diff --git a/src/compute_global_atom.cpp b/src/compute_global_atom.cpp
index d9919b13b2..37c2e038fa 100644
--- a/src/compute_global_atom.cpp
+++ b/src/compute_global_atom.cpp
@@ -13,6 +13,7 @@
 
 #include "compute_global_atom.h"
 
+#include "arg_info.h"
 #include "atom.h"
 #include "error.h"
 #include "fix.h"
@@ -22,11 +23,8 @@
 #include "update.h"
 #include "variable.h"
 
-#include <cstring>
-
 using namespace LAMMPS_NS;
 
-enum{COMPUTE,FIX,VARIABLE};
 enum{VECTOR,ARRAY};
 
 #define INVOKED_VECTOR 2
@@ -49,31 +47,15 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
   // process index arg
 
   int iarg = 3;
+  ArgInfo argi(arg[iarg]);
 
-  if (strncmp(arg[iarg],"c_",2) == 0 ||
-      strncmp(arg[iarg],"f_",2) == 0 ||
-      strncmp(arg[iarg],"v_",2) == 0) {
-    if (arg[iarg][0] == 'c') whichref = COMPUTE;
-    else if (arg[iarg][0] == 'f') whichref = FIX;
-    else if (arg[iarg][0] == 'v') whichref = VARIABLE;
+  whichref = argi.get_type();
+  indexref = argi.get_index1();
+  idref = argi.copy_name();
 
-    int n = strlen(arg[iarg]);
-    char *suffix = new char[n];
-    strcpy(suffix,&arg[iarg][2]);
-
-    char *ptr = strchr(suffix,'[');
-    if (ptr) {
-      if (suffix[strlen(suffix)-1] != ']')
-        error->all(FLERR,"Illegal compute global/atom command");
-      indexref = atoi(ptr+1);
-      *ptr = '\0';
-    } else indexref = 0;
-
-    n = strlen(suffix) + 1;
-    idref = new char[n];
-    strcpy(idref,suffix);
-    delete [] suffix;
-  } else error->all(FLERR,"Illegal compute global/atom command");
+  if ((whichref == ArgInfo::UNKNOWN) || (which[nvalues] == ArgInfo::NONE)
+      || (argi.get_dim() > 1))
+    error->all(FLERR,"Illegal compute global/atom command");
 
   iarg++;
 
@@ -94,37 +76,18 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
   value2index = new int[nargnew];
   nvalues = 0;
 
-  iarg = 0;
-  while (iarg < nargnew) {
-    ids[nvalues] = nullptr;
-    if (strncmp(arg[iarg],"c_",2) == 0 ||
-        strncmp(arg[iarg],"f_",2) == 0 ||
-        strncmp(arg[iarg],"v_",2) == 0) {
-      if (arg[iarg][0] == 'c') which[nvalues] = COMPUTE;
-      else if (arg[iarg][0] == 'f') which[nvalues] = FIX;
-      else if (arg[iarg][0] == 'v') which[nvalues] = VARIABLE;
+  for (iarg = 0; iarg < nargnew; iarg++) {
+    ArgInfo argi(arg[iarg]);
 
-      int n = strlen(arg[iarg]);
-      char *suffix = new char[n];
-      strcpy(suffix,&arg[iarg][2]);
+    which[nvalues] = argi.get_type();
+    argindex[nvalues] = argi.get_index1();
+    ids[nvalues] = argi.copy_name();
 
-      char *ptr = strchr(suffix,'[');
-      if (ptr) {
-        if (suffix[strlen(suffix)-1] != ']')
-          error->all(FLERR,"Illegal compute global/atom command");
-        argindex[nvalues] = atoi(ptr+1);
-        *ptr = '\0';
-      } else argindex[nvalues] = 0;
+    if ((which[nvalues] == ArgInfo::UNKNOWN) || (which[nvalues] == ArgInfo::NONE)
+        || (argi.get_dim() > 1))
+      error->all(FLERR,"Illegal compute slice command");
 
-      n = strlen(suffix) + 1;
-      ids[nvalues] = new char[n];
-      strcpy(ids[nvalues],suffix);
-      nvalues++;
-      delete [] suffix;
-
-    } else error->all(FLERR,"Illegal compute global/atom command");
-
-    iarg++;
+    nvalues++;
   }
 
