Plotting time-course of matrix entries
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Paul Fishback on 15 Oct 2013
I have a matrix with real-valued, nonnegative entries. For entry (i,j), I wish to plot a filled circle at the point (i,j) whose color intensity is determined by the magnitude of M(i,j). So for example, if M(2,3) > M(4,8), then a darker dot would appear at (2,3) than at (4,8). I want to draw filled circles as opposed to colored rectangles as one would do using pcolor
EXTRA CREDIT: If the entries of M also change with time, i.e. each entry takes the form M(i,j,t), how could I go about creating an animation that shows the time-course of the various magnitudes. For example, if M(2,3,t) is an increasing function of t, I would want the color intensity of the filled dot at (2,3) to increase.
Jonathan LeSage on 16 Oct 2013
Edited: Jonathan LeSage on 16 Oct 2013
Extra credit time! Depending on how you want to ultimately display your results, you have quite a few options. For a quick and dirty approach to plotting your data over time, you can just sequentially update a plot using the imagesc function to depict color intensity of your matrix.
Here is some quick code which illustrates that method:
% Generate a 2x2x10 matrix (x,y,t)
N = 10;
x = reshape(1:N,1,1,10);
dataMat = [rand(1,1,N), 20-x;
colorLimits = [min(dataMat(:)) max(dataMat(:))];
% Step through and plot along the t-axis
for i = 1:N,
pause(0.5); % Half a second pause between frames
To actually animate these results, you can refer to the discussion from another answers question from yesterday:
Finally, as another possibility for displaying your data, you should check out the sliceomatic function that is available on the File Exchange:
Hope this helps to get you started!