how can i write this matrix in matlab?

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mohammad azsad
mohammad azsad 2014-11-2
评论： dpb 2014-11-3
how can i write this matrix in matlab? this matrix is (n+1)*(n+1) that n must be enter by user

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采纳的回答

Rick Rosson
Rick Rosson 2014-11-2
x = zeros(n+1);
x(1,1:2) = [ 2 1 ];
x(end,end-1:end) = [ 1 2 ];
for k = 2:n
x(k,k–1:k+1) = [ 1 4 1 ];
end

更多回答（2 个）

dpb
dpb 2014-11-2
Given input n and
r = [1 4 1];
c={repmat(r,n,1)}; % cell array of n copies of r
m=blkdiag([2 1],c{:},[1 2]); % expand c to comma list for blkdiag
clear c
Image Analyst
Image Analyst 2014-11-2
Lots of ways, for loop, addition, assignment, zeros(), etc. I'd probably use eye() and circshift(). Hint:
diagArray = 4 * eye(7)
See what that gives you. Imagine shifting some diagonal arrays with circhsift() and adding the 3 arrays together. That should be enough hint to get you started.
  1 个评论
dpb
dpb 2014-11-3
I thought the blkdiag solution kinda' cute, IA... :)
Excepting for needing the temporary cell array; couldn't see a simple way to generate the comma-separated list in one swell foop...

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