diff --git a/src/dump.cpp b/src/dump.cpp
index 21c1b16f75..df39f3738d 100644
--- a/src/dump.cpp
+++ b/src/dump.cpp
@@ -330,8 +330,6 @@ void Dump::write()
 
   if (delay_flag && update->ntimestep < delaystep) return;
 
-  printf("DUMP %ld\n",update->ntimestep);
-
   // if file per timestep, open new file
 
   if (multifile) openfile();
diff --git a/src/integrate.cpp b/src/integrate.cpp
index 52d34fb943..7a1dbfaf34 100644
--- a/src/integrate.cpp
+++ b/src/integrate.cpp
@@ -20,6 +20,7 @@
 #include "kspace.h"
 #include "modify.h"
 #include "pair.h"
+#include "output.h"
 #include "update.h"
 
 using namespace LAMMPS_NS;
@@ -115,7 +116,13 @@ void Integrate::ev_setup()
 
 /* ----------------------------------------------------------------------
    set eflag,vflag for current iteration
-   based on computes that need energy/virial info on this timestep
+   based on
+     (1) computes that need energy/virial info on this timestep
+     (2) time dumps that need unknown per-atom info on this timestep
+     NOTE: could not check time dumps if timestep size is not varying
+           see NOTE in output.cpp
+           also inefficient to add all per-atom eng/virial computes
+           but don't know which ones the dump needs
    invoke matchstep() on all timestep-dependent computes to clear their arrays
    eflag: set any or no bits
      ENERGY_GLOBAL bit for global energy
@@ -133,6 +140,10 @@ void Integrate::ev_set(bigint ntimestep)
 {
   int i,flag;
 
+  int tdflag = 0;
+  if (output->any_time_dumps) 
+    tdflag = output->check_time_dumps(ntimestep);
+
   flag = 0;
   int eflag_global = 0;
   for (i = 0; i < nelist_global; i++)
@@ -143,7 +154,7 @@ void Integrate::ev_set(bigint ntimestep)
   int eflag_atom = 0;
   for (i = 0; i < nelist_atom; i++)
     if (elist_atom[i]->matchstep(ntimestep)) flag = 1;
-  if (flag) eflag_atom = ENERGY_ATOM;
+  if (flag || (tdflag && nelist_atom)) eflag_atom = ENERGY_ATOM;
 
   if (eflag_global) update->eflag_global = ntimestep;
   if (eflag_atom) update->eflag_atom = ntimestep;
@@ -159,13 +170,13 @@ void Integrate::ev_set(bigint ntimestep)
   int vflag_atom = 0;
   for (i = 0; i < nvlist_atom; i++)
     if (vlist_atom[i]->matchstep(ntimestep)) flag = 1;
-  if (flag) vflag_atom = VIRIAL_ATOM;
+  if (flag || (tdflag && nvlist_atom)) vflag_atom = VIRIAL_ATOM;
 
   flag = 0;
   int cvflag_atom = 0;
   for (i = 0; i < ncvlist_atom; i++)
     if (cvlist_atom[i]->matchstep(ntimestep)) flag = 1;
-  if (flag) cvflag_atom = VIRIAL_CENTROID;
+  if (flag || (tdflag && ncvlist_atom)) cvflag_atom = VIRIAL_CENTROID;
 
   if (vflag_global) update->vflag_global = ntimestep;
   if (vflag_atom || cvflag_atom) update->vflag_atom = ntimestep;
diff --git a/src/output.cpp b/src/output.cpp
index 30248e449d..94688cd74c 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -133,7 +133,9 @@ void Output::init()
   }
 
   for (int i = 0; i < ndump; i++) dump[i]->init();
-  for (int i = 0; i < ndump; i++)
+  any_time_dumps = 0;
+  for (int i = 0; i < ndump; i++) {
+    if (mode_dump[i]) any_time_dumps = 1;
     if ((mode_dump[i] == 0 && every_dump[i] == 0) ||
         (mode_dump[i] == 1 && every_time_dump[i] == 0.0)) {
       ivar_dump[i] = input->variable->find(var_dump[i]);
@@ -142,6 +144,7 @@ void Output::init()
       if (!input->variable->equalstyle(ivar_dump[i]))
         error->all(FLERR,"Variable for dump every or delta is invalid style");
     }
+  }
 
   if (restart_flag_single && restart_every_single == 0) {
     ivar_restart_single = input->variable->find(var_restart_single);
@@ -176,9 +179,11 @@ void Output::setup(int memflag)
   if (ndump && update->restrict_output == 0) {
     for (int idump = 0; idump < ndump; idump++) {
 
