Fixing argument errors and adding note on datafiles to doc

doc/src/pair_gran.rst

@@ -279,6 +279,11 @@ statistically similar results.  This is because the forces they
 compute depend on atom velocities.  See the
 :doc:`read_restart <read_restart>` command for more details.
 
+Accumulated values for individual contacts are saved to to restart
+files but are not saved to data files. Therefore, forces may
+differ significantly when a system is reloaded using A
+:doc:`read_data <read_data>` command.
+
 Related commands
 """"""""""""""""
 

doc/src/pair_granular.rst

@@ -780,6 +780,11 @@ statistically similar results.  This is because the forces they
 compute depend on atom velocities.  See the
 :doc:`read_restart <read_restart>` command for more details.
 
+Accumulated values for individual contacts are saved to to restart
+files but are not saved to data files. Therefore, forces may
+differ significantly when a system is reloaded using A
+:doc:`read_data <read_data>` command.
+
 Related commands
 """"""""""""""""
 

src/GRANULAR/contact_tangential_models.cpp

@@ -168,7 +168,7 @@ void TangentialLinearHistory::calculate_forces()
 
 TangentialLinearHistoryClassic::TangentialLinearHistoryClassic(LAMMPS *lmp) : TangentialLinearHistory(lmp)
 {
-  scale_area = 0;
+  scale_area = 0; // Sets gran/hooke/history behavior
 }
 
 /* ---------------------------------------------------------------------- */
@@ -233,7 +233,7 @@ void TangentialLinearHistoryClassic::calculate_forces()
 
 TangentialMindlinClassic::TangentialMindlinClassic(LAMMPS *lmp) : TangentialLinearHistoryClassic(lmp)
 {
-  scale_area = 1;
+  scale_area = 1; // Sets gran/hertz/history behavior
 }
 
 /* ----------------------------------------------------------------------

src/GRANULAR/contact_twisting_models.cpp

@@ -50,7 +50,6 @@ TwistingMarshall::TwistingMarshall(LAMMPS *lmp) : TwistingModel(lmp)
 void TwistingMarshall::init()
 {
   k_tang = contact->tangential_model->k;
-  damp_tang = contact->tangential_model->damp;
   mu_tang = contact->tangential_model->mu;
 }
 
@@ -63,7 +62,7 @@ void TwistingMarshall::calculate_forces()
   // Calculate twist coefficients from tangential model & contact geometry
   // eq 32 of Marshall paper
   double k = 0.5 * k_tang * contact->area * contact->area;
-  double damp = 0.5 * damp_tang * contact->area * contact->area;
+  double damp = 0.5 * contact->tangential_model->damp * contact->area * contact->area;
   double mu = TWOTHIRDS * mu_tang * contact->area;
 
   if (contact->history_update) {

src/GRANULAR/contact_twisting_models.h

@@ -44,7 +44,7 @@ class TwistingMarshall : public TwistingModel {
   void calculate_forces();
   void init();
  protected:
-  double k_tang, damp_tang, mu_tang;
+  double k_tang, mu_tang;
 };
 
 /* ---------------------------------------------------------------------- */

src/GRANULAR/fix_wall_gran.cpp

@@ -83,8 +83,7 @@ FixWallGran::FixWallGran(LAMMPS *lmp, int narg, char **arg) :
 
   int iarg;
   if (classic_flag) {
-    iarg = 4;
-    iarg = model->init_classic_model(arg, iarg, narg);
+    iarg = model->init_classic_model(arg, 3, narg);
 
     if (iarg < narg) {
       if (strcmp(arg[iarg],"limit_damping") == 0) {

src/GRANULAR/pair_granular.cpp

@@ -354,7 +354,8 @@ void PairGranular::coeff(int narg, char **arg)
 
   while (iarg < narg) {
 
-    if (strcmp(arg[iarg++], "tangential") == 0) {
+    if (strcmp(arg[iarg], "tangential") == 0) {
+      iarg++;
       if (iarg >= narg)
         error->all(FLERR,"Illegal pair_coeff command, must specify "
             "tangential model after tangential keyword");