synchronize interface to managing computes in Modify with that of fixes

- add find_compute_by_style()
- add delete_compute(int)

src/modify.cpp

@@ -1326,7 +1326,12 @@ void Modify::delete_compute(const std::string &id)
 {
   int icompute = find_compute(id);
   if (icompute < 0) error->all(FLERR,"Could not find compute ID to delete");
-  delete compute[icompute];
+  delete_compute(icompute);
+}
+
+void Modify::delete_compute(int icompute)
+{
+  if (compute[icompute]) delete compute[icompute];
 
   // move other Computes down in list one slot
 
@@ -1347,6 +1352,20 @@ int Modify::find_compute(const std::string &id)
   return -1;
 }
 
+/* ----------------------------------------------------------------------
+   find a compute by style
+   return index of compute or -1 if not found
+------------------------------------------------------------------------- */
+
+int Modify::find_compute_by_style(const char *style)
+{
+  int icompute;
+  for (icompute = 0; icompute < ncompute; icompute++)
+    if (utils::strmatch(compute[icompute]->style,style)) break;
+  if (icompute == ncompute) return -1;
+  return icompute;
+}
+
 /* ----------------------------------------------------------------------
    clear invoked flag of all computes
    called everywhere that computes are used, before computes are invoked

src/modify.h

@@ -109,21 +109,24 @@ class Modify : protected Pointers {
   void delete_fix(int);
   int find_fix(const std::string &);
   int find_fix_by_style(const char *);
-  int check_package(const char *);
-  int check_rigid_group_overlap(int);
-  int check_rigid_region_overlap(int, class Region *);
-  int check_rigid_list_overlap(int *);
 
   void add_compute(int, char **, int trysuffix=1);
   void add_compute(const std::string &, int trysuffix=1);
   void modify_compute(int, char **);
   void delete_compute(const std::string &);
+  void delete_compute(int);
   int find_compute(const std::string &);
+  int find_compute_by_style(const char *);
 
   void clearstep_compute();
   void addstep_compute(bigint);
   void addstep_compute_all(bigint);
 
+  int check_package(const char *);
+  int check_rigid_group_overlap(int);
+  int check_rigid_region_overlap(int, class Region *);
+  int check_rigid_list_overlap(int *);
+
   void write_restart(FILE *);
   int read_restart(FILE *);
   void restart_deallocate(int);