-      // wrap dumps that invoke computes or do variable eval with clear/add
+      // wrap step dumps that invoke computes or do variable eval with clear/add
+      // see NOTE in write() about also wrapping time dumps
 
-      if (dump[idump]->clearstep || var_dump[idump])
+      if (mode_dump[idump] == 0 &&
+          (dump[idump]->clearstep || var_dump[idump]))
         modify->clearstep_compute();
 
       // write a snapshot at setup only if any of these 3 conditions hold
@@ -226,7 +231,8 @@ void Output::setup(int memflag)
       // if dump not written now, use addstep_compute_all() 
       // since don't know what computes the dump will invoke
 
-      if (dump[idump]->clearstep || var_dump[idump]) {
+      if (mode_dump[idump] == 0 &&
+          (dump[idump]->clearstep || var_dump[idump])) {
         if (writeflag) modify->addstep_compute(next_dump[idump]);
         else modify->addstep_compute_all(next_dump[idump]);
       }
@@ -239,413 +245,435 @@ void Output::setup(int memflag)
 
   } else next_dump_any = update->laststep + 1;
 
-  // do not write restart files at start of run
-  // set next_restart values to multiple of every or variable value
-  // wrap variable eval with clear/add
-  // if no restarts, set next_restart to last+1 so will not influence next
+   // do not write restart files at start of run
+   // set next_restart values to multiple of every or variable value
+   // wrap variable eval with clear/add
+   // if no restarts, set next_restart to last+1 so will not influence next
 
-  if (restart_flag && update->restrict_output == 0) {
-    if (restart_flag_single) {
-      if (restart_every_single)
-        next_restart_single =
-          (ntimestep/restart_every_single)*restart_every_single +
-          restart_every_single;
-      else {
-        bigint nextrestart = static_cast<bigint>
-          (input->variable->compute_equal(ivar_restart_single));
-        if (nextrestart <= ntimestep)
-          error->all(FLERR,"Restart variable returned a bad timestep");
-        next_restart_single = nextrestart;
-      }
-    } else next_restart_single = update->laststep + 1;
-    if (restart_flag_double) {
-      if (restart_every_double)
-        next_restart_double =
-          (ntimestep/restart_every_double)*restart_every_double +
-          restart_every_double;
-      else {
-        bigint nextrestart = static_cast<bigint>
-          (input->variable->compute_equal(ivar_restart_double));
-        if (nextrestart <= ntimestep)
-          error->all(FLERR,"Restart variable returned a bad timestep");
-        next_restart_double = nextrestart;
-      }
-    } else next_restart_double = update->laststep + 1;
-    next_restart = MIN(next_restart_single,next_restart_double);
-  } else next_restart = update->laststep + 1;
+   if (restart_flag && update->restrict_output == 0) {
+     if (restart_flag_single) {
+       if (restart_every_single)
+         next_restart_single =
+           (ntimestep/restart_every_single)*restart_every_single +
+           restart_every_single;
+       else {
+         bigint nextrestart = static_cast<bigint>
+           (input->variable->compute_equal(ivar_restart_single));
+         if (nextrestart <= ntimestep)
+           error->all(FLERR,"Restart variable returned a bad timestep");
+         next_restart_single = nextrestart;
+       }
+     } else next_restart_single = update->laststep + 1;
+     if (restart_flag_double) {
+       if (restart_every_double)
+         next_restart_double =
+           (ntimestep/restart_every_double)*restart_every_double +
+           restart_every_double;
+       else {
+         bigint nextrestart = static_cast<bigint>
+           (input->variable->compute_equal(ivar_restart_double));
+         if (nextrestart <= ntimestep)
+           error->all(FLERR,"Restart variable returned a bad timestep");
+         next_restart_double = nextrestart;
+       }
+     } else next_restart_double = update->laststep + 1;
+     next_restart = MIN(next_restart_single,next_restart_double);
+   } else next_restart = update->laststep + 1;
 
-  // print memory usage unless being called between multiple runs
+   // print memory usage unless being called between multiple runs
 
-  if (memflag) memory_usage();
+   if (memflag) memory_usage();
 
-  // set next_thermo to multiple of every or variable eval if var defined
-  // insure thermo output on last step of run
-  // thermo may invoke computes so wrap with clear/add
+   // set next_thermo to multiple of every or variable eval if var defined
+   // insure thermo output on last step of run
+   // thermo may invoke computes so wrap with clear/add
 
-  modify->clearstep_compute();
+   modify->clearstep_compute();
 
-  thermo->header();
-  thermo->compute(0);
-  last_thermo = ntimestep;
+   thermo->header();
+   thermo->compute(0);
+   last_thermo = ntimestep;
 
