def _update_prx(self):
qx = scipy.ones(N_CODON, dtype='<STR_LIT:float>')<EOL>for j in range(<NUM_LIT:3>):<EOL><INDENT>for w in range(N_NT):<EOL><INDENT>qx[CODON_NT[j][w]] *= self.phi[w]<EOL><DEDENT><DEDENT>frx = self.pi_codon**self.beta<EOL>self.prx = frx * qx<EOL>with scipy.errstate(divide='<STR_LIT>', under='<STR_LIT>', over='<STR_LIT>',<EOL>invalid='<STR_LIT>'):<EOL><INDENT>for r in range(self.nsites):<EOL><INDENT>self.prx[r] /= self.prx[r].sum()<EOL><DEDENT><DEDENT>
Update `prx` from `phi`, `pi_codon`, and `beta`.