def _eta_from_phi(self):
self.eta = scipy.ndarray(N_NT - <NUM_LIT:1>, dtype='<STR_LIT:float>')<EOL>etaprod = <NUM_LIT:1.0><EOL>for w in range(N_NT - <NUM_LIT:1>):<EOL><INDENT>self.eta[w] = <NUM_LIT:1.0> - self.phi[w] / etaprod<EOL>etaprod *= self.eta[w]<EOL><DEDENT>_checkParam('<STR_LIT>', self.eta, self.PARAMLIMITS, self.PARAMTYPES)<EOL>
Update `eta` using current `phi`.