Liren Large Software Subsidy 10/10.iso/l/l455/9.ddi/IDENT.DI$/MODSTRUC.M

Text File | 1993-03-11 | 1.9 KB | 55 lines

function mod=modstruc(a,b,c,d,k,x0)
%MODSTRUC  Constructs model structures to be used in MS2TH
%
%    MS = modstruc(A,B,C,D,K,X0)
%
%    MS = The resulting model structure.
%    A,B,C,D,K,X0 are the matrices of the state space model
%
%    xnew = A x(t) + B u(t) + K e(t)
%    y(t) = C x(t) + D u(t) + e(t)
%
%    where xnew is x(t+T) or dx(t)/dt. X0 is the initial state.
%
%    The entries of these matrices are numerical values for the parameters
%    that are fixed, while a parameter to be    estimated (a free parameter) is
%    entered as NaN in the corresponding position.
%    Example: A=[0 1;NaN NaN].
%    The default value of X0 is zeros.
%    See also CANFORM

%    L. Ljung 10-2-90,5-5-92
%    Copyright (c) 1990 by the MathWorks, Inc.
%    All Rights Reserved.

if nargin<5,error('All of the matrices A, B, C, D, K, must be specified!'),end
[nx,nd]=size(a);
if nx ~= nd, error('The A-matrix must be square!'),end
if nargin<6, x0=zeros(nx,1);end,if isempty(x0),x0=zeros(nx,1);end
[nd,nu]=size(b);
if nx ~= nd & nu~=0, error('A and B must have the same number of rows!'),
end
[ny,nd]=size(c);
if nx ~= nd, error('A and C must have the same number of columns!'),
end
[nd1,nd2]=size(d);
if nd1 ~= ny & nu~=0, error('D and C must have the same number of rows!'),end
if nd2 ~= nu, error('D and B must have the same number of columns!'),
end
[nd1,nd2]=size(k);
if nd1 ~= nx, error('K and A must have the same numb er of rows!'),
end
if nd2 ~= ny, error('The number of columns in K must equal the number of coulumns in C!'),end
[nd1,nd2]=size(x0);
if nd1~=nx, error('X0 and A must have the same number of rows!'),end
if nd2 ~= 1, error('X0 must be a coulmn vector!'),end
mod(1:nx,1:nx)=a;
if nu>0, mod(1:nx,nx+1:nx+nu)=b;end
mod(1:nx,nx+nu+1:nx+nu+ny)=c';
if nu>0, mod(1:ny,nx+nu+ny+1:nx+2*nu+ny)=d;end
nn=nx+2*(nu+ny);
mod(1:nx,nx+2*nu+ny+1:nn)=k;
mod(1:nx,nn+1:nn+1)=x0;
mod(1,nn+2)=ny;mod(2,nn+2)=nx;