diff --git a/src/fix_temp_csvr.cpp b/src/fix_temp_csvr.cpp
new file mode 100644
index 0000000000..c540e675ce
--- /dev/null
+++ b/src/fix_temp_csvr.cpp
@@ -0,0 +1,302 @@
+/* ----------------------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+/* ----------------------------------------------------------------------
+   Contributing author: Axel Kohlmeyer (ICTP, Italy)
+------------------------------------------------------------------------- */
+
+#include "string.h"
+#include "stdlib.h"
+#include "math.h"
+#include "fix_temp_csvr.h"
+#include "atom.h"
+#include "force.h"
+#include "comm.h"
+#include "input.h"
+#include "variable.h"
+#include "group.h"
+#include "update.h"
+#include "modify.h"
+#include "compute.h"
+#include "random_mars.h"
+#include "error.h"
+
+using namespace LAMMPS_NS;
+using namespace FixConst;
+
+enum{NOBIAS,BIAS};
+enum{CONSTANT,EQUAL};
+
+/* ---------------------------------------------------------------------- */
+
+FixTempCSVR::FixTempCSVR(LAMMPS *lmp, int narg, char **arg) :
+  Fix(lmp, narg, arg)
+{
+  if (narg != 7) error->all(FLERR,"Illegal fix temp/csvr command");
+
+  // CSVR thermostat should be applied every step
+
+  nevery = 1;
+  scalar_flag = 1;
+  global_freq = nevery;
+  extscalar = 1;
+
+  tstr = NULL;
+  if (strstr(arg[3],"v_") == arg[3]) {
+    int n = strlen(&arg[3][2]) + 1;
+    tstr = new char[n];
+    strcpy(tstr,&arg[3][2]);
+    tstyle = EQUAL;
+  } else {
+    t_start = force->numeric(FLERR,arg[3]);
+    t_target = t_start;
+    tstyle = CONSTANT;
+  }
+
+  t_stop = force->numeric(FLERR,arg[4]);
+  t_period = force->numeric(FLERR,arg[5]);
+  int seed = force->inumeric(FLERR,arg[6]);
+
+  // error checks
+
+  if (t_period <= 0.0) error->all(FLERR,"Fix temp/csvr period must be > 0.0");
+  if (seed <= 0) error->all(FLERR,"Illegal fix temp/csvr random seed");
+
+  // create a new compute temp style
+  // id = fix-ID + temp, compute group = fix group
+
+  int n = strlen(id) + 6;
+  id_temp = new char[n];
+  strcpy(id_temp,id);
+  strcat(id_temp,"_temp");
+
+  char **newarg = new char*[3];
+  newarg[0] = id_temp;
+  newarg[1] = group->names[igroup];
+  newarg[2] = (char *) "temp";
+  modify->add_compute(3,newarg);
+  delete [] newarg;
+  tflag = 1;
+
+  random = new RanMars(lmp,seed + comm->me);
+
+  energy = 0.0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+FixTempCSVR::~FixTempCSVR()
+{
+  delete [] tstr;
+
+  // delete temperature if fix created it
+
+  if (tflag) modify->delete_compute(id_temp);
+  delete [] id_temp;
+
+  delete random;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int FixTempCSVR::setmask()
+{
+  int mask = 0;
+  mask |= END_OF_STEP;
+  mask |= THERMO_ENERGY;
+  return mask;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void FixTempCSVR::init()
+{
+  // check variable
+
+  if (tstr) {
+    tvar = input->variable->find(tstr);
+    if (tvar < 0)
+      error->all(FLERR,"Variable name for fix temp/csvr does not exist");
+    if (input->variable->equalstyle(tvar)) tstyle = EQUAL;
+    else error->all(FLERR,"Variable for fix temp/csvr is invalid style");
+  }
+
+  int icompute = modify->find_compute(id_temp);
+  if (icompute < 0)
+    error->all(FLERR,"Temperature ID for fix temp/csvr does not exist");
+  temperature = modify->compute[icompute];
+
+  if (temperature->tempbias) which = BIAS;
+  else which = NOBIAS;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void FixTempCSVR::end_of_step()
+{
+  double t_current = temperature->compute_scalar();
+
+  double delta = update->ntimestep - update->beginstep;
+  if (delta != 0.0) delta /= update->endstep - update->beginstep;
+
+  // set current t_target
+  // if variable temp, evaluate variable, wrap with clear/add
+
+  if (tstyle == CONSTANT)
+    t_target = t_start + delta * (t_stop-t_start);
+  else {
+    modify->clearstep_compute();
+    t_target = input->variable->compute_equal(tvar);
+    if (t_target < 0.0)
+      error->one(FLERR,
+                 "Fix temp/csvr variable returned negative temperature");
+    modify->addstep_compute(update->ntimestep + nevery);
+  }
+
+  // Langevin thermostat, implemented as decribed in
+  // Bussi and Parrinello, Phys. Rev. E (2007).
