git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9222 f3b2605a-c512-4ea7-a41b-209d697bcdaa

src/fix_external.cpp

@@ -13,6 +13,7 @@
 
 #include "stdio.h"
 #include "string.h"
+#include "stdlib.h"
 #include "fix_external.h"
 #include "atom.h"
 #include "update.h"
@@ -22,23 +23,47 @@
 using namespace LAMMPS_NS;
 using namespace FixConst;
 
+enum{PF_CALLBACK,PF_ARRAY};
+
 /* ---------------------------------------------------------------------- */
 
 FixExternal::FixExternal(LAMMPS *lmp, int narg, char **arg) :
   Fix(lmp, narg, arg)
 {
-  if (narg != 3) error->all(FLERR,"Illegal fix external command");
+  if (narg < 4) error->all(FLERR,"Illegal fix external command");
+
+  if (strcmp(arg[3],"pf/callback") == 0) {
+    if (narg != 6) error->all(FLERR,"Illegal fix external command");
+    mode = PF_CALLBACK;
+    ncall = atoi(arg[4]);
+    napply = atoi(arg[5]);
+    if (ncall <= 0 || napply <= 0) 
+      error->all(FLERR,"Illegal fix external command");
+  } else if (strcmp(arg[3],"pf/array") == 0) {
+    if (narg != 5) error->all(FLERR,"Illegal fix external command");
+    mode = PF_ARRAY;
+    napply = atoi(arg[4]);
+    if (napply <= 0) error->all(FLERR,"Illegal fix external command");
+  } else error->all(FLERR,"Illegal fix external command");
 
   callback = NULL;
 
-  nmax = 0;
+  // perform initial allocation of atom-based array
+  // register with Atom class
+
   fexternal = NULL;
+  grow_arrays(atom->nmax);
+  atom->add_callback(0);
 }
 
 /* ---------------------------------------------------------------------- */
 
 FixExternal::~FixExternal()
 {
+  // unregister callbacks to this fix from Atom class
+
+  atom->delete_callback(id,0);
+
   memory->destroy(fexternal);
 }
 
@@ -47,8 +72,10 @@ FixExternal::~FixExternal()
 int FixExternal::setmask()
 {
   int mask = 0;
-  mask |= POST_FORCE;
-  mask |= MIN_POST_FORCE;
+  if (mode == PF_CALLBACK || mode == PF_ARRAY) {
+    mask |= POST_FORCE;
+    mask |= MIN_POST_FORCE;
+  }
   return mask;
 }
 
@@ -56,7 +83,7 @@ int FixExternal::setmask()
 
 void FixExternal::init()
 {
-  if (callback == NULL)
+  if (mode == PF_CALLBACK && callback == NULL)
     error->all(FLERR,"Fix external callback function not set");
 }
 
@@ -78,30 +105,29 @@ void FixExternal::min_setup(int vflag)
 
 void FixExternal::post_force(int vflag)
 {
-  if (atom->nlocal > nmax) {
-    memory->destroy(fexternal);
-    nmax = atom->nmax;
-    memory->create(fexternal,nmax,3,"external:fexternal");
-  }
+  bigint ntimestep = update->ntimestep;
 
   // invoke the callback in driver program
   // it will fill fexternal with forces
 
-  (this->callback)(ptr_caller,update->ntimestep,
-                   atom->nlocal,atom->tag,atom->x,fexternal);
+  if (mode == PF_CALLBACK && ntimestep & ncall == 0)
+    (this->callback)(ptr_caller,update->ntimestep,
+                     atom->nlocal,atom->tag,atom->x,fexternal);
 
   // add forces from fexternal to atoms in group
 
-  double **f = atom->f;
-  int *mask = atom->mask;
-  int nlocal = atom->nlocal;
+  if (ntimestep & napply == 0) {
+    double **f = atom->f;
+    int *mask = atom->mask;
+    int nlocal = atom->nlocal;
 
-  for (int i = 0; i < nlocal; i++)
-    if (mask[i] & groupbit) {
-      f[i][0] += fexternal[i][0];
-      f[i][1] += fexternal[i][1];
-      f[i][2] += fexternal[i][2];
-    }
+    for (int i = 0; i < nlocal; i++)
+      if (mask[i] & groupbit) {
+        f[i][0] += fexternal[i][0];
+        f[i][1] += fexternal[i][1];
+        f[i][2] += fexternal[i][2];
+      }
+  }
 }
 
 /* ---------------------------------------------------------------------- */
@@ -111,6 +137,60 @@ void FixExternal::min_post_force(int vflag)
   post_force(vflag);
 }
 
+/* ----------------------------------------------------------------------
+   memory usage of local atom-based array
+------------------------------------------------------------------------- */
+
+double FixExternal::memory_usage()
+{
+  double bytes = 3*atom->nmax * sizeof(double);
+  return bytes;
+}
+
+/* ----------------------------------------------------------------------
+   allocate atom-based array
+------------------------------------------------------------------------- */
+
+void FixExternal::grow_arrays(int nmax)
+{
+  memory->grow(fexternal,nmax,3,"external:fexternal");
+}
+
+/* ----------------------------------------------------------------------
+   copy values within local atom-based array
+------------------------------------------------------------------------- */
+
+void FixExternal::copy_arrays(int i, int j)
+{
+  fexternal[j][0] = fexternal[i][0];
+  fexternal[j][1] = fexternal[i][1];
+  fexternal[j][2] = fexternal[i][2];
+}
+
+/* ----------------------------------------------------------------------
+   pack values in local atom-based array for exchange with another proc
+------------------------------------------------------------------------- */
+
+int FixExternal::pack_exchange(int i, double *buf)
+{
+  buf[0] = fexternal[i][0];
+  buf[1] = fexternal[i][1];
+  buf[2] = fexternal[i][2];
+  return 3;
+}
+
+/* ----------------------------------------------------------------------
+   unpack values in local atom-based array from exchange with another proc
+------------------------------------------------------------------------- */
+
+int FixExternal::unpack_exchange(int nlocal, double *buf)
+{
+  fexternal[nlocal][0] = buf[0];
+  fexternal[nlocal][1] = buf[1];
+  fexternal[nlocal][2] = buf[2];
+  return 3;
+}
+
 /* ----------------------------------------------------------------------
    external caller sets a callback function to invoke in post_force()
 ------------------------------------------------------------------------- */
@@ -120,3 +200,4 @@ void FixExternal::set_callback(FnPtr caller_callback, void *caller_ptr)
   callback = caller_callback;
   ptr_caller = caller_ptr;
 }
+

src/fix_external.h

@@ -35,10 +35,17 @@ class FixExternal : public Fix {
   void post_force(int);
   void min_post_force(int);
 
+  double memory_usage();
+  void grow_arrays(int);
+  void copy_arrays(int, int);
+  int pack_exchange(int, double *);
+  int unpack_exchange(int, double *);
+
   typedef void (*FnPtr)(void *, int, int, int *, double **, double **);
   void set_callback(FnPtr, void *);
 
  private:
+  int mode,ncall,napply;
   FnPtr callback;
   void *ptr_caller;
   int nmax;