def remove_negative_entries(A):
    r"""Remove all negative entries from sparse matrix.

        Aplus=max(0, A)

    Parameters
    ----------
    A : (M, M) scipy.sparse matrix
        Input matrix

    Returns
    -------
    Aplus : (M, M) scipy.sparse matrix
        Input matrix with negative entries set to zero.

    """
    A = A.tocoo()

    data = A.data
    row = A.row
    col = A.col

    """Positive entries"""
    pos = data > 0.0

    datap = data[pos]
    rowp = row[pos]
    colp = col[pos]

    Aplus = coo_matrix((datap, (rowp, colp)), shape=A.shape)
    return Aplus