-  if (var_thermo) {
-    next_thermo = static_cast<bigint>
-      (input->variable->compute_equal(ivar_thermo));
-    if (next_thermo <= ntimestep)
-      error->all(FLERR,"Thermo every variable returned a bad timestep");
-  } else if (thermo_every) {
-    next_thermo = (ntimestep/thermo_every)*thermo_every + thermo_every;
-    next_thermo = MIN(next_thermo,update->laststep);
-  } else next_thermo = update->laststep;
+   if (var_thermo) {
+     next_thermo = static_cast<bigint>
+       (input->variable->compute_equal(ivar_thermo));
+     if (next_thermo <= ntimestep)
+       error->all(FLERR,"Thermo every variable returned a bad timestep");
+   } else if (thermo_every) {
+     next_thermo = (ntimestep/thermo_every)*thermo_every + thermo_every;
+     next_thermo = MIN(next_thermo,update->laststep);
+   } else next_thermo = update->laststep;
 
-  modify->addstep_compute(next_thermo);
+   modify->addstep_compute(next_thermo);
 
-  // next = next timestep any output will be done
+   // next = next timestep any output will be done
 
-  next = MIN(next_dump_any,next_restart);
-  next = MIN(next,next_thermo);
-}
+   next = MIN(next_dump_any,next_restart);
+   next = MIN(next,next_thermo);
+ }
 
-/* ----------------------------------------------------------------------
-   perform all output for this timestep
-   only perform output if next matches current step and last output doesn't
-   do dump/restart before thermo so thermo CPU time will include them
-------------------------------------------------------------------------- */
+ /* ----------------------------------------------------------------------
+    perform all output for this timestep
+    only perform output if next matches current step and last output doesn't
+    do dump/restart before thermo so thermo CPU time will include them
+ ------------------------------------------------------------------------- */
 
