From 21c24459c92c88391e387a85ae3780785c126ca4 Mon Sep 17 00:00:00 2001
From: sjplimp <sjplimp@f3b2605a-c512-4ea7-a41b-209d697bcdaa>
Date: Thu, 1 Dec 2011 00:08:08 +0000
Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@7244
 f3b2605a-c512-4ea7-a41b-209d697bcdaa

---
 src/fix_dt_reset.cpp | 34 +++++++++++++++++++++++-----------
 src/fix_dt_reset.h   |  3 ++-
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/src/fix_dt_reset.cpp b/src/fix_dt_reset.cpp
index 758c8b32a5..c35903a69b 100644
--- a/src/fix_dt_reset.cpp
+++ b/src/fix_dt_reset.cpp
@@ -43,7 +43,7 @@ FixDtReset::FixDtReset(LAMMPS *lmp, int narg, char **arg) :
   time_depend = 1;
   scalar_flag = 1;
   vector_flag = 1;
-  size_vector = 1;
+  size_vector = 2;
   global_freq = 1;
   extscalar = 0;
   extvector = 0;
@@ -86,7 +86,7 @@ FixDtReset::FixDtReset(LAMMPS *lmp, int narg, char **arg) :
 
   // initializations
 
-  t_elapsed = 0.0;
+  t_elapsed = t_laststep = 0.0;
   laststep = update->ntimestep;
 }
 
@@ -95,6 +95,7 @@ FixDtReset::FixDtReset(LAMMPS *lmp, int narg, char **arg) :
 int FixDtReset::setmask()
 {
   int mask = 0;
+  mask |= INITIAL_INTEGRATE;
   mask |= END_OF_STEP;
   return mask;
 }
@@ -113,9 +114,11 @@ void FixDtReset::init()
   for (int i = 0; i < output->ndump; i++)
     if ((strcmp(output->dump[i]->style,"dcd") == 0 ||
 	strcmp(output->dump[i]->style,"xtc") == 0) && comm->me == 0)
-      error->warning(FLERR,"Dump dcd/xtc timestamp may be wrong with fix dt/reset");
+      error->warning(FLERR,
+		     "Dump dcd/xtc timestamp may be wrong with fix dt/reset");
 
   ftm2v = force->ftm2v;
+  dt = update->dt;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -127,16 +130,21 @@ void FixDtReset::setup(int vflag)
 
 /* ---------------------------------------------------------------------- */
 
+void FixDtReset::initial_integrate(int vflag)
+{
+  // calculate elapsed time based on previous reset timestep
+
+  t_elapsed = t_laststep + (update->ntimestep-laststep)*dt;
+}
+
+/* ---------------------------------------------------------------------- */
+
 void FixDtReset::end_of_step()
 {
-  double dt,dtv,dtf,dtsq;
+  double dtv,dtf,dtsq;
   double vsq,fsq,massinv;
   double delx,dely,delz,delr;
 
-  // accumulate total time based on previous timestep
-
-  t_elapsed += (update->ntimestep - laststep) * update->dt;
-
   // compute vmax and amax of any atom in group
 
   double **v = atom->v;
@@ -173,12 +181,15 @@ void FixDtReset::end_of_step()
   if (minbound) dt = MAX(dt,tmin);
   if (maxbound) dt = MIN(dt,tmax);
   
-  // reset update->dt and other classes that depend on it
+  // if timestep didn't change, just return
+  // else reset update->dt and other classes that depend on it
   // rRESPA, pair style, fixes
 
-  laststep = update->ntimestep;
   if (dt == update->dt) return;
 
+  t_elapsed = t_laststep += (update->ntimestep-laststep)*update->dt;
+  laststep = update->ntimestep;
+
   update->dt = dt;
   if (respaflag) update->integrate->reset_dt();
   if (force->pair) force->pair->reset_dt();
@@ -196,5 +207,6 @@ double FixDtReset::compute_scalar()
 
 double FixDtReset::compute_vector(int n)
 {
-  return t_elapsed;
+  if (n == 0) return t_elapsed;
+  return (double) laststep;
 }
diff --git a/src/fix_dt_reset.h b/src/fix_dt_reset.h
index 956d35d1b4..3a0146c91d 100644
--- a/src/fix_dt_reset.h
+++ b/src/fix_dt_reset.h
@@ -31,6 +31,7 @@ class FixDtReset : public Fix {
   int setmask();
   void init();
   void setup(int);
+  void initial_integrate(int);
   void end_of_step();
   double compute_scalar();
   double compute_vector(int);
@@ -40,7 +41,7 @@ class FixDtReset : public Fix {
   int minbound,maxbound;
   double tmin,tmax,xmax;
   double ftm2v;
-  double t_elapsed;
+  double dt,t_elapsed,t_laststep;
   int respaflag;
 };