color='r')
    for xstart, xstop in zip(outages_start, outages_end):
        timelines(ax, y[1], xstart, xstop)

    ax.xaxis_date()
    myFmt = DateFormatter('%d %H:%M')
    ax.xaxis.set_major_formatter(myFmt)
    ax.xaxis.set_major_locator(MinuteLocator(0, interval=15))

    # Delta needed to adjust the xlimits
    delta = (prediction_end - prediction_start) / 10

    #ax.set_yticks(['Prediction', 'Outages'])  #Not working
    ax.set_ylim(0, 1)
    ax.set_xlim(prediction_start - delta, prediction_end + delta)
    ax.set_xlabel('Time')

    if filepath is None:
        fig.show()
    else:
        # Save plot as PNG
        fig.savefig(filepath) # Gets stuck here
        print 'PGN file saved at ' + filepath


# plot timelines at y from xstart to xstop with a given color
def timelines(current_axis, y, xstart, xstop, color='b'):
    current_axis.hlines(y, xstart, xstop, color, lw=4)
    current_axis.vlines(xstart, y+0.03, y-0.03, color, lw=2)
    current_axis.vlines(xstop, y+0.03, y-0.03, color, lw=2)

if __name__ == '__main__':
    prediction_start = datetime(2014, 3, 20) + timedelta(hours=12)
    prediction_end = prediction start + timedelta(hours=10)
    outages_start = []
    outages_end = []
    outages_start.append(datetime(2014, 3, 20) + timedelta(hours=14))
    outages_end.append(datetime(2014, 3, 20) + timedelta(hours=15))
    outages_start.append(datetime(2014, 3, 20) + timedelta(hours=17))
    outages_end.append(datetime(2014, 3, 20) + timedelta(hours=18))

    path = '/home/myuser/test.png'
    plot_scenario(outages_start, outages_end, prediction_start, prediction_end, path)

I'm using Agg since I'm working without X-server into an Ubuntu Server machine, but this can't be the problem because I made a simple range plot and the figure was saved correctly, so I must be making some mistake at the code.

Any help?

Can you try to reduce the amount of code here? Without the ability to reproduce your problem there isn't much anyone can do to help you. — tacaswell
– tacaswell, Commented Mar 20, 2014 at 16:42
It is currently a small code, just the main is missing, so I don't know what the problem is, or why I'm deserving a downvote. I'll add the main anyway — Roman Rdgz
– Roman Rdgz, Commented Mar 20, 2014 at 16:55
The problem isn't length, it is that it is not runnable. sscce.org — tacaswell
– tacaswell, Commented Mar 20, 2014 at 16:57
And you got a down vote because you have enough rep to know better. — tacaswell
– tacaswell, Commented Mar 20, 2014 at 16:58

Roman Rdgz · Accepted Answer · 2014-03-25 08:05:11Z

1

Looks like the problem is in the line:

ax.xaxis.set_major_locator(MinuteLocator(0, interval=15))

But I don't really know why. Commenting that line, the code works.

answered Mar 25, 2014 at 8:05

Roman Rdgz

13.4k42 gold badges140 silver badges212 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Matplotlib hangs when plotting

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related