diff --git a/src/compute_pair.cpp b/src/compute_pair.cpp
index 951df069ee..9617e016aa 100644
--- a/src/compute_pair.cpp
+++ b/src/compute_pair.cpp
@@ -21,34 +21,42 @@
 
 using namespace LAMMPS_NS;
 
+enum{EPAIR,EVDWL,ECOUL};
+
 /* ---------------------------------------------------------------------- */
 
 ComputePair::ComputePair(LAMMPS *lmp, int narg, char **arg) : 
   Compute(lmp, narg, arg)
 {
-  if (narg != 4) error->all("Illegal compute pair command");
+  if (narg < 4 || narg > 5) error->all("Illegal compute pair command");
   if (igroup) error->all("Compute pair must use group all");
 
+  scalar_flag = 1;
+  extscalar = 1;
+  peflag = 1;
+  timeflag = 1;
+
   int n = strlen(arg[3]) + 1;
   pstyle = new char[n];
   strcpy(pstyle,arg[3]);
 
+  if (narg == 5) {
+    if (strcmp(arg[4],"epair") == 0) evalue = EPAIR;
+    if (strcmp(arg[4],"evdwl") == 0) evalue = EVDWL;
+    if (strcmp(arg[4],"ecoul") == 0) evalue = ECOUL;
+  } else evalue = EPAIR;
+
   pair = force->pair_match(pstyle,1);
   if (!pair) error->all("Unrecognized pair style in compute pair command");
   npair = pair->nextra;
-  if (!npair) 
-    error->all("Pair style in compute pair command stores no values");
 
-  // settings
-
-  vector_flag = 1;
-  size_vector = npair;
-  extvector = 1;
-  peflag = 1;
-  timeflag = 1;
-
-  one = new double[npair];
-  vector = new double[npair];
+  if (npair) {
+    vector_flag = 1;
+    size_vector = npair;
+    extvector = 1;
+    one = new double[npair];
+    vector = new double[npair];
+  } else one = vector = NULL;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -72,6 +80,23 @@ void ComputePair::init()
 
 /* ---------------------------------------------------------------------- */
 
+double ComputePair::compute_scalar()
+{
+  invoked_scalar = update->ntimestep;
+  if (update->eflag_global != invoked_scalar)
+    error->all("Energy was not tallied on needed timestep");
+
+  double eng;
+  if (evalue == EPAIR) eng = pair->eng_vdwl + pair->eng_coul;
+  else if (evalue == EVDWL) eng = pair->eng_vdwl;
+  else if (evalue == ECOUL) eng = pair->eng_coul;
+
+  MPI_Allreduce(&eng,&scalar,1,MPI_DOUBLE,MPI_SUM,world);
+  return scalar;
+}
+
+/* ---------------------------------------------------------------------- */
+
 void ComputePair::compute_vector()
 {
   invoked_vector = update->ntimestep;
diff --git a/src/compute_pair.h b/src/compute_pair.h
index 3d7d5dccfa..cf0e955ad9 100644
--- a/src/compute_pair.h
+++ b/src/compute_pair.h
@@ -29,10 +29,11 @@ class ComputePair : public Compute {
   ComputePair(class LAMMPS *, int, char **);
   ~ComputePair();
   void init();
+  double compute_scalar();
   void compute_vector();
 
  private:
-  int npair;
+  int evalue,npair;
   char *pstyle;
   class Pair *pair;
   double *one;
diff --git a/src/pair.cpp b/src/pair.cpp
index 5091d1f62f..d48a004997 100644
--- a/src/pair.cpp
+++ b/src/pair.cpp
@@ -426,6 +426,7 @@ void Pair::ev_tally(int i, int j, int nlocal, int newton_pair,
 void Pair::ev_tally_full(int i, double evdwl, double ecoul, double fpair, 
                          double delx, double dely, double delz)
 {
+  double v[6];
 
   if (eflag_either) {
     if (eflag_global) {
@@ -436,23 +437,30 @@ void Pair::ev_tally_full(int i, double evdwl, double ecoul, double fpair,
   }
 
   if (vflag_either) {
-    if (vflag_global) {
-      virial[0] += 0.5*delx*delx*fpair;
-      virial[1] += 0.5*dely*dely*fpair;
-      virial[2] += 0.5*delz*delz*fpair;
-      virial[3] += 0.5*delx*dely*fpair;
-      virial[4] += 0.5*delx*delz*fpair;
-      virial[5] += 0.5*dely*delz*fpair;
-    }
-  }
+    v[0] = 0.5*delx*delx*fpair;
+    v[1] = 0.5*dely*dely*fpair;
+    v[2] = 0.5*delz*delz*fpair;
+    v[3] = 0.5*delx*dely*fpair;
+    v[4] = 0.5*delx*delz*fpair;
+    v[5] = 0.5*dely*delz*fpair;
 
-  if (vflag_atom) {
-    vatom[i][0] += 0.5*delx*delx*fpair;
-    vatom[i][1] += 0.5*dely*dely*fpair;
-    vatom[i][2] += 0.5*delz*delz*fpair;
-    vatom[i][3] += 0.5*delx*dely*fpair;
-    vatom[i][4] += 0.5*delx*delz*fpair;
-    vatom[i][5] += 0.5*dely*delz*fpair;
+    if (vflag_global) {
+      virial[0] += v[0];
+      virial[1] += v[1];
+      virial[2] += v[2];
+      virial[3] += v[3];
+      virial[4] += v[4];
+      virial[5] += v[5];
+    }
+
+    if (vflag_atom) {
+      vatom[i][0] += v[0];
+      vatom[i][1] += v[1];
+      vatom[i][2] += v[2];
+      vatom[i][3] += v[3];
+      vatom[i][4] += v[4];
+      vatom[i][5] += v[5];
+    }
   }
 }
 
