MATLAB: Do the axis change dimensioins

contourmultivariatesurf plotsurface plot

Hi All, this code is supposed to plot a 3D surface and a contour plot of the function with wells at (-2, 2) and (3, -1). However, when I run the code, firstly, the wells are not in the right places, and the dimensions of the axis change as my inputs for x and y change (ie the position of the wells change). What am I doing wrong?
Here is my code, 
function M = landscape(x, y)
 
M = H1(x, y) + H2(x, y); 
  
    function h1 = H1(x, y)
        R1 = 2;
        s1 = [-2;2];
        n1 = 2;
        
       h1 = (1./(1+(R1./sqrt((x-s1(1)).^2+(y(:)-s1(2)).^2)).^n1));
    end
 
    function h2 = H2(x, y)
        R2 = 1;
        s2 = [3;-1];
        n2 = 1;
        
       h2 = (1./(1+(R2./sqrt((x-s2(1)).^2+(y(:)-s2(2)).^2)).^n2));
    end
subplot(1, 2, 1)
surf(M)
subplot(1, 2, 2)
contour(M)
end
And two different graphs the first with x and y -5:5 and the second with x and y -10:10
landscape55.jpg
landscape1010.jpg
Notice how the position of the wells change?

Best Answer

What happens, according to the documentation, when you call surf with one input argument? What does surf use for the X and Y coordinates at which to place the points that make up the surface?
Try calling surf with three input arguments instead.
The same applies to the contour function. You called it with one input when you should be calling it with three.
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