create a sparse matrix. in matlab

One approach to create and manage sparse matrices in Matlab is to use the sparse function. The sparse function allows you to create a sparse matrix with specific values at specific positions. Here's an example of creating a sparse matrix A with values 1, 2, and 3 at (1,2), (2,3), and (3,1) respectively:

main.m
% Create a 3x3 sparse matrix
A = sparse(3, 3);

% Assign values to specific positions
A(1,2) = 1;
A(2,3) = 2;
A(3,1) = 3;
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You can also create a sparse matrix from a full matrix using the sparse function. Here's an example of how to convert a full 3x3 matrix B to a sparse matrix:

main.m
% Create a full 3x3 matrix
B = [1 0 0; 
     0 2 0; 
     0 0 3];
 
% Convert full matrix to sparse matrix
C = sparse(B);
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You can use various functions to manipulate sparse matrices such as find, nnz, speye, spdiags.