How to plot six concentric circles using meshgrid and plot?

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Yuval 2013-3-27

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I am trying to plot six concentric circles using meshgrid() and plot(). The circles' radii vary between 0.5 and 1.75 (with intervals of 0.25). I am wondering whether the code below is sufficiently efficient and whether indeed it should be performed as delineated below:

theta = linspace(0, 2*pi, 50);
[X, Y] = meshgrid(0.5:0.25:1.75, theta);
plot(a+cos(Y).*X, b+sin(Y).*X);

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Image Analyst 2013-3-27

Yeah - it does, but so? What is the question?

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Matt J 2013-3-27

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You could conserve a little memory if you did it this way, but I don't know anyone who cares about efficiency for such a small plotting task,

theta = linspace(0, 2*pi, 50).';
R=0.5:0.25:1.75;
plot(a+cos(theta)*R, b+sin(theta)*R);

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Yuval 2013-3-27

编辑：Yuval 2013-3-27

I mean I ran mine, the original one I posted here, in which the transpose was clearly omitted, and yet the plot was just as that generated by your own code, with the transpose. Is that still impossible? Did you mean to suggest that that is strictly mandatory if R is defined as you proposed? Please allow me to re-post what works perfectly fine on this machine:

theta = linspace(0, 2*pi, 50); R = 0.5: 0.25: 1.75; [X, Y] = meshgrid(R, theta); plot(a+cos(Y).*X, b+sin(Y).*X);

Matt J 2013-3-27

编辑：Matt J 2013-3-27

Yes, the transposition of theta was only relevant to my proposed approach -- the one that does not use meshgrid. Notice that you use elementwise .* multiplication whereas I use pure matrix multiplication '*'. Matrix multiplication requires the operands to be appropriately shaped.

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