initial support for par-atom centroid virial in pair styles

src/pair.cpp

@@ -72,6 +72,7 @@ Pair::Pair(LAMMPS *lmp) : Pointers(lmp)
 
   ewaldflag = pppmflag = msmflag = dispersionflag = tip4pflag = dipoleflag = spinflag = 0;
   reinitflag = 1;
+  cntratmstressflag = 4;
 
   // pair_modify settings
 
@@ -91,9 +92,10 @@ Pair::Pair(LAMMPS *lmp) : Pointers(lmp)
   allocated = 0;
   suffix_flag = Suffix::NONE;
 
-  maxeatom = maxvatom = 0;
+  maxeatom = maxvatom = maxcvatom = 0;
   eatom = NULL;
   vatom = NULL;
+  cvatom = NULL;
 
   num_tally_compute = 0;
   list_tally_compute = NULL;
@@ -122,6 +124,7 @@ Pair::~Pair()
 
   memory->destroy(eatom);
   memory->destroy(vatom);
+  memory->destroy(cvatom);
 }
 
 /* ----------------------------------------------------------------------
@@ -779,9 +782,20 @@ void Pair::ev_setup(int eflag, int vflag, int alloc)
   eflag_global = eflag % 2;
   eflag_atom = eflag / 2;
 
-  vflag_either = vflag;
   vflag_global = vflag % 4;
-  vflag_atom = vflag / 4;
+  vflag_atom = vflag & 4;
+
+  if (vflag & 8) {
+    if (cntratmstressflag & 2) {
+      cvflag_atom = 1;
+    } else {
+      vflag_atom = 1;
+    }
+    // extra check, because both bits might be set
+    if (cntratmstressflag & 1) vflag_atom = 1;
+  }
+
+  vflag_either = vflag_global || vflag_atom;
 
   // reallocate per-atom arrays if necessary
 
@@ -799,6 +813,13 @@ void Pair::ev_setup(int eflag, int vflag, int alloc)
       memory->create(vatom,comm->nthreads*maxvatom,6,"pair:vatom");
     }
   }
+  if (cvflag_atom && atom->nmax > maxcvatom) {
+    maxcvatom = atom->nmax;
+    if (alloc) {
+      memory->destroy(cvatom);
+      memory->create(cvatom,comm->nthreads*maxcvatom,9,"pair:cvatom");
+    }
+  }
 
   // zero accumulators
   // use force->newton instead of newton_pair
@@ -823,6 +844,22 @@ void Pair::ev_setup(int eflag, int vflag, int alloc)
       vatom[i][5] = 0.0;
     }
   }
+  if (cvflag_atom && alloc) {
+    n = atom->nlocal;
+    if (force->newton) n += atom->nghost;
+    for (i = 0; i < n; i++) {
+      cvatom[i][0] = 0.0;
+      cvatom[i][1] = 0.0;
+      cvatom[i][2] = 0.0;
+      cvatom[i][3] = 0.0;
+      cvatom[i][4] = 0.0;
+      cvatom[i][5] = 0.0;
+      cvatom[i][6] = 0.0;
+      cvatom[i][7] = 0.0;
+      cvatom[i][8] = 0.0;
+      cvatom[i][9] = 0.0;
+    }
+  }
 
   // if vflag_global = 2 and pair::compute() calls virial_fdotr_compute()
   // compute global virial via (F dot r) instead of via pairwise summation
@@ -831,7 +868,7 @@ void Pair::ev_setup(int eflag, int vflag, int alloc)
   if (vflag_global == 2 && no_virial_fdotr_compute == 0) {
     vflag_fdotr = 1;
     vflag_global = 0;
-    if (vflag_atom == 0) vflag_either = 0;
+    if (vflag_atom == 0 && cvflag_atom == 0) vflag_either = 0;
     if (vflag_either == 0 && eflag_either == 0) evflag = 0;
   } else vflag_fdotr = 0;
 
@@ -863,6 +900,7 @@ void Pair::ev_unset()
   vflag_either = 0;
   vflag_global = 0;
   vflag_atom = 0;
+  cvflag_atom = 0;
   vflag_fdotr = 0;
 }
 
@@ -1760,6 +1798,7 @@ double Pair::memory_usage()
 {
   double bytes = comm->nthreads*maxeatom * sizeof(double);
   bytes += comm->nthreads*maxvatom*6 * sizeof(double);
+  bytes += comm->nthreads*maxcvatom*9 * sizeof(double);
   return bytes;
 }
 

src/pair.h

@@ -36,6 +36,7 @@ class Pair : protected Pointers {
   double eng_vdwl,eng_coul;      // accumulated energies
   double virial[6];              // accumulated virial
   double *eatom,**vatom;         // accumulated per-atom energy/virial
+  double **cvatom;               // accumulated per-atom centroid virial
 
   double cutforce;               // max cutoff for all atom pairs
   double **cutsq;                // cutoff sq for each atom pair
@@ -65,13 +66,18 @@ class Pair : protected Pointers {
   int spinflag;                  // 1 if compatible with spin solver
   int reinitflag;                // 1 if compatible with fix adapt and alike
 
+  int cntratmstressflag;         // compatibility with centroid atomic stress
+                                 // 1 if same as pairwise atomic stress
+                                 // 2 if implemented and different from pairwise
+                                 // 4 if not compatible/implemented
+
   int tail_flag;                 // pair_modify flag for LJ tail correction
   double etail,ptail;            // energy/pressure tail corrections
   double etail_ij,ptail_ij;
 
   int evflag;                    // energy,virial settings
   int eflag_either,eflag_global,eflag_atom;
-  int vflag_either,vflag_global,vflag_atom;
+  int vflag_either,vflag_global,vflag_atom,cvflag_atom;
 
   int ncoultablebits;            // size of Coulomb table, accessed by KSpace
   int ndisptablebits;            // size of dispersion table
@@ -229,7 +235,7 @@ class Pair : protected Pointers {
 
  protected:
   int vflag_fdotr;
-  int maxeatom,maxvatom;
+  int maxeatom,maxvatom,maxcvatom;
 
   int copymode;   // if set, do not deallocate during destruction
                   // required when classes are used as functors by Kokkos