added doublet ratio criteria for rejecting false positives

qsoabsfind/absfinder.py

@@ -228,8 +228,11 @@ def convolution_method_absorber_finder_in_QSO_spectra(spec_index, absorber='MgII
                         vel1, vel2 = vel_dispersion(c0, c1, gaussian_parameters[2], gaussian_parameters[5], resolution)
                         # calculate best -fit doublet ratio and errors and check if they are within the range.
                         # usually 1 < DR < f1/f2 (doublet ratio =2, for MgII, CIV)
-                        dr, dr_error = calculate_doublet_ratio(EW_first_temp_mean[0], EW_second_temp_mean[0], EW_first_error_temp[0], EW_second_error_temp[0])
-                        min_dr, max_dr = 1 - 2 * dr_error, f1/f2 + 2 * dr_error
+                        if EW_first_temp_mean[0] > 0 and EW_second_temp_mean[0] > 0:
+                            dr, dr_error = calculate_doublet_ratio(EW_first_temp_mean[0], EW_second_temp_mean[0], EW_first_error_temp[0], EW_second_error_temp[0])
+                            min_dr, max_dr = 1 - 2 * dr_error, f1/f2 + 2 * dr_error
+                        else:
+                            dr, min_dr, max_dr = -1, -1, -1 #failure case
 
                         if (gaussian_parameters > bound[0] + 0.01).all() and (gaussian_parameters < bound[1] - 0.01).all() and lower_del_lam <= c1 - c0 <= upper_del_lam and sn1 > sn_line1 and sn2 > sn_line2 and vel1 > 0 and vel2 > 0 and min_dr <= dr <=max_dr:
                             pure_z_abs[m] = z_new

qsoabsfind/absorberutils.py

@@ -104,9 +104,6 @@ def calculate_doublet_ratio(ew1, ew2, ew1_error, ew2_error):
             - doublet_ratio (float): The ratio of ew1 to ew2.
             - doublet_ratio_error (float): The propagated error for the doublet ratio.
     """
-    if ew2 == 0:
-        raise ValueError("ew2 cannot be zero, as it would result in division by zero.")
-
     # Calculate the doublet ratio
     doublet_ratio = ew1 / ew2