def _update_dprx(self):
super(ExpCM_empirical_phi, self)._update_dprx()<EOL>if '<STR_LIT>' in self.freeparams:<EOL><INDENT>dphi_over_phi = scipy.zeros(N_CODON, dtype='<STR_LIT:float>')<EOL>for j in range(<NUM_LIT:3>):<EOL><INDENT>dphi_over_phi += (self.dphi_dbeta / self.phi)[CODON_NT_INDEX[j]]<EOL><DEDENT>for r in range(self.nsites):<EOL><INDENT>self.dprx['<STR_LIT>'][r] += self.prx[r] * (dphi_over_phi<EOL>- scipy.dot(dphi_over_phi, self.prx[r]))<EOL><DEDENT><DEDENT>
Update `dprx`, accounting for dependence of `phi` on `beta`.