   // if wildcard expansion occurred, free earg memory from expand_args()
@@ -136,7 +99,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
 
   // setup and error check both index arg and values
 
-  if (whichref == COMPUTE) {
+  if (whichref == ArgInfo::COMPUTE) {
     int icompute = modify->find_compute(idref);
     if (icompute < 0)
       error->all(FLERR,"Compute ID for compute global/atom does not exist");
@@ -155,7 +118,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
       error->all(FLERR,
                  "Compute global/atom compute array is accessed out-of-range");
 
-  } else if (whichref == FIX) {
+  } else if (whichref == ArgInfo::FIX) {
     int ifix = modify->find_fix(idref);
     if (ifix < 0)
       error->all(FLERR,"Fix ID for compute global/atom does not exist");
@@ -173,7 +136,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
       error->all(FLERR,
                  "Compute global/atom fix array is accessed out-of-range");
 
-  } else if (whichref == VARIABLE) {
+  } else if (whichref == ArgInfo::VARIABLE) {
     int ivariable = input->variable->find(idref);
     if (ivariable < 0)
       error->all(FLERR,"Variable name for compute global/atom does not exist");
@@ -183,7 +146,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
   }
 
   for (int i = 0; i < nvalues; i++) {
-    if (which[i] == COMPUTE) {
+    if (which[i] == ArgInfo::COMPUTE) {
       int icompute = modify->find_compute(ids[i]);
       if (icompute < 0)
         error->all(FLERR,"Compute ID for compute global/atom does not exist");
@@ -200,7 +163,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
                      "accessed out-of-range");
       }
 
-    } else if (which[i] == FIX) {
+    } else if (which[i] == ArgInfo::FIX) {
       int ifix = modify->find_fix(ids[i]);
       if (ifix < 0)
         error->all(FLERR,"Fix ID for compute global/atom does not exist");
@@ -217,7 +180,7 @@ ComputeGlobalAtom::ComputeGlobalAtom(LAMMPS *lmp, int narg, char **arg) :
                      "accessed out-of-range");
       }
 
-    } else if (which[i] == VARIABLE) {
+    } else if (which[i] == ArgInfo::VARIABLE) {
       int ivariable = input->variable->find(ids[i]);
       if (ivariable < 0)
         error->all(FLERR,"Variable name for compute global/atom "
@@ -263,17 +226,17 @@ void ComputeGlobalAtom::init()
 {
   // set indices of all computes,fixes,variables
 
-  if (whichref == COMPUTE) {
+  if (whichref == ArgInfo::COMPUTE) {
     int icompute = modify->find_compute(idref);
     if (icompute < 0)
       error->all(FLERR,"Compute ID for compute global/atom does not exist");
     ref2index = icompute;
-  } else if (whichref == FIX) {
+  } else if (whichref == ArgInfo::FIX) {
     int ifix = modify->find_fix(idref);
     if (ifix < 0)
       error->all(FLERR,"Fix ID for compute global/atom does not exist");
     ref2index = ifix;
-  } else if (whichref == VARIABLE) {
+  } else if (whichref == ArgInfo::VARIABLE) {
     int ivariable = input->variable->find(idref);
     if (ivariable < 0)
       error->all(FLERR,"Variable name for compute global/atom does not exist");
@@ -281,19 +244,19 @@ void ComputeGlobalAtom::init()
   }
 
   for (int m = 0; m < nvalues; m++) {
-    if (which[m] == COMPUTE) {
+    if (which[m] == ArgInfo::COMPUTE) {
       int icompute = modify->find_compute(ids[m]);
       if (icompute < 0)
         error->all(FLERR,"Compute ID for compute global/atom does not exist");
       value2index[m] = icompute;
 
-    } else if (which[m] == FIX) {
+    } else if (which[m] == ArgInfo::FIX) {
       int ifix = modify->find_fix(ids[m]);
       if (ifix < 0)
         error->all(FLERR,"Fix ID for compute global/atom does not exist");
       value2index[m] = ifix;
 
