Added vel keyword to fix_styles wall_lj93 and wall_lj126

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@2151 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/fix_wall_lj126.txt

@@ -10,7 +10,7 @@ fix wall/lj126 command :h3
 
 [Syntax:]
 
-fix ID group-ID wall/lj126 style coord epsilon sigma cutoff :pre
+fix ID group-ID wall/lj126 style coord epsilon sigma cutoff keyword values ... :pre
 
 ID, group-ID are documented in "fix"_fix.html command
 wall/lj126 = style name of this fix command
@@ -19,10 +19,16 @@ coord = position of wall
 epsilon = Lennard-Jones epsilon for wall-particle interaction
 sigma = Lennard-Jones sigma for wall-particle interaction
 cutoff = distance from wall at which wall-particle interaction is cut off :ul
+one or more keyword/value pairs may be appended :l
+keyword = {vel} :l
+  {vel} args = v
+    v = velocity of wall (velocity units)
+:ule
 
 [Examples:]
 
 fix wallhi all wall/lj126 xhi 10.0 1.0 1.0 1.12 :pre
+fix leftwall all wall/lj126 zlo 0.0  1.0 1.0 0.858 vel 1.0
 
 [Description:]
 
@@ -41,6 +47,12 @@ provided by the "fix wall/lj93"_fix_wall_lj93.html command.
 The wall potential is shifted so that the energy of a wall-particle
 interaction is 0.0 at the cutoff distance.
 
+If the {vel} keyword is specified, the position of wall will move during the
+simulation, based on its initial position (coord) and the specified
+velocity (vel).  Note that if you do multiple runs, the initial position
+of the indenter (x,y,z) does not change, so it will continue to move
+at the specified velocity.
+
 [Restart, fix_modify, output, run start/stop, minimize info:]
 
 No information about this fix is written to "binary restart
@@ -77,4 +89,7 @@ Any dimension (xyz) that has a LJ 12/6 wall must be non-periodic.
 "fix wall/reflect"_fix_wall_reflect.html, "fix
 wall/lj93"_fix_wall_lj93.html
 
-[Default:] none
+[Default:]
+
+The option defaults are vel = 0.
+

doc/fix_wall_lj93.txt

@@ -10,7 +10,7 @@ fix wall/lj93 command :h3
 
 [Syntax:]
 
-fix ID group-ID wall/lj93 style coord epsilon sigma cutoff :pre
+fix ID group-ID wall/lj93 style coord epsilon sigma cutoff keyword values ... :pre
 
 ID, group-ID are documented in "fix"_fix.html command
 wall/lj93 = style name of this fix command
@@ -18,11 +18,17 @@ style = {xlo} or {xhi} or {ylo} or {yhi} or {zlo} or {zhi}
 coord = position of wall
 epsilon = Lennard-Jones epsilon for wall-particle interaction
 sigma = Lennard-Jones sigma for wall-particle interaction
-cutoff = distance from wall at which wall-particle interaction is cut off :ul
+cutoff = distance from wall at which wall-particle interaction is cut off :l
+one or more keyword/value pairs may be appended :l
+keyword = {vel} :l
+  {vel} args = v
+    v = velocity of wall (velocity units)
+:ule
 
 [Examples:]
 
 fix wallhi all wall/lj93 xhi 10.0 1.0 1.0 2.5 :pre
+fix leftwall all wall/lj93 zlo 0.0  1.0 1.0 0.858 vel 1.0
 
 [Description:]
 
@@ -42,6 +48,12 @@ wall/lj126"_fix_wall_lj126.html command.
 The wall potential is shifted so that the energy of a wall-particle
 interaction is 0.0 at the cutoff distance.
 
+If the {vel} keyword is specified, the position of wall will move during the
+simulation, based on its initial position (coord) and the specified
+velocity (vel).  Note that if you do multiple runs, the initial position
+of the indenter (x,y,z) does not change, so it will continue to move
+at the specified velocity.
+
 [Restart, fix_modify, output, run start/stop, minimize info:]
 
 No information about this fix is written to "binary restart
@@ -78,4 +90,7 @@ Any dimension (xyz) that has a LJ 9/3 wall must be non-periodic.
 "fix wall/reflect"_fix_wall_reflect.html, "fix
 wall/lj126"_fix_wall_lj126.html
 
-[Default:] none
+[Default:]
+
+The option defaults are vel = 0.
+

src/fix_wall_lj126.cpp

@@ -33,7 +33,7 @@ using namespace LAMMPS_NS;
 FixWallLJ126::FixWallLJ126(LAMMPS *lmp, int narg, char **arg) :
   Fix(lmp, narg, arg)
 {
-  if (narg != 8) error->all("Illegal fix wall/lj126 command");
+  if (narg < 8) error->all("Illegal fix wall/lj126 command");
 
   scalar_flag = 1;
   vector_flag = 1;
@@ -42,7 +42,11 @@ FixWallLJ126::FixWallLJ126(LAMMPS *lmp, int narg, char **arg) :
   extscalar = 1;
   extvector = 1;
 
