Create a circle function

I am interested in creating an actual path where I calculate a given function for a particle that travels along a given path. I am new to MATLAB, and I am having trouble creating a circular path. I can graph a circle (there are many MATLAB tutorials that show how to do this), but I would need to call such a path by one variable name, say rpath. Thus when I am prompted to enter the path the particle will take, I can enter rpath, and the particle will take a circular path starting from (1,0) and ending at (1,0) in the complex plane (I have the complex plane already programmed, I am just looking for the path. This seems a little bit more complicated than all the other circle questions I can find. My trouble is trying to create such a path in MATLAB.

For a straight line starting and ending at a specific point, I did the following, which works:

x = [0.4:0.01:1.5];
y = (-1.55/1.1).*x + (1.55*1.5/1.1);

complex = x+iy
Complex = fliplr(complex)

B_01n = Complex

Thus B_01n here is my path, and I enter this when I am asked for a path. I want to do the same for a circular path with the given conditions above. Any suggestions?

Answer 1

[Star Strider]

This works:

rpath = exp(linspace(0, 2*pi)*1i);

figure(1)
plot(real(rpath), imag(rpath))
grid
axis equal
axis([-2  2   -2  2])

[BM]

Can't believe I didn't think of the exponential function! Works well, but not perfect yet.

The path should start at (1,0) and end at (1,0). I should add that I would like the path to have its lowest point at (1,0) as well. Would linspace allow me to set a certain amount of steps in my path if I wanted say 50 steps, or 100 steps?

[Star Strider]

Thank you.

This is the best I can do:

rpath = exp((linspace(0, 2*pi)-pi/2)*1i)+[1+1i];

figure(1)
plot(real(rpath), imag(rpath))
grid
axis equal
axis([-0.5  2.5   -0.5  2.5])
text(real(rpath(1)), imag(rpath(1)), sprintf('\\uparrow\n[%.1f+%.1fj]\nStart',real(rpath(1)),imag(rpath(1))), 'VerticalAlignment','top')

The third argument to linspace are the number of points you want it to calculate. The default is 100, and you can generate as many points as your computer has the memory to accommodate. I find that 100 plots a decent circle, however this depends on the size and resolution of your monitor, unless you need more or fewer points for some other reason.

[BM]

Yes, modified the code, starting from what you gave me. It works beautifully. Thanks again.

[Star Strider]

My pleasure.