MATLAB Function Reference

nnz

Number of nonzero matrix elements

Syntax

• n = nnz(X)
  

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

nnls

noanimate