add labelmap function to variable command

src/variable.cpp

@@ -24,6 +24,7 @@
 #include "info.h"
 #include "input.h"
 #include "lmppython.h"
+#include "label_map.h"
 #include "math_const.h"
 #include "memory.h"
 #include "modify.h"
@@ -2067,7 +2068,7 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
       } else {
 
         // ----------------
-        // math or group or special function
+        // math or group or special or labelmap function
         // ----------------
 
         if (str[i] == '(') {
@@ -2081,7 +2082,9 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
                                   argstack,nargstack,ivar));
           else if (special_function(word,contents,tree,treestack,ntreestack,
                                     argstack,nargstack,ivar));
-          else print_var_error(FLERR,fmt::format("Invalid math/group/special "
+          else if (labelmap_function(word,contents,tree,treestack,ntreestack,
+                                     argstack,nargstack,ivar));
+          else print_var_error(FLERR,fmt::format("Invalid math/group/special/labelmap "
                                                  "function '{}()'in variable "
                                                  "formula", word),ivar);
           delete [] contents;
@@ -4508,6 +4511,69 @@ int Variable::special_function(char *word, char *contents, Tree **tree,
   return 1;
 }
 
+/* ----------------------------------------------------------------------
+   process a type label function in formula
+   push result (numeric type) onto tree or arg stack
+   word = interaction type
+   contents = str between parentheses (one type label)
+   return 0 if not a match, 1 if successfully processed
+   customize by adding a label map function:
+     label(typelabel),blabel(typelabel),alabel(typelabel),
+     dlabel(typelabel),ilabel(typelabel)
+------------------------------------------------------------------------- */
+
+int Variable::labelmap_function(char *word, char *contents, Tree **tree,
+                                Tree **treestack, int &ntreestack,
+                                double *argstack, int &nargstack, int ivar)
+{
+  // word not a match to any label map function
+
+  if (strcmp(word,"label") && strcmp(word,"blabel") &&
+      strcmp(word,"alabel") && strcmp(word,"dlabel") &&
+      strcmp(word,"ilabel"))
+    return 0;
+
+  if (!atom->labelmapflag)
+    print_var_error(FLERR,"Invalid type label in "
+                    "variable formula",ivar);
+
+  int value;
+  std::string typestr = contents;
+
+  if (strcmp(word,"label") == 0) {
+    value = atom->lmap->find(typestr,atom->lmap->typelabel,atom->ntypes);
+
+  } else if (strcmp(word,"blabel") == 0) {
+    value = atom->lmap->find(typestr,atom->lmap->btypelabel,atom->nbondtypes);
+
+  } else if (strcmp(word,"alabel") == 0) {
+    value = atom->lmap->find(typestr,atom->lmap->atypelabel,atom->nangletypes);
+
+  } else if (strcmp(word,"dlabel") == 0) {
+    value = atom->lmap->find(typestr,atom->lmap->dtypelabel,atom->ndihedraltypes);
+
+  } else if (strcmp(word,"ilabel") == 0) {
+    value = atom->lmap->find(typestr,atom->lmap->itypelabel,atom->nimpropertypes);
+  }
+
+  if (value == -1)
+    print_var_error(FLERR,"Invalid type label in "
+                    "variable formula",ivar);
+
+  // save value in tree or on argstack
+
+  if (tree) {
+    Tree *newtree = new Tree();
+    newtree->type = VALUE;
+    newtree->value = value;
+    newtree->first = newtree->second = nullptr;
+    newtree->nextra = 0;
+    treestack[ntreestack++] = newtree;
+  } else argstack[nargstack++] = value;
+
+  return 1;
+}
+
 /* ----------------------------------------------------------------------
    extract a global value from a per-atom quantity in a formula
    flag = 0 -> word is an atom vector

src/variable.h

@@ -118,6 +118,8 @@ class Variable : protected Pointers {
   int region_function(char *, int);
   int special_function(char *, char *, Tree **, Tree **,
                        int &, double *, int &, int);
+  int labelmap_function(char *, char *, Tree **, Tree **,
+                        int &, double *, int &, int);
   void peratom2global(int, char *, double *, int, tagint,
                       Tree **, Tree **, int &, double *, int &);
   int is_atom_vector(char *);