-void Output::write(bigint ntimestep)
+ void Output::write(bigint ntimestep)
+ {
+   // perform dump if its next_dump = current ntimestep
+   //   but not if it was already written on this step
+   // set next_dump and also next_time_dump for mode_dump = 1
+   // set next_dump_any to smallest next_dump
+   // wrap step dumps that invoke computes or do variable eval with clear/add
+   // NOTE:
+   //   could wrap time dumps as well, if timestep size did not vary
+   //   if wrap when timestep size varies frequently,
+   //     then can do many unneeded addstep() --> inefficient
+   //   hard to know if timestep varies, since run every could change it
+   //   can't remove an uneeded addstep from a compute, b/c don't know
+   //     what other command may have added it
+
+   int writeflag;
+
+   if (next_dump_any == ntimestep) {
+     for (int idump = 0; idump < ndump; idump++) {
+       if (next_dump[idump] == ntimestep) {
+         if (last_dump[idump] == ntimestep) continue;
+
+         if (mode_dump[idump] == 0 && 
+             (dump[idump]->clearstep || var_dump[idump]))
+           modify->clearstep_compute();
+
+         // perform dump
+         // reset next_dump and next_time_dump, 1 arg for write()
+
+         dump[idump]->write();
+         last_dump[idump] = ntimestep;
+         calculate_next_dump(1,idump,ntimestep);
+
+         if (mode_dump[idump] == 0 && 
+             (dump[idump]->clearstep || var_dump[idump]))
+           modify->addstep_compute(next_dump[idump]);
+       }
+
+       if (idump) next_dump_any = MIN(next_dump_any,next_dump[idump]);
+       else next_dump_any = next_dump[0];
+     }
+   }
+
+   // next_restart does not force output on last step of run
+   // for toggle = 0, replace "*" with current timestep in restart filename
+   // next restart variable may invoke computes so wrap with clear/add
+
+   if (next_restart == ntimestep) {
+     if (next_restart_single == ntimestep) {
+
+       std::string file = restart1;
+       std::size_t found = file.find('*');
+       if (found != std::string::npos)
+         file.replace(found,1,fmt::format("{}",update->ntimestep));
+
+       if (last_restart != ntimestep) restart->write(file);
+
+       if (restart_every_single) next_restart_single += restart_every_single;
+       else {
+         modify->clearstep_compute();
+         bigint nextrestart = static_cast<bigint>
+           (input->variable->compute_equal(ivar_restart_single));
+         if (nextrestart <= ntimestep)
+           error->all(FLERR,"Restart variable returned a bad timestep");
+         next_restart_single = nextrestart;
+         modify->addstep_compute(next_restart_single);
+       }
+     }
+     if (next_restart_double == ntimestep) {
+       if (last_restart != ntimestep) {
+         if (restart_toggle == 0) {
+           restart->write(restart2a);
+           restart_toggle = 1;
+         } else {
+           restart->write(restart2b);
+           restart_toggle = 0;
+         }
+       }
+       if (restart_every_double) next_restart_double += restart_every_double;
+       else {
+         modify->clearstep_compute();
+         bigint nextrestart = static_cast<bigint>
+           (input->variable->compute_equal(ivar_restart_double));
+         if (nextrestart <= ntimestep)
+           error->all(FLERR,"Restart variable returned a bad timestep");
+         next_restart_double = nextrestart;
+         modify->addstep_compute(next_restart_double);
+       }
+     }
+     last_restart = ntimestep;
+     next_restart = MIN(next_restart_single,next_restart_double);
+   }
+
+   // insure next_thermo forces output on last step of run
+   // thermo may invoke computes so wrap with clear/add
+
+   if (next_thermo == ntimestep) {
+     modify->clearstep_compute();
+     if (last_thermo != ntimestep) thermo->compute(1);
+     last_thermo = ntimestep;
+     if (var_thermo) {
+       next_thermo = static_cast<bigint>
+         (input->variable->compute_equal(ivar_thermo));
+       if (next_thermo <= ntimestep)
+         error->all(FLERR,"Thermo every variable returned a bad timestep");
+     } else if (thermo_every) next_thermo += thermo_every;
+     else next_thermo = update->laststep;
+     next_thermo = MIN(next_thermo,update->laststep);
+     modify->addstep_compute(next_thermo);
+   }
+
+   // next = next timestep any output will be done
+
+   next = MIN(next_dump_any,next_restart);
+   next = MIN(next,next_thermo);
+ }
+
+ /* ----------------------------------------------------------------------
+    force a snapshot to be written for all dumps
+    called from PRD and TAD