@@ -576,36 +584,36 @@ void Pair::ev_tally_xyz_full(int i, double evdwl, double ecoul,
   }
 
   if (vflag_either) {
-    v[0] = delx*fx;
-    v[1] = dely*fy;
-    v[2] = delz*fz;
-    v[3] = delx*fy;
-    v[4] = delx*fz;
-    v[5] = dely*fz;
-  }
+    v[0] = 0.5*delx*fx;
+    v[1] = 0.5*dely*fy;
+    v[2] = 0.5*delz*fz;
+    v[3] = 0.5*delx*fy;
+    v[4] = 0.5*delx*fz;
+    v[5] = 0.5*dely*fz;
 
-  if (vflag_global) {
-    virial[0] += 0.5*v[0];
-    virial[1] += 0.5*v[1];
-    virial[2] += 0.5*v[2];
-    virial[3] += 0.5*v[3];
-    virial[4] += 0.5*v[4];
-    virial[5] += 0.5*v[5];
-  }
-
-  if (vflag_atom) {
-    vatom[i][0] += 0.5*v[0];
-    vatom[i][1] += 0.5*v[1];
-    vatom[i][2] += 0.5*v[2];
-    vatom[i][3] += 0.5*v[3];
-    vatom[i][4] += 0.5*v[4];
-    vatom[i][5] += 0.5*v[5];
+    if (vflag_global) {
+      virial[0] += v[0];
+      virial[1] += v[1];
+      virial[2] += v[2];
+      virial[3] += v[3];
+      virial[4] += v[4];
+      virial[5] += v[5];
+    }
+    
+    if (vflag_atom) {
+      vatom[i][0] += v[0];
+      vatom[i][1] += v[1];
+      vatom[i][2] += v[2];
+      vatom[i][3] += v[3];
+      vatom[i][4] += v[4];
+      vatom[i][5] += v[5];
+    }
   }
 }
 
 /* ----------------------------------------------------------------------
    tally eng_vdwl and virial into global and per-atom accumulators
-   called by SW potential, newton_pair is always on
+   called by SW and hbond potentials, newton_pair is always on
    virial = riFi + rjFj + rkFk = (rj-ri) Fj + (rk-ri) Fk = drji*fj + drki*fk
  ------------------------------------------------------------------------- */
 
@@ -627,20 +635,36 @@ void Pair::ev_tally3(int i, int j, int k, double evdwl, double ecoul,
     }
   }
 
-  if (vflag_atom) {
-    v[0] = THIRD * (drji[0]*fj[0] + drki[0]*fk[0]);
-    v[1] = THIRD * (drji[1]*fj[1] + drki[1]*fk[1]);
-    v[2] = THIRD * (drji[2]*fj[2] + drki[2]*fk[2]);
-    v[3] = THIRD * (drji[0]*fj[1] + drki[0]*fk[1]);
-    v[4] = THIRD * (drji[0]*fj[2] + drki[0]*fk[2]);
-    v[5] = THIRD * (drji[1]*fj[2] + drki[1]*fk[2]);
+  if (vflag_either) {
+    v[0] = drji[0]*fj[0] + drki[0]*fk[0];
+    v[1] = drji[1]*fj[1] + drki[1]*fk[1];
+    v[2] = drji[2]*fj[2] + drki[2]*fk[2];
+    v[3] = drji[0]*fj[1] + drki[0]*fk[1];
+    v[4] = drji[0]*fj[2] + drki[0]*fk[2];
+    v[5] = drji[1]*fj[2] + drki[1]*fk[2];
+      
+    if (vflag_global) {
+      virial[0] += v[0];
+      virial[1] += v[1];
+      virial[2] += v[2];
+      virial[3] += v[3];
+      virial[4] += v[4];
+      virial[5] += v[5];
+    }
 
-    vatom[i][0] += v[0]; vatom[i][1] += v[1]; vatom[i][2] += v[2];
-    vatom[i][3] += v[3]; vatom[i][4] += v[4]; vatom[i][5] += v[5];
-    vatom[j][0] += v[0]; vatom[j][1] += v[1]; vatom[j][2] += v[2];
-    vatom[j][3] += v[3]; vatom[j][4] += v[4]; vatom[j][5] += v[5];
-    vatom[k][0] += v[0]; vatom[k][1] += v[1]; vatom[k][2] += v[2];
-    vatom[k][3] += v[3]; vatom[k][4] += v[4]; vatom[k][5] += v[5];
+    if (vflag_atom) {
+      vatom[i][0] += THIRD*v[0]; vatom[i][1] += THIRD*v[1];
+      vatom[i][2] += THIRD*v[2]; vatom[i][3] += THIRD*v[3]; 
+      vatom[i][4] += THIRD*v[4]; vatom[i][5] += THIRD*v[5];
+
+      vatom[j][0] += THIRD*v[0]; vatom[j][1] += THIRD*v[1];
+      vatom[j][2] += THIRD*v[2]; vatom[j][3] += THIRD*v[3];
+      vatom[j][4] += THIRD*v[4]; vatom[j][5] += THIRD*v[5];
+
+      vatom[k][0] += THIRD*v[0]; vatom[k][1] += THIRD*v[1];
+      vatom[k][2] += THIRD*v[2]; vatom[k][3] += THIRD*v[3];
+      vatom[k][4] += THIRD*v[4]; vatom[k][5] += THIRD*v[5];
+    }
   }
 }