code: def _rand1(self):
          "generate a single random sample"
          Z = _unwhiten_cf(self._S_cf, self._genA())
          return Z.dot(Z.Tf _rand1(self):
          "generate a single random sample"
          Z = _unwhiten_cf(self._S_cf, self._genA())
          return Z.dot(Z.T)
docs: generate a single random sample