The new Matplotlib book shows how to animate line drawing. What I really needed was bar graphs. I didn’t see an example of animating bar graphs in the book (probably because it is follows naturally from the line animation example). The bar graph documentation for matplotib shows how to create a set of bar graphs. The code for animated bars is below.

import sys
from PyQt4 import QtGui

from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas

import numpy as np

class Monitor(FigureCanvas):
def __init__(self):
self.fig = Figure()

FigureCanvas.__init__(self, self.fig)

# the file is 5 float values separated by spaces on every line, like this:
#0.28 0.18 0.18 0.18 0.18
#0.352 0.162 0.162 0.162 0.162
#0.4168 0.1458 0.1458 0.1458 0.1458
#0.37512 0.23122 0.13122 0.13122 0.13122
self.data = [np.array(map(float, line.strip().split())) for line in open('data.txt').readlines()]
self.counter = 1

# the width of the bars
self.width = 0.8

# the locations of the bars
self.locs = np.arange(len(self.data[0]))

# the first set of bars
self.bars = self.ax.bar(self.locs, self.data[0], self.width, color='#6a7ea6')

# set up the lables for the bars
self.ax.set_xticks(self.locs+0.5)
self.ax.set_xticklabels(['Red', 'Green', 'Black', 'Orange', 'Yellow'])

# set the limit for the x and y
self.ax.set_xlim(0., len(self.data[0]))
self.ax.set_ylim(0., 1.,)

# draw the canvas
self.fig.canvas.draw()

# start the timer
self.timer = self.startTimer(1000)

def timerEvent(self, evt):
# update the height of the bars, one liner is easier
[bar.set_height(self.data[self.counter][i]) for i,bar in enumerate(self.bars)]

# force the redraw of the canvas
self.fig.canvas.draw()

# update the data row counter
self.counter += 1

if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
w = Monitor()
w.setWindowTitle("Convergence")
w.show()
sys.exit(app.exec_())