# nnz

## Purpose

Number of nonzero entries.

## Synopsis

    nz = nnz(X)

## Description

`nz = nnz(X)` is the number of nonzeros in matrix `X`.

The density of a sparse matrix, which is printed by the `whos` command, 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, issparse, nonzeros, nzmax, size, whos

(c) Copyright 1994 by The MathWorks, Inc.