def d(self, p):
if p not in self._d:<EOL><INDENT>est = _onenormest_matrix_power(self._A, p, self._ell)<EOL>self._d[p] = est ** (<NUM_LIT:1.0> / p)<EOL><DEDENT>return self._d[p]<EOL>
Lazily estimate d_p(A) ~= || A^p ||^(1/p) where ||.|| is the 1-norm.