def sparse_mean_var(data):
data = sparse.csc_matrix(data)<EOL>return sparse_means_var_csc(data.data,<EOL>data.indices,<EOL>data.indptr,<EOL>data.shape[<NUM_LIT:1>],<EOL>data.shape[<NUM_LIT:0>])<EOL>
Calculates the variance for each row of a sparse matrix,
using the relationship Var = E[x^2] - E[x]^2.

Returns:
    pair of matrices mean, variance.