Scilab Function
Last update : 18/05/2014

lyap - Lyapunov equation

Calling Sequence

[X]=lyap(A,C,'c')
[X]=lyap(A,C,'d')

Parameters

Description

X = lyap(A,C,flag) solves the continuous time or discrete time matrix Lyapunov matrix equation:


       A'*X + X*A = C       ( flag='c' )
      A'*X*A - X = C       ( flag='d' )
   
    

Note that a unique solution exist if and only if an eigenvalue of A is not an eigenvalue of -A (flag='c') or 1 over an eigenvalue of A (flag='d').

Examples


A=rand(4,4);C=rand(A);C=C+C';
X=lyap(A,C,'c');
A'*X + X*A -C
X=lyap(A,C,'d');
A'*X*A - X -C
 
  

See Also

sylv,  ctr_gram,  obs_gram,