+ ------------------------------------------------------------------------- */
+
+ void Output::write_dump(bigint ntimestep)
+ {
+   for (int idump = 0; idump < ndump; idump++) {
+     dump[idump]->write();
+     last_dump[idump] = ntimestep;
+   }
+ }
+
+ /* ----------------------------------------------------------------------
+    calculate when next dump occurs for Dump instance idump
+    operates in one of two modes, based on mode_dump flag
+    for timestep mode, set next_dump
+    for simulation time mode, set next_time_dump and next_dump
+    which flag depends on caller
+      0 = from setup() at start of run
+      1 = from write() during run each time a dump file is written
+      2 = from reset_dt() called from fix dt/reset when it changes timestep size
+ ------------------------------------------------------------------------- */
+
+  void Output::calculate_next_dump(int which, int idump, bigint ntimestep)
+ {
+   // dump mode is by timestep
+   // just set next_dump
+
+   if (mode_dump[idump] == 0) {
+
+     if (every_dump[idump]) {
+
+       // which = 0: nextdump = next multiple of every_dump
+       // which = 1: increment nextdump by every_dump
+
+       if (which == 0)
+         next_dump[idump] =
+           (ntimestep/every_dump[idump])*every_dump[idump] + every_dump[idump];
+       else if (which == 1) 
+         next_dump[idump] += every_dump[idump];
+
+     } else {
+       next_dump[idump] = static_cast<bigint>
+         (input->variable->compute_equal(ivar_dump[idump]));
+       if (next_dump[idump] <= ntimestep)
+         error->all(FLERR,"Dump every variable returned a bad timestep");
+     }
+
+   // dump mode is by simulation time
+   // set next_time_dump and next_dump
+
+   } else {
+
+     bigint nextdump;
+     double nexttime;
+     double tcurrent = update->atime + 
+       (ntimestep - update->atimestep) * update->dt;
+
+     if (every_time_dump[idump] > 0.0) {
+
+       // which = 0: nexttime = next multiple of every_time_dump
+       // which = 1: increment nexttime by every_time_dump
+       // which = 2: no change to previous nexttime (only timestep has changed)
+
+       if (which == 0)
+         nexttime = static_cast<bigint> (tcurrent/every_time_dump[idump]) * 
+           every_time_dump[idump] + every_time_dump[idump];
+       else if (which == 1) 
+         nexttime = next_time_dump[idump] + every_time_dump[idump];
+       else if (which == 2)
+         nexttime = next_time_dump[idump];
+
+       nextdump = ntimestep + 
+         static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
+                              update->dt) + 1;
+
+       // if delta is too small to reach next timestep, use multiple of delta
+
+       if (nextdump == ntimestep) {
+         double tnext = update->atime + 
+           (ntimestep+1 - update->atimestep) * update->dt;
+         int multiple = static_cast<int> 
+           ((tnext - nexttime) / every_time_dump[idump]);
+         nexttime = nexttime + (multiple+1)*every_time_dump[idump];
+         nextdump = ntimestep + 
+           static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
+                                update->dt) + 1;
+       }
+
+     } else {
+
+       // do not re-evaulate variable for which = 2, leave nexttime as-is
+       // unless next_time_dump < 0.0, which means variable never yet evaluated
+
+       if (which < 2 || next_time_dump[idump] < 0.0) {
+         nexttime = input->variable->compute_equal(ivar_dump[idump]);
+       } else 
+         nexttime = next_time_dump[idump];
+
+       if (nexttime <= tcurrent)
+         error->all(FLERR,"Dump every/time variable returned a bad time");
+
+       nextdump = ntimestep + 
+         static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
+                              update->dt) + 1;
+       if (nextdump <= ntimestep)
+         error->all(FLERR,"Dump every/time variable too small for next timestep");
+     }
+
+     next_time_dump[idump] = nexttime;
+     next_dump[idump] = nextdump;
+   }
+ }
+
+/* ---------------------------------------------------------------------- */
+
+int Output::check_time_dumps(bigint ntimestep)
 {
-  // perform dump if its next_dump = current ntimestep
-  //   but not if it was already written on this step
-  // set next_dump and also next_time_dump for mode_dump = 1
-  // set next_dump_any to smallest next_dump
-  // wrap dumps that invoke computes or do variable eval with clear/add
+  int nowflag = 0;
+  for (int i = 0; i < ndump; i++)
+    if (mode_dump[i] && next_dump[i] == ntimestep) nowflag = 1;
 
