How to evaluate an algebraic expression at a certain point when it is in a matrix?

In the below expressions:

syms x1 x2 H f
xs = [1 1];
f = (12*x1^3 - 20*x1^3*x2^2 + 6*x2^2 + x1^2 +9);
H = hessian(f);

So the term H(1,1) would be a symbolic with a value (- 120*x1*x2^2 + 72*x1 + 2)

What is the simplest way to calculate the value of this expression at a point, say (x1,x2) = (1,2) ?

Answer 1

[ANKUR KUMAR]

You can use matlabFunction to create an anonymous function, which will eventually help to calcuate the values at specific x1 and x2.

syms x1 x2 H f
xs = [1 1];
f1 = (12*x1^3 - 20*x1^3*x2^2 + 6*x2^2 + x1^2 +9);
func=matlabFunction(hessian(f1));
func(1,2)

[Aravind Vissamsetty]

Thank you!