def characterize_psf(self):
l,u = max(self.zrange[<NUM_LIT:0>], self.param_dict['<STR_LIT>']), self.zrange[<NUM_LIT:1>]<EOL>size_l, drift_l = self.measure_size_drift(l, size=self.support)<EOL>size_u, drift_u = self.measure_size_drift(u, size=self.support)<EOL>self.drift_poly = np.polyfit([l, u], [drift_l, drift_u], <NUM_LIT:1>)<EOL>
Get support size and drift polynomial for current set of params