write_data: directly replace types w labels

allow direct replacement of numeric atom types in Atoms sections with type labels, using new keyword

doc/src/write_data.rst

@@ -19,6 +19,7 @@ Syntax
        *nocoeff* = do not write out force field info
        *nofix* = do not write out extra sections read by fixes
        *nolabelmap* = do not write out the default label map
+       *types_style* value = *numeric* or *labels*
        *pair* value = *ii* or *ij*
          *ii* = write one line of pair coefficient info per atom type
          *ij* = write one line of pair coefficient info per IJ atom type pair
@@ -112,7 +113,12 @@ not be written to the data file (see the Type Label sections of
 default label map is fully defined for a given interaction, i.e. every
 atom, bond, angle, dihedral or improper type has an associated type
 label, then a type label section for that interaction is written to
-the data file.
+the data file. The *types_style* keyword indicates how atom, bond,
+etc. types are written in the Atoms, Bonds, etc. sections. If the
+value is specified as *numeric*, then numeric types are used. If the
+value is specified as *labels*, then interaction types are written as
+type labels using the default label map. When using type labels, the
+default label map must be written to the data file.
 
 The *pair* keyword lets you specify in what format the pair
 coefficient information is written into the data file.  If the value
@@ -153,4 +159,4 @@ Related commands
 Default
 """""""
 
-The option defaults are pair = ii.
+The option defaults are pair = ii and types_style = numeric.

src/atom.h

@@ -33,6 +33,7 @@ class Atom : protected Pointers {
   enum { GROW = 0, RESTART = 1, BORDER = 2 };
   enum { ATOMIC = 0, MOLECULAR = 1, TEMPLATE = 2 };
   enum { ATOM = 0, BOND = 1, ANGLE = 2, DIHEDRAL = 3, IMPROPER = 4 };
+  enum { NUMERIC = 0, LABELS = 1};
   enum { MAP_NONE = 0, MAP_ARRAY = 1, MAP_HASH = 2, MAP_YES = 3 };
 
   // atom counts
@@ -175,7 +176,7 @@ class Atom : protected Pointers {
   // most are existence flags for per-atom vectors and arrays
   // 1 if variable is used, 0 if not
 
-  int labelmapflag;
+  int labelmapflag, types_style;
   int sphere_flag, ellipsoid_flag, line_flag, tri_flag, body_flag;
   int peri_flag, electron_flag;
   int wavepacket_flag, sph_flag;

src/atom_vec.cpp

@@ -20,6 +20,7 @@
 #include "error.h"
 #include "fix.h"
 #include "force.h"
+#include "label_map.h"
 #include "math_const.h"
 #include "memory.h"
 #include "modify.h"
@@ -1866,6 +1867,11 @@ void AtomVec::write_data(FILE *fp, int n, double **buf)
         }
       } else if (datatype == Atom::INT) {
         if (cols == 0) {
+          if (atom->types_style == Atom::LABELS &&
+              strcmp(atom->peratom[mdata_atom.index[nn]].name,"type") == 0) {
+            fmt::print(fp," {}",atom->lmaps[0]->typelabel[ubuf(buf[i][j++]).i-1]);
+            continue;
+          }
           fmt::print(fp," {}",ubuf(buf[i][j++]).i);
         } else {
           for (m = 0; m < cols; m++)

src/write_data.cpp

@@ -73,6 +73,7 @@ void WriteData::command(int narg, char **arg)
   coeffflag = 1;
   fixflag = 1;
   lmapflag = 1;
+  atom->types_style = Atom::NUMERIC;
   int noinit = 0;
 
   int iarg = 1;
@@ -95,6 +96,12 @@ void WriteData::command(int narg, char **arg)
     } else if (strcmp(arg[iarg],"nolabelmap") == 0) {
       lmapflag = 0;
       iarg++;
+    } else if (strcmp(arg[iarg],"types_style") == 0) {
+      if (iarg+2 > narg) error->all(FLERR,"Illegal write_data command");
+      if (strcmp(arg[iarg+1],"numeric") == 0) atom->types_style = Atom::NUMERIC;
+      else if (strcmp(arg[iarg+1],"labels") == 0) atom->types_style = Atom::LABELS;
+      else error->all(FLERR,"Illegal write_data command");
+      iarg += 2;
     } else error->all(FLERR,"Illegal write_data command");
   }