diff --git a/src/pair_zero.cpp b/src/pair_zero.cpp
index 5c229d6b71..83505edd35 100644
--- a/src/pair_zero.cpp
+++ b/src/pair_zero.cpp
@@ -1,4 +1,3 @@
-// clang-format off
 /* ----------------------------------------------------------------------
    LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
    https://www.lammps.org/, Sandia National Laboratories
@@ -20,8 +19,8 @@
 
 #include "atom.h"
 #include "comm.h"
-#include "memory.h"
 #include "error.h"
+#include "memory.h"
 
 #include <cstring>
 
@@ -29,11 +28,12 @@ using namespace LAMMPS_NS;
 
 /* ---------------------------------------------------------------------- */
 
-PairZero::PairZero(LAMMPS *lmp) : Pair(lmp) {
-  coeffflag=1;
-  writedata=1;
-  single_enable=1;
-  respa_enable=1;
+PairZero::PairZero(LAMMPS *lmp) : Pair(lmp)
+{
+  coeffflag = 1;
+  writedata = 1;
+  single_enable = 1;
+  respa_enable = 1;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -51,15 +51,15 @@ PairZero::~PairZero()
 
 void PairZero::compute(int eflag, int vflag)
 {
- ev_init(eflag,vflag);
- if (vflag_fdotr) virial_fdotr_compute();
+  ev_init(eflag, vflag);
+  if (vflag_fdotr) virial_fdotr_compute();
 }
 
 /* ---------------------------------------------------------------------- */
 
 void PairZero::compute_outer(int eflag, int vflag)
 {
- ev_init(eflag,vflag);
+  ev_init(eflag, vflag);
 }
 
 /* ----------------------------------------------------------------------
@@ -69,15 +69,14 @@ void PairZero::compute_outer(int eflag, int vflag)
 void PairZero::allocate()
 {
   allocated = 1;
-  int n = atom->ntypes;
+  int np1 = atom->ntypes + 1;
 
-  memory->create(setflag,n+1,n+1,"pair:setflag");
-  for (int i = 1; i <= n; i++)
-    for (int j = i; j <= n; j++)
-      setflag[i][j] = 0;
+  memory->create(setflag, np1, np1, "pair:setflag");
+  for (int i = 1; i < np1; i++)
+    for (int j = i; j < np1; j++) setflag[i][j] = 0;
 
-  memory->create(cutsq,n+1,n+1,"pair:cutsq");
-  memory->create(cut,n+1,n+1,"pair:cut");
+  memory->create(cutsq, np1, np1, "pair:cutsq");
+  memory->create(cut, np1, np1, "pair:cut");
 }
 
 /* ----------------------------------------------------------------------
@@ -86,22 +85,22 @@ void PairZero::allocate()
 
 void PairZero::settings(int narg, char **arg)
 {
-  if ((narg != 1) && (narg != 2))
-    error->all(FLERR,"Illegal pair_style command");
+  if ((narg != 1) && (narg != 2)) error->all(FLERR, "Illegal pair_style command");
 
-  cut_global = utils::numeric(FLERR,arg[0],false,lmp);
+  cut_global = utils::numeric(FLERR, arg[0], false, lmp);
   if (narg == 2) {
-    if (strcmp("nocoeff",arg[1]) == 0) coeffflag=0;
-    else error->all(FLERR,"Illegal pair_style command");
+    if (strcmp("nocoeff", arg[1]) == 0)
+      coeffflag = 0;
+    else
+      error->all(FLERR, "Illegal pair_style command");
   }
 
   // reset cutoffs that have been explicitly set
 
   if (allocated) {
-    int i,j;
+    int i, j;
     for (i = 1; i <= atom->ntypes; i++)
-      for (j = i+1; j <= atom->ntypes; j++)
-        cut[i][j] = cut_global;
+      for (j = i + 1; j <= atom->ntypes; j++) cut[i][j] = cut_global;
   }
 }
 
@@ -112,27 +111,27 @@ void PairZero::settings(int narg, char **arg)
 void PairZero::coeff(int narg, char **arg)
 {
   if ((narg < 2) || (coeffflag && narg > 3))
-    error->all(FLERR,"Incorrect args for pair coefficients");
+    error->all(FLERR, "Incorrect args for pair coefficients");
 
   if (!allocated) allocate();
 
-  int ilo,ihi,jlo,jhi;
-  utils::bounds(FLERR,arg[0],1,atom->ntypes,ilo,ihi,error);
-  utils::bounds(FLERR,arg[1],1,atom->ntypes,jlo,jhi,error);
+  int ilo, ihi, jlo, jhi;
+  utils::bounds(FLERR, arg[0], 1, atom->ntypes, ilo, ihi, error);
+  utils::bounds(FLERR, arg[1], 1, atom->ntypes, jlo, jhi, error);
 
   double cut_one = cut_global;
-  if (coeffflag && (narg == 3)) cut_one = utils::numeric(FLERR,arg[2],false,lmp);
+  if (coeffflag && (narg == 3)) cut_one = utils::numeric(FLERR, arg[2], false, lmp);
 
   int count = 0;
   for (int i = ilo; i <= ihi; i++) {
-    for (int j = MAX(jlo,i); j <= jhi; j++) {
+    for (int j = MAX(jlo, i); j <= jhi; j++) {
       cut[i][j] = cut_one;
       setflag[i][j] = 1;
       count++;
     }
   }
 
