Function File: W = gram (sys, mode)

Function File: Wc = gram (a, b)

gram (sys, "c") returns the controllability gramian of the (continuous- or discrete-time) system sys. gram (sys, "o") returns the observability gramian of the (continuous- or discrete-time) system sys. gram (a, b) returns the controllability gramian Wc of the continuous-time system \(\dot{x} = A x + B u\) i.e., Wc satisfies \(A\, Wc + m Wc^T + B\,B^T = 0\)