nnz - Number of nonzero matrix elements

Syntax

Description

n = nnz(X) returns the number of nonzero elements in matrix X.

The density of a sparse matrix is nnz(X)/prod(size(X)).

Examples

The matrix

 w = sparse(wilkinson(21));

is a tridiagonal matrix with 20 nonzeros on each of three diagonals, so nnz(w) = 60.

See Also

find | isa | nonzeros | nzmax | size | whos

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