-  int writeflag;
-
-  if (next_dump_any == ntimestep) {
-    for (int idump = 0; idump < ndump; idump++) {
-      if (next_dump[idump] == ntimestep) {
-        if (last_dump[idump] == ntimestep) continue;
-
-        if (dump[idump]->clearstep || var_dump[idump])
-          modify->clearstep_compute();
-
-        // perform dump
-        // reset next_dump and next_time_dump, 1 arg for write()
-
-        dump[idump]->write();
-        last_dump[idump] = ntimestep;
-        calculate_next_dump(1,idump,ntimestep);
-
-        if (dump[idump]->clearstep || var_dump[idump])
-          modify->addstep_compute(next_dump[idump]);
-      }
-
-      if (idump) next_dump_any = MIN(next_dump_any,next_dump[idump]);
-      else next_dump_any = next_dump[0];
-    }
-  }
-
-  // next_restart does not force output on last step of run
-  // for toggle = 0, replace "*" with current timestep in restart filename
-  // next restart variable may invoke computes so wrap with clear/add
-
-  if (next_restart == ntimestep) {
-    if (next_restart_single == ntimestep) {
-
-      std::string file = restart1;
-      std::size_t found = file.find('*');
-      if (found != std::string::npos)
-        file.replace(found,1,fmt::format("{}",update->ntimestep));
-
-      if (last_restart != ntimestep) restart->write(file);
-
-      if (restart_every_single) next_restart_single += restart_every_single;
-      else {
-        modify->clearstep_compute();
-        bigint nextrestart = static_cast<bigint>
-          (input->variable->compute_equal(ivar_restart_single));
-        if (nextrestart <= ntimestep)
-          error->all(FLERR,"Restart variable returned a bad timestep");
-        next_restart_single = nextrestart;
-        modify->addstep_compute(next_restart_single);
-      }
-    }
-    if (next_restart_double == ntimestep) {
-      if (last_restart != ntimestep) {
-        if (restart_toggle == 0) {
-          restart->write(restart2a);
-          restart_toggle = 1;
-        } else {
-          restart->write(restart2b);
-          restart_toggle = 0;
-        }
-      }
-      if (restart_every_double) next_restart_double += restart_every_double;
-      else {
-        modify->clearstep_compute();
-        bigint nextrestart = static_cast<bigint>
-          (input->variable->compute_equal(ivar_restart_double));
-        if (nextrestart <= ntimestep)
-          error->all(FLERR,"Restart variable returned a bad timestep");
-        next_restart_double = nextrestart;
-        modify->addstep_compute(next_restart_double);
-      }
-    }
-    last_restart = ntimestep;
-    next_restart = MIN(next_restart_single,next_restart_double);
-  }
-
-  // insure next_thermo forces output on last step of run
-  // thermo may invoke computes so wrap with clear/add
-
-  if (next_thermo == ntimestep) {
-    modify->clearstep_compute();
-    if (last_thermo != ntimestep) thermo->compute(1);
-    last_thermo = ntimestep;
-    if (var_thermo) {
-      next_thermo = static_cast<bigint>
-        (input->variable->compute_equal(ivar_thermo));
-      if (next_thermo <= ntimestep)
-        error->all(FLERR,"Thermo every variable returned a bad timestep");
-    } else if (thermo_every) next_thermo += thermo_every;
-    else next_thermo = update->laststep;
-    next_thermo = MIN(next_thermo,update->laststep);
-    modify->addstep_compute(next_thermo);
-  }
-
-  // next = next timestep any output will be done
-
-  next = MIN(next_dump_any,next_restart);
-  next = MIN(next,next_thermo);
+  return nowflag;
 }
 