+  // it is a linear combination of old velocities and new,
+  // randomly chosen, velocity, with proper coefficients
+
+  double **v = atom->v;
+  int *mask = atom->mask;
+  int nlocal = atom->nlocal;
+  const double c1 = exp(-update->dt/t_period);
+
+  if (atom->rmass_flag) { // per atom masses
+    const double * const rmass = atom->rmass;
+  
+    if (which == NOBIAS) {
+      for (int i = 0; i < nlocal; i++) {
+        if (mask[i] & groupbit) {
+          const double m = rmass[i];
+          const double c2 = sqrt((1.0-c1*c1)*t_target/m);
+          for (int j = 0; j < 3; ++j) {
+            energy  += 0.5*m*v[i][j]*v[i][j];
+            v[i][j] *= c1;
+            v[i][j] += c2*random->gaussian();
+            energy  -= 0.5*m*v[i][j]*v[i][j];
+          }
+        }
+      }
+    } else {
+      for (int i = 0; i < nlocal; i++) {
+        if (mask[i] & groupbit) {
+          const double m = rmass[i];
+          const double c2 = sqrt((1.0-c1*c1)*t_target/m);
+          temperature->remove_bias(i,v[i]);
+          for (int j = 0; j < 3; ++j) {
+            energy  += 0.5*rmass[i]*v[i][j]*v[i][j];
+            v[i][j] *= c1;
+            v[i][j] += c2*random->gaussian();
+            energy  -= 0.5*rmass[i]*v[i][j]*v[i][j];
+          }
+          temperature->restore_bias(i,v[i]);
+        }
+      }
+    }
+  } else { // per atom type masses
+
+    const double * const mass = atom->mass;
+    const int    * const type = atom->type;
+
+    if (which == NOBIAS) {
+      for (int i = 0; i < nlocal; i++) {
+        if (mask[i] & groupbit) {
+          const double m = mass[type[i]];
+          const double c2 = sqrt((1.0-c1*c1)*t_target/m);
+
+          for (int j = 0; j < 3; ++j) {
+            energy  += 0.5*m*v[i][j]*v[i][j];
+            v[i][j] *= c1;
+            v[i][j] += c2*random->gaussian();
+            energy  -= 0.5*m*v[i][j]*v[i][j];
+          }
+        }
+      }
+    } else {
+      for (int i = 0; i < nlocal; i++) {
+        if (mask[i] & groupbit) {
+          const double m = mass[type[i]];
+          const double c2 = sqrt((1.0-c1*c1)*t_target/m);
+
+          temperature->remove_bias(i,v[i]);
+          for (int j = 0; j < 3; ++j) {
+            energy  += 0.5*m*v[i][j]*v[i][j];
+            v[i][j] *= c1;
+            v[i][j] += c2*random->gaussian();
+            energy  -= 0.5*m*v[i][j]*v[i][j];
+          }
+          temperature->restore_bias(i,v[i]);
+        }
+      }
+    }
+  }
+}
+
+/* ---------------------------------------------------------------------- */
+
+int FixTempCSVR::modify_param(int narg, char **arg)
+{
+  if (strcmp(arg[0],"temp") == 0) {
+    if (narg < 2) error->all(FLERR,"Illegal fix_modify command");
+    if (tflag) {
+      modify->delete_compute(id_temp);
+      tflag = 0;
+    }
+    delete [] id_temp;
+    int n = strlen(arg[1]) + 1;
+    id_temp = new char[n];
+    strcpy(id_temp,arg[1]);
+
+    int icompute = modify->find_compute(id_temp);
+    if (icompute < 0)
+      error->all(FLERR,"Could not find fix_modify temperature ID");
+    temperature = modify->compute[icompute];