-    } else if (which[m] == VARIABLE) {
+    } else if (which[m] == ArgInfo::VARIABLE) {
       int ivariable = input->variable->find(ids[m]);
       if (ivariable < 0)
         error->all(FLERR,"Variable name for compute global/atom "
@@ -317,7 +280,7 @@ void ComputeGlobalAtom::compute_peratom()
     nmax = atom->nmax;
     memory->destroy(indices);
     memory->create(indices,nmax,"global/atom:indices");
-    if (whichref == VARIABLE) {
+    if (whichref == ArgInfo::VARIABLE) {
       memory->destroy(varatom);
       memory->create(varatom,nmax,"global/atom:varatom");
     }
@@ -337,7 +300,7 @@ void ComputeGlobalAtom::compute_peratom()
   int *mask = atom->mask;
   int nlocal = atom->nlocal;
 
-  if (whichref == COMPUTE) {
+  if (whichref == ArgInfo::COMPUTE) {
     Compute *compute = modify->compute[ref2index];
 
     if (!(compute->invoked_flag & INVOKED_PERATOM)) {
@@ -358,7 +321,7 @@ void ComputeGlobalAtom::compute_peratom()
           indices[i] = static_cast<int> (compute_array[i][im1]) - 1;
     }
 
-  } else if (whichref == FIX) {
+  } else if (whichref == ArgInfo::FIX) {
     if (update->ntimestep % modify->fix[ref2index]->peratom_freq)
       error->all(FLERR,"Fix used in compute global/atom not "
                  "computed at compatible time");
@@ -377,7 +340,7 @@ void ComputeGlobalAtom::compute_peratom()
           indices[i] = static_cast<int> (fix_array[i][im1]) - 1;
     }
 
-  } else if (whichref == VARIABLE) {
+  } else if (whichref == ArgInfo::VARIABLE) {
     input->variable->compute_atom(ref2index,igroup,varatom,1,0);
     for (i = 0; i < nlocal; i++)
       if (mask[i] & groupbit)
@@ -394,7 +357,7 @@ void ComputeGlobalAtom::compute_peratom()
       int vmax;
       double *source;
 
-      if (which[m] == COMPUTE) {
+      if (which[m] == ArgInfo::COMPUTE) {
         Compute *compute = modify->compute[value2index[m]];
 
         if (!(compute->invoked_flag & INVOKED_VECTOR)) {
@@ -405,7 +368,7 @@ void ComputeGlobalAtom::compute_peratom()
         source = compute->vector;
         vmax = compute->size_vector;
 
-      } else if (which[m] == FIX) {
+      } else if (which[m] == ArgInfo::FIX) {
         if (update->ntimestep % modify->fix[value2index[m]]->peratom_freq)
           error->all(FLERR,"Fix used in compute global/atom not "
                      "computed at compatible time");
@@ -423,7 +386,7 @@ void ComputeGlobalAtom::compute_peratom()
 
         source = vecglobal;
 
-      } else if (which[m] == VARIABLE) {
+      } else if (which[m] == ArgInfo::VARIABLE) {
         vmax = input->variable->compute_vector(value2index[m],&source);
       }
 
@@ -452,7 +415,7 @@ void ComputeGlobalAtom::compute_peratom()
       double *source;
       int col = argindex[m] - 1;
 
-      if (which[m] == COMPUTE) {
+      if (which[m] == ArgInfo::COMPUTE) {
         Compute *compute = modify->compute[value2index[m]];
 
         if (!(compute->invoked_flag & INVOKED_ARRAY)) {
@@ -474,7 +437,7 @@ void ComputeGlobalAtom::compute_peratom()
 
         source = vecglobal;
 
-      } else if (which[m] == FIX) {
+      } else if (which[m] == ArgInfo::FIX) {
         if (update->ntimestep % modify->fix[value2index[m]]->peratom_freq)
           error->all(FLERR,"Fix used in compute global/atom not "
                      "computed at compatible time");
@@ -492,7 +455,7 @@ void ComputeGlobalAtom::compute_peratom()
 
         source = vecglobal;
 
-      } else if (which[m] == VARIABLE) {
+      } else if (which[m] == ArgInfo::VARIABLE) {
         vmax = input->variable->compute_vector(value2index[m],&source);
       }