How to define a column vector whose elements are column vector?

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Deepak Patankar
Deepak Patankar 2017-7-4
评论： Guillaume 2017-7-4
I want to define a matrix like d=[ [1;2;3] ; [4;5;6] ; [7;8;9] ] such that d(1) gives a 3X1 matrix [1;2;3], but instead I am getting d matrix as 9X1 as d(1)=1. How can I represent my d matrix in the form given above?

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回答（2 个）

Guillaume
Guillaume 2017-7-4
You have to use a cell array:
d = {[1;2;3]; [4;5;6]; [7;8;9]};
d{1} %to get the first vector
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Deepak Patankar
Deepak Patankar 2017-7-4
Thanks Sir
Actually I am using ssest(data(as iddata),nx) to find the estimated parameters for my state space model.
x[t+Ts]=Ax[t] + Bu[t]
y[t] = C*x[t]
where u[t] is a nX3 matrix( n is number of sample) and y[t] is n*1 matrix.
Since u[t] is nX3 the output y[t] comes 1X3, but to get the best estimate y[t] must be 1X1 ( I tried taking y as [output,0,0] and few more combinations it was not giving good result). Thus to take y as 1X1 my u must be 3X1, that's why I asked the question which you answered earlier.But I am unable to use cell array in iddata. Can you suggest some solution for the actual problem ?
Guillaume
Guillaume 2017-7-4
I know nothing about state space model and I don't really understand your problem.
In any case, since it's so vastly different to the question you've asked here, start a new question. You'll be a lot more likely to get an answer. Be a lot clearer in your new question.

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David Goodmanson
David Goodmanson 2017-7-4
Hello Deepak,
If you want to create an actual matrix that you could access with a slightly different syntax, then
% commas concatenate horizontally, semicolons concatenate vertically
d=[ [1;2;3] , [4;5;6] , [7;8;9] ]
and then the columns would be addressed as d(:,1) = [1;2;3] etc.
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Deepak Patankar
Deepak Patankar 2017-7-4
编辑：Deepak Patankar 2017-7-4
Thanks a lot sir for your answer
The question I asked was a small part of my actual problem which I have mentioned in Guillaume Sir's answer. Can you help me with the actual problem,I am trying it from quite a few days ?

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