-/* ----------------------------------------------------------------------
-   force a snapshot to be written for all dumps
-   called from PRD and TAD
-------------------------------------------------------------------------- */
+ /* ----------------------------------------------------------------------
+    force restart file(s) to be written
+    called from PRD and TAD
+ ------------------------------------------------------------------------- */
 
-void Output::write_dump(bigint ntimestep)
-{
-  for (int idump = 0; idump < ndump; idump++) {
-    dump[idump]->write();
-    last_dump[idump] = ntimestep;
-  }
-}
+ void Output::write_restart(bigint ntimestep)
+ {
+   if (restart_flag_single) {
+     std::string file = restart1;
+     std::size_t found = file.find('*');
+     if (found != std::string::npos)
+       file.replace(found,1,fmt::format("{}",update->ntimestep));
+     restart->write(file);
+   }
+
+   if (restart_flag_double) {
+     if (restart_toggle == 0) {
+       restart->write(restart2a);
+       restart_toggle = 1;
+     } else {
+       restart->write(restart2b);
+       restart_toggle = 0;
+     }
+   }
+
+   last_restart = ntimestep;
+ }
+
+ /* ----------------------------------------------------------------------
+    timestep is being changed, called by update->reset_timestep()
+    for dumps, require that no dump is "active"
+      meaning that a snapshot has already been output
+    reset next output values for restart and thermo
+    reset to smallest value >= new timestep
+    if next timestep set by variable evaluation,
+      eval for ntimestep-1, so current ntimestep can be returned if needed
+      no guarantee that variable can be evaluated for ntimestep-1
+      e.g. if it depends on computes, but live with that rare case for now
+ ------------------------------------------------------------------------- */
+
+ void Output::reset_timestep(bigint ntimestep)
+ {
+   next_dump_any = MAXBIGINT;
+   for (int idump = 0; idump < ndump; idump++)
+     if (last_dump[idump] >= 0)
+       error->all(FLERR,
+                  "Cannot reset timestep with active dump - must undump first");
+
+   if (restart_flag_single) {
+     if (restart_every_single) {
+       next_restart_single =
+         (ntimestep/restart_every_single)*restart_every_single;
+       if (next_restart_single < ntimestep)
+         next_restart_single += restart_every_single;
+     } else {
+       modify->clearstep_compute();
+       update->ntimestep--;
+       bigint nextrestart = static_cast<bigint>
+         (input->variable->compute_equal(ivar_restart_single));
+       if (nextrestart < ntimestep)
+         error->all(FLERR,"Restart variable returned a bad timestep");
+       update->ntimestep++;
+       next_restart_single = nextrestart;
+       modify->addstep_compute(next_restart_single);
+     }
+   } else next_restart_single = update->laststep + 1;
+
+   if (restart_flag_double) {
+     if (restart_every_double) {
+       next_restart_double =
+         (ntimestep/restart_every_double)*restart_every_double;
+       if (next_restart_double < ntimestep)
+         next_restart_double += restart_every_double;
+     } else {
+       modify->clearstep_compute();
+       update->ntimestep--;
+       bigint nextrestart = static_cast<bigint>
+         (input->variable->compute_equal(ivar_restart_double));
+       if (nextrestart < ntimestep)
+         error->all(FLERR,"Restart variable returned a bad timestep");
+       update->ntimestep++;
+       next_restart_double = nextrestart;
+       modify->addstep_compute(next_restart_double);
+     }
+   } else next_restart_double = update->laststep + 1;
+
+   next_restart = MIN(next_restart_single,next_restart_double);
+
+   if (var_thermo) {
+     modify->clearstep_compute();
+     update->ntimestep--;
+     next_thermo = static_cast<bigint>
+       (input->variable->compute_equal(ivar_thermo));
+     if (next_thermo < ntimestep)
+       error->all(FLERR,"Thermo_modify every variable returned a bad timestep");
+     update->ntimestep++;
+     next_thermo = MIN(next_thermo,update->laststep);
+     modify->addstep_compute(next_thermo);
+   } else if (thermo_every) {
+     next_thermo = (ntimestep/thermo_every)*thermo_every;
+     if (next_thermo < ntimestep) next_thermo += thermo_every;
+     next_thermo = MIN(next_thermo,update->laststep);
+   } else next_thermo = update->laststep;
+
+   next = MIN(next_dump_any,next_restart);
+   next = MIN(next,next_thermo);
+ }
 
