MATLAB: Plot a function in 3D

3dfuntionplot

I have variables a and b both defined in [-1,+1] and the function c = a / (a + b)

How can I plot c in 3D to visualize the function?

RESOLUTION=20;   %increase this for a finer grid
t = linspace(-1,1,RESOLUTION);
[a,b] = ndgrid(t,t);
c = a./(a+b);
surf(a,b,c);

It is, however, not possible to plot it as a continuous surface, as your graphics display only has discretized output locations ("pixels").

voronoi([a(:,1), b(:,1), c(:,1)], [a(:,2),b(:,2),c(:,2)])

I haven't tried this entirely, but instead of cla and replotting try

figure(1)

contourf(1,b,c)'

h = colorbar('YScale','log');

d = log10(c);

figure(2)

contourf(a,b,d)

a = get(1,'children');

copyobj(a(1),2);

This is a crude reparenting of the colorbar from the original figure to the new one.