sparse - sparse matrix definition
sparse is used to build a sparse matrix. Only non-zero entries are stored.
sp = sparse(X) converts a full matrix to sparse form by squeezing out any zero elements. (If X is already sparse sp is X).
sp=sparse(ij,v [,mn]) builds an mn(1)-by-mn(2) sparse matrix with sp(ij(k,1),ij(k,2))=v(k). ij and v must have the same column dimension. If optional mn parameter is not given the sp matrix dimensions are the max value of ij(:,1) and ij(:,2) respectively.
Operations (concatenation, addition, etc,) with sparse matrices are made using the same syntax as for full matrices.
Elementary functions are also available (abs,maxi,sum,diag,...) for sparse matrices.
Mixed operations (full-sparse) are allowed. Results are full or sparse depending on the operations.
sp=sparse([1,2;4,5;3,10],[1,2,3]) size(sp) x=rand(2,2);abs(x)-full(abs(sparse(x)))