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From: Philipp on 25 Sep 2005 18:41
Hi
I am using idgrey.m in the system identification toolbox
to estimate a discrete time state space model

X(parvec,t+1) = A(parvec) X(parvec,t) + K(parvec) e(t)
Y(t)= C(parvec) X(parvec,t) + e(t)

I wrote the function 'Estimation' to parameterize (A(parvec),
C(parvec), and K(parvec))

defined the object m
m=idgrey('Estimation',par,'d',aux,1/12);

and then started the estimation

me=pem(Data,m,'Filearg',aux,
'Trace','Full','LimitError',0,'Tolerance',1e-15,'Ts',1/12,'MaxIter',50
0);

the estimation works but for some parameter values I sometimes get
this error message

INITIAL ESTIMATE
Current loss: 1.8817e-037
par-vector:
0.5760
3.3430
0
0.0830

??? Error using ==> subsref
Reference to non-existent field 'K'.

Error in ==> <a
href="error:c:\matlab701\toolbox\ident\ident\@idmodel\pvget.m,24,1"&gt
;idmodel.pvget at 24</a>
Value =
builtin('subsref',sys.EstimationInfo,ssubs);

Any help in dealing with this error message is appreciated

Thanks
Philipp
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