MATLAB Function Reference |

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**

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 |