hessian calculates the Hessian \(d^2^f/dx^2\) of a polynomial expression
H = hessian(f,x)
With only 1 argument, the differentiation is performed with respect to all involved variables
x1 = sdpvar(1,1); x2 = sdpvar(1,1); f = x1^4+5*x2^2; sdisplay(hessian(f)) ans = '12*x1^2' '0' '0' '10'
Giving a second argument controls what variables to differentiate with respect to
sdisplay(hessian(f,x1)) ans = '12x1^2'