### 41.9 Matrix Properties

Function: size_t gsl_spmatrix_nnz (const gsl_spmatrix * m)

  This function returns the number of non-zero elements in m.

Function: int gsl_spmatrix_equal (const gsl_spmatrix * a, const gsl_spmatrix * b)

  This function returns 1 if the matrices a and b are equal (by comparison of element values) and 0 otherwise. The matrices a and b must be in the same sparse storage format for comparison.