[Matplotlib-users] Labels in a dynamic graph

[Amit F. <ami...@gm...>]

Hi everyone,


I am using matplotlib to dynamically plot a graph with both my x and y
points taken from a measurement device. That is to say, in each
iteration of my while loop I'm reading two variables which I then want
to plot with matplotlib.


I wrote something which goes like this (disregard the Gnuplot - that's
what I'm trying to replace with matplotlib...)



    import gpib, Numeric, time, Gnuplot, mymodule, threading
    from pylab import *

   

    def cooldown(filename, dmm_gpib, lake_gpib):

    """this program scans dummy and reads HP and Lakeshore"""

    A             = Numeric.arange(-1, 1, .1)
    delay         = 1
    f = open(filename,'w')


    X = []
    Y = []
    figure(2)
    hold(False)
        try:       
            while A[0]<10:

                gpib.write(lake_fd, 'SDAT?')
                gpib.write(hp_fd, 'read?')
                time.sleep(delay)
                val1 = float(gpib.read(lake_fd, 30))
                val2 = float(gpib.read(hp_fd, 30))
                X.append(val1)
                Y.append(val2)
                plot(X,Y,'.-')
                f.write(str(val1) + '\t' + str(val2) + '\n')
                f.flush()

I'm running this code in ipython with the -pylab option, so I don't need
to use show(). My question is, how do I maintain a *constant* xlabel and
ylabel without having to redraw them each time I append a point to the
graph? If I try xlabel('something') then obviously it's cleared each
time I use plot(X,Y).

Any ideas?

Thanks,

Amit.