diff --git a/src/modify.cpp b/src/modify.cpp
index d0656d3895..427c4e259b 100644
--- a/src/modify.cpp
+++ b/src/modify.cpp
@@ -191,11 +191,7 @@ void Modify::init()
 
   for (i = 0; i < ncompute; i++) {
     compute[i]->init();
-    compute[i]->invoked_scalar = -1;
-    compute[i]->invoked_vector = -1;
-    compute[i]->invoked_array = -1;
-    compute[i]->invoked_peratom = -1;
-    compute[i]->invoked_local = -1;
+    compute[i]->init_flags();
   }
   addstep_compute_all(update->ntimestep);
 
diff --git a/src/thermo.cpp b/src/thermo.cpp
index 6122edec83..bdf2b8cf7b 100644
--- a/src/thermo.cpp
+++ b/src/thermo.cpp
@@ -1134,8 +1134,8 @@ void Thermo::check_temp(const std::string &keyword)
   if (!temperature)
     error->all(FLERR, "Thermo keyword {} in variable requires thermo to use/init temperature",
                keyword);
-  if (update->first_update == 0)
-    error->all(FLERR,"Thermo keyword {} cannot be invoked before first run",keyword);
+  if (!temperature->is_initialized())
+    error->all(FLERR,"Thermo keyword {} cannot be invoked before initialized by run",keyword);
   if (!(temperature->invoked_flag & Compute::INVOKED_SCALAR)) {
     temperature->compute_scalar();
     temperature->invoked_flag |= Compute::INVOKED_SCALAR;
@@ -1153,8 +1153,8 @@ void Thermo::check_pe(const std::string &keyword)
   if (!pe)
     error->all(FLERR, "Thermo keyword {} in variable requires thermo to use/init potential energy",
                keyword);
-  if (update->first_update == 0)
-    error->all(FLERR,"Thermo keyword {} cannot be invoked before first run",keyword);
+  if (!pe->is_initialized())
+    error->all(FLERR,"Thermo keyword {} cannot be invoked before initialized by run",keyword);
   if (!(pe->invoked_flag & Compute::INVOKED_SCALAR)) {
     pe->compute_scalar();
     pe->invoked_flag |= Compute::INVOKED_SCALAR;
@@ -1169,8 +1169,8 @@ void Thermo::check_press_scalar(const std::string &keyword)
 {
   if (!pressure)
     error->all(FLERR, "Thermo keyword {} in variable requires thermo to use/init press", keyword);
-  if (update->first_update == 0)
-    error->all(FLERR,"Thermo keyword {} cannot be invoked before first run",keyword);
+  if (!pressure->is_initialized())
+    error->all(FLERR,"Thermo keyword {} cannot be invoked before initialized by run",keyword);
   if (!(pressure->invoked_flag & Compute::INVOKED_SCALAR)) {
     pressure->compute_scalar();
     pressure->invoked_flag |= Compute::INVOKED_SCALAR;
@@ -1185,8 +1185,8 @@ void Thermo::check_press_vector(const std::string &keyword)
 {
   if (!pressure)
     error->all(FLERR, "Thermo keyword {} in variable requires thermo to use/init press", keyword);
-  if (update->first_update == 0)
-    error->all(FLERR,"Thermo keyword {} cannot be invoked before first run",keyword);
+  if (!pressure->is_initialized())
+    error->all(FLERR,"Thermo keyword {} cannot be invoked before initialized by run",keyword);
   if (!(pressure->invoked_flag & Compute::INVOKED_VECTOR)) {
     pressure->compute_vector();
     pressure->invoked_flag |= Compute::INVOKED_VECTOR;
diff --git a/src/variable.cpp b/src/variable.cpp
index 3264cfa1ee..7cbd43b7c6 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -1505,8 +1505,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
 