-  if (strcmp(arg[3],"xlo") == 0) {
+  // set defaults
+
+  vel = 0.0;
+
+if (strcmp(arg[3],"xlo") == 0) {
     dim = 0;
     side = -1;
   } else if (strcmp(arg[3],"xhi") == 0) {
@@ -62,11 +66,20 @@ FixWallLJ126::FixWallLJ126(LAMMPS *lmp, int narg, char **arg) :
     side = 1;
   } else error->all("Illegal fix wall/lj126 command");
 
-  coord = atof(arg[4]);
+  coord0 = atof(arg[4]);
   epsilon = atof(arg[5]);
   sigma = atof(arg[6]);
   cutoff = atof(arg[7]);
 
+  int iarg = 8;
+  while (iarg < narg) {
+    if (strcmp(arg[iarg],"vel") == 0) {
+      if (iarg+2 > narg) error->all("Illegal fix wall/lj126 command");
+      vel = atof(arg[iarg+1]);
+      iarg += 2;
+    } else error->all("Illegal fix wall/lj126 command");
+  }
+
   coeff1 = 48.0 * epsilon * pow(sigma,12.0);
   coeff2 = 24.0 * epsilon * pow(sigma,6.0);
   coeff3 = 4.0 * epsilon * pow(sigma,12.0);
@@ -140,6 +153,13 @@ void FixWallLJ126::post_force(int vflag)
   wall[0] = wall[1] = wall[2] = wall[3] = 0.0;
   wall_flag = 0;
 
+  // coord = current position of wall
+  // coord0 = initial position of wall
+  
+  double delt = (update->ntimestep - update->beginstep) * update->dt;
+  double coord = coord0 + delt*vel;
+
+
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit) {
       if (side == -1) delta = x[i][dim] - coord;

src/fix_wall_lj126.h

@@ -36,6 +36,7 @@ class FixWallLJ126 : public Fix {
   double coord,epsilon,sigma,cutoff;
   double coeff1,coeff2,coeff3,coeff4,offset;
   double wall[4],wall_all[4];
+  double vel,coord0;
   int wall_flag;
   int nlevels_respa;
 };

src/fix_wall_lj93.cpp

@@ -29,7 +29,7 @@ using namespace LAMMPS_NS;
 FixWallLJ93::FixWallLJ93(LAMMPS *lmp, int narg, char **arg) :
   Fix(lmp, narg, arg)
 {
-  if (narg != 8) error->all("Illegal fix wall/lj93 command");
+  if (narg < 8) error->all("Illegal fix wall/lj93 command");
 
   scalar_flag = 1;
   vector_flag = 1;
@@ -38,6 +38,10 @@ FixWallLJ93::FixWallLJ93(LAMMPS *lmp, int narg, char **arg) :
   extscalar = 1;
   extvector = 1;
 
+  // set defaults
+
+  vel = 0.0;
+
   if (strcmp(arg[3],"xlo") == 0) {
     dim = 0;
     side = -1;
@@ -58,11 +62,20 @@ FixWallLJ93::FixWallLJ93(LAMMPS *lmp, int narg, char **arg) :
     side = 1;
   } else error->all("Illegal fix wall/lj93 command");
 
-  coord = atof(arg[4]);
+  coord0 = atof(arg[4]);
   epsilon = atof(arg[5]);
   sigma = atof(arg[6]);
   cutoff = atof(arg[7]);
 
+  int iarg = 8;
+  while (iarg < narg) {
+    if (strcmp(arg[iarg],"vel") == 0) {
+      if (iarg+2 > narg) error->all("Illegal fix wall/lj93 command");
+      vel = atof(arg[iarg+1]);
+      iarg += 2;
+    } else error->all("Illegal fix wall/lj93 command");
+  }
+
   coeff1 = 6.0/5.0 * epsilon * pow(sigma,9.0);
   coeff2 = 3.0 * epsilon * pow(sigma,3.0);
   coeff3 = 2.0/15.0 * epsilon * pow(sigma,9.0);
@@ -137,6 +150,12 @@ void FixWallLJ93::post_force(int vflag)
   wall[0] = wall[1] = wall[2] = wall[3] = 0.0;
   wall_flag = 0;
 
+  // coord = current position of wall
+  // coord0 = initial position of wall
+
+  double delt = (update->ntimestep - update->beginstep) * update->dt;
+  double coord = coord0 + delt*vel;
+
   for (int i = 0; i < nlocal; i++)
     if (mask[i] & groupbit) {
       if (side == -1) delta = x[i][dim] - coord;

src/fix_wall_lj93.h

@@ -37,6 +37,7 @@ class FixWallLJ93 : public Fix {
   double coord,epsilon,sigma,cutoff;
   double coeff1,coeff2,coeff3,coeff4,offset;
   double wall[4],wall_all[4];
+  double vel,coord0;
   int wall_flag;
   int nlevels_respa;
 };