def nb_ll_row(params, data_row):
p = params[<NUM_LIT:0>]<EOL>r = params[<NUM_LIT:1>]<EOL>n = len(data_row)<EOL>ll = np.sum(gammaln(data_row + r)) - np.sum(gammaln(data_row + <NUM_LIT:1>))<EOL>ll -= n*gammaln(r)<EOL>ll += np.sum(data_row)*np.log(p)<EOL>ll += n*r*np.log(<NUM_LIT:1>-p)<EOL>return -ll<EOL>
returns the negative LL of a single row.

Args:
    params (array) - [p, r]
    data_row (array) - 1d array of data

Returns:
    LL of row