inistate Estimates the initial state of a discrete-time system Calling Sequence X0 = inistate(SYS,Y,U,TOL,PRINTW) X0 = inistate(A,B,C,Y,U); X0 = inistate(A,C,Y); [x0,V,rcnd] = inistate(SYS,Y,U,TOL,PRINTW) Arguments SYS given system, syslin(dt,A,B,C,D) Y the output of the system U the input of the system TOL TOL is the tolerance used for estimating the rank of matrices. If TOL > 0, then the given value of TOL is used as a lower bound for the reciprocal condition number. Default: prod(size(matrix))*epsilon_machine where epsilon_machine is the relative machine precision. PRINTW PRINTW is a switch for printing the warning messages. = 1: print warning messages; = 0: do not print warning messages. Default: PRINTW = 0. X0 the estimated initial state vector V orthogonal matrix which reduces the system state matrix A to a real Schur form rcnd estimate of the reciprocal condition number of the coefficient matrix of the least squares problem solved. Description inistate Estimates the initial state of a discrete-time system, given the (estimated) system matrices, and a set of input/output data. X0 = inistate(SYS,Y,U,TOL,PRINTW) estimates the initial state X0 of the discrete-time system SYS = (A,B,C,D), using the output data Y and the input data U. The model structure is : = 1, y(k) = Cx(k) + Du(k), ]]> The vectors y(k) and u(k) are transposes of the k-th rows of Y and U, respectively. Instead of the first input parameter SYS (an syslin object), equivalent information may be specified using matrix parameters, for instance, X0 = inistate(A,B,C,Y,U); or X0 = inistate(A,C,Y); [x0,V,rcnd] = inistate(SYS,Y,U,TOL,PRINTW) returns, besides x0, the orthogonal matrix V which reduces the system state matrix A to a real Schur form, as well as an estimate of the reciprocal condition number of the coefficient matrix of the least squares problem solved. Examples See Also findBD findx0BD