nnz

nnz — number of non zero entries in a matrix

Calling sequence

n=nnz(X)

`X`	: real or complex sparse (or full) matrix
`n`	: integer, the number of non zero elements in X

nnz counts the number of non zero entries in a sparse or full matrix



sp=sparse([1,2;4,5;3,10],[1,2,3]);
nnz(sp)
a=[1 0 0 0 2];
nnz(a)