Computing the inverse of function in MATLAB

Question

How do you compute the inverse of a function in MATLAB? Say you want to compute the inverse of f(x)=e^x, what would be the code?

Answer 1

If the analytical approach fails (which is preferred whenever possible) use numerical approach:

Given y and guess x0 for the inverse

x = fzero( @(x)(f(x)-y), x0 ); 

or a low accuracy but faster method when the range of x known to be bounded in xmin...xmax

xx = linspace( xmin, xmax, N );
yy = f(xx);
x = interp1(yy, xx, y);

Of course, N has to be chosen according to the desired accuracy.