+
+    if (temperature->tempflag == 0)
+      error->all(FLERR,
+                 "Fix_modify temperature ID does not compute temperature");
+    if (temperature->igroup != igroup && comm->me == 0)
+      error->warning(FLERR,"Group for fix_modify temp != fix group");
+    return 2;
+  }
+  return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void FixTempCSVR::reset_target(double t_new)
+{
+  t_target = t_start = t_stop = t_new;
+}
+
+/* ---------------------------------------------------------------------- */
+
+double FixTempCSVR::compute_scalar()
+{
+  return energy;
+}
+
+/* ----------------------------------------------------------------------
+   extract thermostat properties
+------------------------------------------------------------------------- */
+
+void *FixTempCSVR::extract(const char *str, int &dim)
+{
+  dim=0;
+  if (strcmp(str,"t_target") == 0) {
+    return &t_target;
+  }
+  return NULL;
+}
diff --git a/src/fix_temp_csvr.h b/src/fix_temp_csvr.h
new file mode 100644
index 0000000000..601b032af6
--- /dev/null
+++ b/src/fix_temp_csvr.h
@@ -0,0 +1,104 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#ifdef FIX_CLASS
+
+FixStyle(temp/csvr,FixTempCSVR)
+
+#else
+
+#ifndef LMP_FIX_TEMP_CSVR_H
+#define LMP_FIX_TEMP_CSVR_H
+
+#include "fix.h"
+
+namespace LAMMPS_NS {
+
+class FixTempCSVR : public Fix {
+ public:
+  FixTempCSVR(class LAMMPS *, int, char **);
+  ~FixTempCSVR();
+  int setmask();
+  void init();
+  void end_of_step();
+  int modify_param(int, char **);
+  void reset_target(double);
+  double compute_scalar();
+  virtual void *extract(const char *, int &);
+
+ private:
+  int which;
+  double t_start,t_stop,t_period,t_target;
+  double energy;
+  int tstyle,tvar;
+  char *tstr;
+
+  char *id_temp;
+  class Compute *temperature;
+  int tflag;
+
+  class RanMars *random;
+};
+
+}
+
+#endif
+#endif
+
+/* ERROR/WARNING messages:
+
+E: Illegal ... command
+
+Self-explanatory.  Check the input script syntax and compare to the
+documentation for the command.  You can use -echo screen as a
+command-line option when running LAMMPS to see the offending line.
+
+E: Fix temp/csvr period must be > 0.0
+
+Self-explanatory.
+
+E: Variable name for fix temp/csvr does not exist
+
+Self-explanatory.
+
+E: Variable for fix temp/csvr is invalid style
+
+Only equal-style variables can be used.
+
+E: Temperature ID for fix temp/csvr does not exist
+
+Self-explanatory.
+
+E: Computed temperature for fix temp/csvr cannot be 0.0
+
+Self-explanatory.
+
+E: Fix temp/csvr variable returned negative temperature
+
+Self-explanatory.
+
+E: Could not find fix_modify temperature ID
+
+The compute ID for computing temperature does not exist.
+
+E: Fix_modify temperature ID does not compute temperature
+
+The compute ID assigned to the fix must compute temperature.
+
+W: Group for fix_modify temp != fix group
+
+The fix_modify command is specifying a temperature computation that
+computes a temperature on a different group of atoms than the fix
+itself operates on.  This is probably not what you want to do.
+
+*/