Update default SCF tolerance and change documentation

ChangeLog

@@ -3,6 +3,15 @@
 -Name
 -changes
 
+--------------
+Apr 08, 2023
+Name: Xin Jing
+Changes: (initialization.c)
+1. Change the default SCF tolerance for 1E-5 Ha/atom energy accuracy in single point calculation.
+2. Change the default SCF tolerance for 1E-3 Ha/bohr force accuracy in MD context.
+3. Change the default SCF tolerance for TOL_RELAX/5 Ha/bohr force accuracy in relaxation context.
+4. Update documentation.
+
 --------------
 Apr 03, 2023
 Name: Boqin Zhang

doc/.LaTeX/SCF.tex

@@ -190,7 +190,7 @@
 \end{block}
 
 \begin{block}{Default}
-Automatically set for $10^{-3}$ Ha/Bohr accuracy in force
+see description
 \end{block}
 
 \column{0.4\linewidth}
@@ -204,6 +204,9 @@
 \end{columns}
 
 \begin{block}{Description}
+In case of single point calculation, \texttt{TOL\_SCF} is set for $10^{-5}$ Ha/atom energy accuracy.
+In case of MD, \texttt{TOL\_SCF} is set for $10^{-3}$ Ha/Bohr force accuracy.
+In case of relaxation, \texttt{TOL\_SCF} is set for \hyperlink{TOL_RELAX}{\texttt{TOL\_RELAX}}/5 Ha/Bohr force accuracy. \\
 The tolerance on the normalized residual of the effective potential or the electron density for convergence of the SCF iteration. 
 \end{block}
 

src/initialization.c

@@ -2094,39 +2094,56 @@ void SPARC_copy_input(SPARC_OBJ *pSPARC, SPARC_INPUT_OBJ *pSPARC_Input) {
  // default SCF tolerance based on accuracy_level
  // we use a model curve to correlate scf tolerance and energy and force accuracy
  // log(y) = a * log(x) + b
- // (1) if y is energy accuracy (Ha/atom), a = 1.4312, b = -1.5225
- // (2) if y is force accuracy (Ha/Bohr), a = 0.9090, b = -0.9347
+ // y could be either energy accuracy (Ha/atom) or force accuracy (Ha/Bohr)
  // if scf tol is not set, we'll use accuracy_level to find scf tol
- if (pSPARC->TOL_SCF < 0.0) { 
- double target_force_accuracy = -1.0;
- double target_energy_accuracy = -1.0;
-
- // accuracy_levels : 0 - minimal | 1 - low | 2 - medium | 3 - high | 4 - extreme
- // target force accuracy: 0 - 1e-1 | 1 - 1e-2 | 2 - 1e-3 | 3 - 1e-4 | 4 - 1e-5
- if (pSPARC->accuracy_level >= 0) {
- target_force_accuracy = pow(10.0, -(pSPARC->accuracy_level + 1.0));
- } else if (pSPARC->target_force_accuracy > 0.0) {
- target_force_accuracy = pSPARC->target_force_accuracy;
- } else if (pSPARC->target_energy_accuracy > 0.0) {
- target_energy_accuracy = pSPARC->target_energy_accuracy;
- }
-
- // if none of the accuracy levels are specified, set force_accuracy to 1e-3
- if (target_force_accuracy < 0 && target_energy_accuracy < 0) {
- target_force_accuracy = 1e-3;
- }
-
- // calculate SCF TOL based on specified target accuracy
- if (target_force_accuracy > 0.0) { // find scf tol based on target force accuracy
- const double a = 0.9090;
- const double b = -0.9347;
+ // All models satisfy 90% dataset
+ if (pSPARC->TOL_SCF < 0.0) {
+ if (pSPARC->MDFlag != 0) {
+ // in case of MD, using 1E-3 Ha/Bohr force accuracy as target
+ double target_force_accuracy = 1E-3;
+ const double a = 1.025;
+ const double b = 1.368;
  double log_target = log(target_force_accuracy);
  pSPARC->TOL_SCF = exp((log_target - b)/a);
- } else if (target_energy_accuracy > 0.0) { // find scf tol based on target energy accuracy
- const double a = 1.4312;
- const double b = -1.5225;
- double log_target = log(target_energy_accuracy);
+ } else if (pSPARC->RelaxFlag != 0) {
+ // in case of relaxation, using TOL_RELAX/5 force accuracy as target
+ double target_force_accuracy = pSPARC->TOL_RELAX/5;
+ const double a = 1.025;
+ const double b = 1.468;
+ double log_target = log(target_force_accuracy);
  pSPARC->TOL_SCF = exp((log_target - b)/a);
+ } else {
+ // in case of single point calculation, using 1E-5 Ha/atom energy accuracy as target
+ double target_force_accuracy = -1.0;
+ double target_energy_accuracy = -1.0;
+
+ // accuracy_levels : 0 - minimal | 1 - low | 2 - medium | 3 - high | 4 - extreme
+ // target force accuracy: 0 - 1e-1 | 1 - 1e-2 | 2 - 1e-3 | 3 - 1e-4 | 4 - 1e-5
+ if (pSPARC->accuracy_level >= 0) {
+ target_force_accuracy = pow(10.0, -(pSPARC->accuracy_level + 1.0));
+ } else if (pSPARC->target_force_accuracy > 0.0) {
+ target_force_accuracy = pSPARC->target_force_accuracy;
+ } else if (pSPARC->target_energy_accuracy > 0.0) {
+ target_energy_accuracy = pSPARC->target_energy_accuracy;
+ }
+
+ // if none of the accuracy levels are specified, set energy_accuracy to 1e-5 Ha/atom
+ if (target_force_accuracy < 0 && target_energy_accuracy < 0) {
+ target_energy_accuracy = 1e-5;
+ }
+
+ // calculate SCF TOL based on specified target accuracy
+ if (target_energy_accuracy > 0.0) { // find scf tol based on target energy accuracy
+ const double a = 1.502;
+ const double b = 1.165;
+ double log_target = log(target_energy_accuracy);
+ pSPARC->TOL_SCF = exp((log_target - b)/a);
+ } else if (target_force_accuracy > 0.0) { // find scf tol based on target force accuracy
+ const double a = 1.025;
+ const double b = 1.368;
+ double log_target = log(target_force_accuracy);
+ pSPARC->TOL_SCF = exp((log_target - b)/a);
+ }
  }
  }
 
@@ -3137,7 +3154,7 @@ void write_output_init(SPARC_OBJ *pSPARC) {
  }
 
  fprintf(output_fp,"***************************************************************************\n");
- fprintf(output_fp,"* SPARC (version Apr 03, 2023) *\n");
+ fprintf(output_fp,"* SPARC (version Apr 08, 2023) *\n");
  fprintf(output_fp,"* Copyright (c) 2020 Material Physics & Mechanics Group, Georgia Tech *\n");
  fprintf(output_fp,"* Distributed under GNU General Public License 3 (GPL) *\n");
  fprintf(output_fp,"* Start time: %s *\n",c_time_str);