update description of scf_thr_type

Author: QuantumMisaka

docs/advanced/input_files/input-main.md

@@ -20,8 +20,8 @@
     - [kspacing](#kspacing)
     - [min\_dist\_coef](#min_dist_coef)
     - [device](#device)
-    - [nb2d](#nb2d)
     - [precision](#precision)
+    - [nb2d](#nb2d)
   - [Variables related to input files](#variables-related-to-input-files)
     - [stru\_file](#stru_file)
     - [kpoint\_file](#kpoint_file)
@@ -224,6 +224,8 @@
     - [of\_ml\_q](#of_ml_q)
     - [of\_ml\_tanhp](#of_ml_tanhp)
     - [of\_ml\_tanhq](#of_ml_tanhq)
+    - [of\_ml\_chi\_p](#of_ml_chi_p)
+    - [of\_ml\_chi\_q](#of_ml_chi_q)
     - [of\_ml\_gammanl](#of_ml_gammanl)
     - [of\_ml\_pnl](#of_ml_pnl)
     - [of\_ml\_qnl](#of_ml_qnl)
@@ -234,8 +236,6 @@
     - [of\_ml\_tanh\_qnl](#of_ml_tanh_qnl)
     - [of\_ml\_tanhp\_nl](#of_ml_tanhp_nl)
     - [of\_ml\_tanhq\_nl](#of_ml_tanhq_nl)
-    - [of\_ml\_chi\_p](#of_ml_chi_p)
-    - [of\_ml\_chi\_q](#of_ml_chi_q)
     - [of\_ml\_chi\_xi](#of_ml_chi_xi)
     - [of\_ml\_chi\_pnl](#of_ml_chi_pnl)
     - [of\_ml\_chi\_qnl](#of_ml_chi_qnl)
@@ -1246,10 +1246,8 @@ Note: In new angle mixing, you should set `mixing_beta_mag >> mixing_beta`. The
 
 - **Type**: Integer
 - **Description**: Choose the calculation method of convergence criterion.
-  - **1**: the criterion is defined as $\Delta\rho_G = \frac{1}{2}\iint{\frac{\Delta\rho(r)\Delta\rho(r')}{|r-r'|}d^3r d^3r'}$.
-  - **2**: the criterion is defined as $\Delta\rho_R = \frac{1}{N_e}\int{|\Delta\rho(r)|d^3r}$, where $N_e$ is the number of electron.
-
-  Note: This parameter is still under testing and the default setting is usually sufficient.
+  - **1**: the criterion is defined as $\Delta\rho_G = \frac{1}{2}\iint{\frac{\Delta\rho(r)\Delta\rho(r')}{|r-r'|}d^3r d^3r'}$, which is used in SCF of PW basis with unit Ry. 
+  - **2**: the criterion is defined as $\Delta\rho_R = \frac{1}{N_e}\int{|\Delta\rho(r)|d^3r}$, where $N_e$ is the number of electron, which is used in SCF of LCAO without any unit.
 
 - **Default**: 1 (plane-wave basis), or 2 (localized atomic orbital basis).