         if (nbracket == 0 && compute->scalar_flag && lowercase) {
 
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_SCALAR)) {
             compute->compute_scalar();
             compute->invoked_flag |= Compute::INVOKED_SCALAR;
@@ -1527,8 +1527,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
           if (index1 > compute->size_vector &&
               compute->size_vector_variable == 0)
             print_var_error(FLERR,"Variable formula compute vector is accessed out-of-range",ivar,0);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_VECTOR)) {
             compute->compute_vector();
             compute->invoked_flag |= Compute::INVOKED_VECTOR;
@@ -1553,8 +1553,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
             print_var_error(FLERR,"Variable formula compute array is accessed out-of-range",ivar,0);
           if (index2 > compute->size_array_cols)
             print_var_error(FLERR,"Variable formula compute array is accessed out-of-range",ivar,0);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_ARRAY)) {
             compute->compute_array();
             compute->invoked_flag |= Compute::INVOKED_ARRAY;
@@ -1580,8 +1580,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
             print_var_error(FLERR,"Compute global vector in atom-style variable formula",ivar);
           if (compute->size_vector == 0)
             print_var_error(FLERR,"Variable formula compute vector is zero length",ivar);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_VECTOR)) {
             compute->compute_vector();
             compute->invoked_flag |= Compute::INVOKED_VECTOR;
@@ -1604,8 +1604,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
             print_var_error(FLERR,"Compute global vector in atom-style variable formula",ivar);
           if (compute->size_array_rows == 0)
             print_var_error(FLERR,"Variable formula compute array is zero length",ivar);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_ARRAY)) {
             compute->compute_array();
             compute->invoked_flag |= Compute::INVOKED_ARRAY;
@@ -1623,8 +1623,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
         } else if (nbracket == 1 && compute->peratom_flag &&
                    compute->size_peratom_cols == 0) {
 
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_PERATOM)) {
             compute->compute_peratom();
             compute->invoked_flag |= Compute::INVOKED_PERATOM;
@@ -1640,8 +1640,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
 
           if (index2 > compute->size_peratom_cols)
             print_var_error(FLERR,"Variable formula compute array is accessed out-of-range",ivar,0);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_PERATOM)) {
             compute->compute_peratom();
             compute->invoked_flag |= Compute::INVOKED_PERATOM;
@@ -1663,8 +1663,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
             print_var_error(FLERR,"Per-atom compute in equal-style variable formula",ivar);
           if (treetype == VECTOR)
             print_var_error(FLERR,"Per-atom compute in vector-style variable formula",ivar);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_PERATOM)) {
             compute->compute_peratom();
             compute->invoked_flag |= Compute::INVOKED_PERATOM;
@@ -1687,8 +1687,8 @@ double Variable::evaluate(char *str, Tree **tree, int ivar)
             print_var_error(FLERR,"Per-atom compute in vector-style variable formula",ivar);
           if (index1 > compute->size_peratom_cols)
             print_var_error(FLERR,"Variable formula compute array is accessed out-of-range",ivar,0);
-          if (update->first_update == 0)
-            print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+          if (!compute->is_initialized())
+            print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
           if (!(compute->invoked_flag & Compute::INVOKED_PERATOM)) {
             compute->compute_peratom();
             compute->invoked_flag |= Compute::INVOKED_PERATOM;
@@ -4163,8 +4163,8 @@ int Variable::special_function(char *word, char *contents, Tree **tree, Tree **t
         print_var_error(FLERR,mesg,ivar);
       }
       if (index == 0 && compute->vector_flag) {
-        if (update->first_update == 0)
-          print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+        if (!compute->is_initialized())
+          print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
         if (!(compute->invoked_flag & Compute::INVOKED_VECTOR)) {
           compute->compute_vector();
           compute->invoked_flag |= Compute::INVOKED_VECTOR;
@@ -4174,8 +4174,8 @@ int Variable::special_function(char *word, char *contents, Tree **tree, Tree **t
       } else if (index && compute->array_flag) {
         if (index > compute->size_array_cols)
           print_var_error(FLERR,"Variable formula compute array is accessed out-of-range",ivar,0);
-        if (update->first_update == 0)
-          print_var_error(FLERR,"Variable formula compute cannot be invoked before first run",ivar);
+        if (!compute->is_initialized())
+          print_var_error(FLERR,"Variable formula compute cannot be invoked before initialized by run",ivar);
         if (!(compute->invoked_flag & Compute::INVOKED_ARRAY)) {
           compute->compute_array();
           compute->invoked_flag |= Compute::INVOKED_ARRAY;