How do I create a 2D sparse matrix?

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Marwa Helemish
Marwa Helemish 2011-2-8
Hallo, When I want to creat a sparse matrix, and and according to the i verctor( index) the element must be equal =1
say i=[6 12 18 24 19 13 7 1]; A=sparse(i,i,ones(1,8)); then I have A =
(1,1) 1
(6,6) 1
(7,7) 1
(12,12) 1
(13,13) 1
(18,18) 1
(19,19) 1
(24,24) 1
Now:I want to creat a A 2D sparse matrix with vector i, but with every element are a 2D matrix 3x3 for exmaple A(1,1) is 2D matrix of dimension 3x3=[1 0 0;0 1 0; 0 0 1]; thank you in advance
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Bruno Luong
Bruno Luong 2011-2-10
A (sparse) matrix can contain numerical elements and nothing else. What exactly you want to do?

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采纳的回答

Marwa Helemish
Marwa Helemish 2011-2-10
sorry Andrew,i canot accept it because , it is not want I mean. Many thanks again
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Andrew Newell
Andrew Newell 2011-2-10
Then what do you mean? I suggest editing your original question to clarify it.

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更多回答（2 个）

Andrew Newell
Andrew Newell 2011-2-8
Here is how you would do it for your example:
N = 6; % I assume this is a square matrix?
A = zeros(3,3,N^2);
A3 = eye(3);
indexList = [6 12 18 24 19 13 7 1];
for i=indexList
A(:,:,i) = A3;
end
A = num2cell(A,[1 2]);
A = reshape(A,N,N);
A = sparse(cell2mat(A));
EDIT: If you're really after a sparse cell array of matrices, try looking at Sparse cell arrays.
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Todd Flanagan
Todd Flanagan 2011-2-8
Andrew says, "If you like this answer, could you please accept it?"

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James Tursa
James Tursa 2011-3-21
You might take a look at this FEX submission by Matt J:
http://www.mathworks.com/matlabcentral/fileexchange/29832-n-dimensional-sparse-arrays

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