Sparse 3D matrix

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TR RAO 2018-7-11

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评论： TR RAO 2018-7-11

Suppose I have a sparse matrix F of order 4 x 4. Now I want to store this sparse matrix in 3d matrix. What is the syntax for this representation. that is I want to assign A(:, :,1) = F. Since F is sparse it is showing an error. But if I assign A(:, :,1) = full(F), then it is working. But in that case F is not sparse. F consists of many zeros. Kindly tell me how to assign a sparse matrix in a 3d matrix.

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Guillaume 2018-7-11

@TR RAO, You've already asked this question a day earlier. No matter how many times you asked, the answer will be the same.

TR RAO 2018-7-11

Sir, Thank You Sir. Yesterday I could not understand after reading sparse matrices. Now I understood.

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Answer 1

Matt J 2018-7-11

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编辑：Matt J 2018-7-11

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You can't hold a normal Matlab 3D array in sparse form, but you can do it with my ndSparse class (Download), as long as you're mindful of the limitations.

    Afull=cat(3,eye(4),diag([14,0,0,27]));   %example
      Afull(2,3,2)=52;
    F=sparse(diag([20,0,40,50]));  %example
    >> A=ndSparse(Afull); A(:,:,1)=F,
      A(:,:,1) =
         (1,1)       20
         (3,3)       40
         (4,4)       50
      A(:,:,2) =
         (1,1)       14
         (2,3)       52
         (4,4)       27
    >> whos A Afull
    Name       Size             Bytes  Class       Attributes
    A          4x4x2              160  ndSparse              
    Afull      4x4x2              256  double