Riccati equation
X=riccati(A,B,C,dom,[typ]) [X1,X2]=riccati(A,B,C,dom,[typ])
real matrices nxn, B and C symmetric.
'c' or 'd' for the time domain (continuous or discrete)
string : 'eigen' for block diagonalization or schur' for Schur method.
square real matrices (X2 invertible), X symmetric
X=riccati(A,B,C,dom,[typ]) solves the Riccati equation:
in continuous time case, or:
with B=B1/B2*B1' in the discrete time case.
If called with two output arguments, riccati returns X1,X2
such that X=X1/X2.