-  if (count == 0) error->all(FLERR,"Incorrect args for pair coefficients");
+  if (count == 0) error->all(FLERR, "Incorrect args for pair coefficients");
 }
 
 /* ----------------------------------------------------------------------
@@ -141,9 +140,7 @@ void PairZero::coeff(int narg, char **arg)
 
 double PairZero::init_one(int i, int j)
 {
-  if (setflag[i][j] == 0) {
-    cut[i][j] = mix_distance(cut[i][i],cut[j][j]);
-  }
+  if (setflag[i][j] == 0) { cut[i][j] = mix_distance(cut[i][i], cut[j][j]); }
 
   return cut[i][j];
 }
@@ -156,13 +153,11 @@ void PairZero::write_restart(FILE *fp)
 {
   write_restart_settings(fp);
 
-  int i,j;
+  int i, j;
   for (i = 1; i <= atom->ntypes; i++)
     for (j = i; j <= atom->ntypes; j++) {
-      fwrite(&setflag[i][j],sizeof(int),1,fp);
-      if (setflag[i][j]) {
-        fwrite(&cut[i][j],sizeof(double),1,fp);
-      }
+      fwrite(&setflag[i][j], sizeof(int), 1, fp);
+      if (setflag[i][j]) { fwrite(&cut[i][j], sizeof(double), 1, fp); }
     }
 }
 
@@ -175,17 +170,15 @@ void PairZero::read_restart(FILE *fp)
   read_restart_settings(fp);
   allocate();
 
-  int i,j;
+  int i, j;
   int me = comm->me;
   for (i = 1; i <= atom->ntypes; i++)
     for (j = i; j <= atom->ntypes; j++) {
-      if (me == 0) utils::sfread(FLERR,&setflag[i][j],sizeof(int),1,fp,nullptr,error);
-      MPI_Bcast(&setflag[i][j],1,MPI_INT,0,world);
+      if (me == 0) utils::sfread(FLERR, &setflag[i][j], sizeof(int), 1, fp, nullptr, error);
+      MPI_Bcast(&setflag[i][j], 1, MPI_INT, 0, world);
       if (setflag[i][j]) {
-        if (me == 0) {
-          utils::sfread(FLERR,&cut[i][j],sizeof(double),1,fp,nullptr,error);
-        }
-        MPI_Bcast(&cut[i][j],1,MPI_DOUBLE,0,world);
+        if (me == 0) { utils::sfread(FLERR, &cut[i][j], sizeof(double), 1, fp, nullptr, error); }
+        MPI_Bcast(&cut[i][j], 1, MPI_DOUBLE, 0, world);
       }
     }
 }
@@ -196,8 +189,8 @@ void PairZero::read_restart(FILE *fp)
 
 void PairZero::write_restart_settings(FILE *fp)
 {
-  fwrite(&cut_global,sizeof(double),1,fp);
-  fwrite(&coeffflag,sizeof(int),1,fp);
+  fwrite(&cut_global, sizeof(double), 1, fp);
+  fwrite(&coeffflag, sizeof(int), 1, fp);
 }
 
 /* ----------------------------------------------------------------------
@@ -208,11 +201,11 @@ void PairZero::read_restart_settings(FILE *fp)
 {
   int me = comm->me;
   if (me == 0) {
-    utils::sfread(FLERR,&cut_global,sizeof(double),1,fp,nullptr,error);
-    utils::sfread(FLERR,&coeffflag,sizeof(int),1,fp,nullptr,error);
+    utils::sfread(FLERR, &cut_global, sizeof(double), 1, fp, nullptr, error);
+    utils::sfread(FLERR, &coeffflag, sizeof(int), 1, fp, nullptr, error);
   }
-  MPI_Bcast(&cut_global,1,MPI_DOUBLE,0,world);
-  MPI_Bcast(&coeffflag,1,MPI_INT,0,world);
+  MPI_Bcast(&cut_global, 1, MPI_DOUBLE, 0, world);
+  MPI_Bcast(&coeffflag, 1, MPI_INT, 0, world);
 }
 
 /* ----------------------------------------------------------------------
@@ -221,8 +214,7 @@ void PairZero::read_restart_settings(FILE *fp)
 
 void PairZero::write_data(FILE *fp)
 {
-  for (int i = 1; i <= atom->ntypes; i++)
-    fprintf(fp,"%d\n",i);
+  for (int i = 1; i <= atom->ntypes; i++) fprintf(fp, "%d\n", i);
 }
 
 /* ----------------------------------------------------------------------
@@ -232,17 +224,14 @@ void PairZero::write_data(FILE *fp)
 void PairZero::write_data_all(FILE *fp)
 {
   for (int i = 1; i <= atom->ntypes; i++)
-    for (int j = i; j <= atom->ntypes; j++)
-      fprintf(fp,"%d %d %g\n",i,j,cut[i][j]);
+    for (int j = i; j <= atom->ntypes; j++) fprintf(fp, "%d %d %g\n", i, j, cut[i][j]);
 }
 
 /* ---------------------------------------------------------------------- */
 
-double PairZero::single(int /*i*/, int /*j*/, int /* itype */, int /* jtype */,
-                        double /* rsq */, double /*factor_coul*/,
-                        double /* factor_lj */, double &fforce)
+double PairZero::single(int /*i*/, int /*j*/, int /* itype */, int /* jtype */, double /* rsq */,
+                        double /*factor_coul*/, double /* factor_lj */, double &fforce)
 {
   fforce = 0.0;
   return 0.0;
 }
-