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Number of nonzero matrix elements
n=nnz(X)
n = nnz(X)
returns the number of nonzero elements in matrix X.
The density of a sparse matrix is nnz(X)/prod(size(X)).
The matrix
w = sparse(wilkinson(21));
is a tridiagonal matrix with 20 nonzeros on each of three diagonals, so nnz(w) = 60.
find Find indices and values of nonzero elements
nonzeros Nonzero matrix elements
nzmax Amount of storage allocated for nonzero matrix
elements
size Array dimensions
whos List directory of variables in memory
isa Detect an object of a given class