def _update_phi(self):
self.phi = self._compute_empirical_phi(self.beta)<EOL>_checkParam('<STR_LIT>', self.phi, self.PARAMLIMITS, self.PARAMTYPES)<EOL>self._eta_from_phi()<EOL>dbeta = <NUM_LIT><EOL>self.dphi_dbeta = scipy.misc.derivative(self._compute_empirical_phi,<EOL>self.beta, dx=dbeta, n=<NUM_LIT:1>, order=<NUM_LIT:5>)<EOL>dphi_dbeta_halfdx = scipy.misc.derivative(self._compute_empirical_phi,<EOL>self.beta, dx=dbeta / <NUM_LIT:2>, n=<NUM_LIT:1>, order=<NUM_LIT:5>)<EOL>assert scipy.allclose(self.dphi_dbeta, dphi_dbeta_halfdx, atol=<NUM_LIT>,<EOL>rtol=<NUM_LIT>), ("<STR_LIT>"<EOL>"<STR_LIT>"<EOL>"<STR_LIT>").format(<EOL>dbeta, self.dphi_dbeta, dphi_dbeta_halfdx)<EOL>
Compute `phi`, `dphi_dbeta`, and `eta` from `g` and `frxy`.