 /* ----------------------------------------------------------------------
-   calculate when next dump occurs for Dump instance idump
-   operates in one of two modes, based on mode_dump flag
-   for timestep mode, set next_dump
-   for simulation time mode, set next_time_dump and next_dump
-   which flag depends on caller
-     0 = from setup() at start of run
-     1 = from write() during run each time a dump file is written
-     2 = from reset_dt() called from fix dt/reset when it changes timestep size
-------------------------------------------------------------------------- */
-
- void Output::calculate_next_dump(int which, int idump, bigint ntimestep)
-{
-  // dump mode is by timestep
-  // just set next_dump
-
-  if (mode_dump[idump] == 0) {
-
-    if (every_dump[idump]) {
-
-      // which = 0: nextdump = next multiple of every_dump
-      // which = 1: increment nextdump by every_dump
-
-      if (which == 0)
-        next_dump[idump] =
-          (ntimestep/every_dump[idump])*every_dump[idump] + every_dump[idump];
-      else if (which == 1) 
-        next_dump[idump] += every_dump[idump];
-
-    } else {
-      next_dump[idump] = static_cast<bigint>
-        (input->variable->compute_equal(ivar_dump[idump]));
-      if (next_dump[idump] <= ntimestep)
-        error->all(FLERR,"Dump every variable returned a bad timestep");
-    }
-
-  // dump mode is by simulation time
-  // set next_time_dump and next_dump
-
-  } else {
-
-    bigint nextdump;
-    double nexttime;
-    double tcurrent = update->atime + 
-      (ntimestep - update->atimestep) * update->dt;
-
-    if (every_time_dump[idump] > 0.0) {
-
-      // which = 0: nexttime = next multiple of every_time_dump
-      // which = 1: increment nexttime by every_time_dump
-      // which = 2: no change to previous nexttime (only timestep has changed)
-
-      if (which == 0)
-        nexttime = static_cast<bigint> (tcurrent/every_time_dump[idump]) * 
-          every_time_dump[idump] + every_time_dump[idump];
-      else if (which == 1) 
-        nexttime = next_time_dump[idump] + every_time_dump[idump];
-      else if (which == 2)
-        nexttime = next_time_dump[idump];
-
-      nextdump = ntimestep + 
-        static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
-                             update->dt) + 1;
-
-      // if delta is too small to reach next timestep, use multiple of delta
-
-      if (nextdump == ntimestep) {
-        double tnext = update->atime + 
-          (ntimestep+1 - update->atimestep) * update->dt;
-        int multiple = static_cast<int> 
-          ((tnext - nexttime) / every_time_dump[idump]);
-        nexttime = nexttime + (multiple+1)*every_time_dump[idump];
-        nextdump = ntimestep + 
-          static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
-                               update->dt) + 1;
-      }
-
-    } else {
-
-      // do not re-evaulate variable for which = 2, leave nexttime as-is
-      // unless next_time_dump < 0.0, which means variable never yet evaluated
-
-      if (which < 2 || next_time_dump[idump] < 0.0) {
-        nexttime = input->variable->compute_equal(ivar_dump[idump]);
-      } else 
-        nexttime = next_time_dump[idump];
-
-      if (nexttime <= tcurrent)
-        error->all(FLERR,"Dump every/time variable returned a bad time");
-
-      nextdump = ntimestep + 
-        static_cast<bigint> ((nexttime - tcurrent - EPSDT*update->dt) / 
-                             update->dt) + 1;
-      if (nextdump <= ntimestep)
-        error->all(FLERR,"Dump every/time variable too small for next timestep");
-    }
-
-    next_time_dump[idump] = nexttime;
-    next_dump[idump] = nextdump;
-  }
-}
-
-/* ----------------------------------------------------------------------
-   force restart file(s) to be written
-   called from PRD and TAD
-------------------------------------------------------------------------- */
-
-void Output::write_restart(bigint ntimestep)
-{
-  if (restart_flag_single) {
-    std::string file = restart1;
-    std::size_t found = file.find('*');
-    if (found != std::string::npos)
-      file.replace(found,1,fmt::format("{}",update->ntimestep));
-    restart->write(file);
-  }
-
-  if (restart_flag_double) {
-    if (restart_toggle == 0) {
-      restart->write(restart2a);
-      restart_toggle = 1;
-    } else {
-      restart->write(restart2b);
-      restart_toggle = 0;
-    }
-  }
-
-  last_restart = ntimestep;
-}
-
-/* ----------------------------------------------------------------------
-   timestep is being changed, called by update->reset_timestep()
-   for dumps, require that no dump is "active"
-     meaning that a snapshot has already been output
-   reset next output values restart and thermo output
-   reset to smallest value >= new timestep
-   if next timestep set by variable evaluation,
-     eval for ntimestep-1, so current ntimestep can be returned if needed
-     no guarantee that variable can be evaluated for ntimestep-1
-     e.g. if it depends on computes, but live with that rare case for now
-------------------------------------------------------------------------- */
-
-void Output::reset_timestep(bigint ntimestep)
-{
-  next_dump_any = MAXBIGINT;
-  for (int idump = 0; idump < ndump; idump++)
-    if (last_dump[idump] >= 0)
-      error->all(FLERR,
-                 "Cannot reset timestep with active dump - must undump first");
-
-  if (restart_flag_single) {
-    if (restart_every_single) {
-      next_restart_single =
-        (ntimestep/restart_every_single)*restart_every_single;
-      if (next_restart_single < ntimestep)
-        next_restart_single += restart_every_single;
-    } else {
-      modify->clearstep_compute();
-      update->ntimestep--;
-      bigint nextrestart = static_cast<bigint>
-        (input->variable->compute_equal(ivar_restart_single));
-      if (nextrestart < ntimestep)
-        error->all(FLERR,"Restart variable returned a bad timestep");
-      update->ntimestep++;
-      next_restart_single = nextrestart;
-      modify->addstep_compute(next_restart_single);
-    }
-  } else next_restart_single = update->laststep + 1;
-
-  if (restart_flag_double) {
-    if (restart_every_double) {
-      next_restart_double =
-        (ntimestep/restart_every_double)*restart_every_double;
-      if (next_restart_double < ntimestep)
-        next_restart_double += restart_every_double;
-    } else {
-      modify->clearstep_compute();
-      update->ntimestep--;
-      bigint nextrestart = static_cast<bigint>
-        (input->variable->compute_equal(ivar_restart_double));
-      if (nextrestart < ntimestep)
-        error->all(FLERR,"Restart variable returned a bad timestep");
-      update->ntimestep++;
-      next_restart_double = nextrestart;
-      modify->addstep_compute(next_restart_double);
-    }
-  } else next_restart_double = update->laststep + 1;
-
-  next_restart = MIN(next_restart_single,next_restart_double);
-
-  if (var_thermo) {
-    modify->clearstep_compute();
-    update->ntimestep--;
-    next_thermo = static_cast<bigint>
-      (input->variable->compute_equal(ivar_thermo));
-    if (next_thermo < ntimestep)
-      error->all(FLERR,"Thermo_modify every variable returned a bad timestep");
-    update->ntimestep++;
-    next_thermo = MIN(next_thermo,update->laststep);
-    modify->addstep_compute(next_thermo);
-  } else if (thermo_every) {
-    next_thermo = (ntimestep/thermo_every)*thermo_every;
-    if (next_thermo < ntimestep) next_thermo += thermo_every;
-    next_thermo = MIN(next_thermo,update->laststep);
-  } else next_thermo = update->laststep;
-
-  next = MIN(next_dump_any,next_restart);
-  next = MIN(next,next_thermo);
-}
-
-/* ----------------------------------------------------------------------
-   timestep size is being changed, called by fix dt/reset (at end of step)
+   timestep size is being changed
    reset next output values for dumps which have mode_dump=1
+   called by fix dt/reset (at end of step)
+   or called by timestep command via run every (also at end of step)
 ------------------------------------------------------------------------- */
 
 void Output::reset_dt()
@@ -659,21 +687,10 @@ void Output::reset_dt()
 
       // reset next_dump but do not change next_time_dump, 2 arg for reset_dt()
       // do not invoke for a dump already scheduled for this step
-      // use compute_all() b/c don't know what computes will be needed
+      //   since timestep change affects next step
 
       if (next_dump[idump] != ntimestep) {
         calculate_next_dump(2,idump,update->ntimestep);
-
-        // NOTE: think I should not do this here
-        // for time dumps, calc_next_dump should calc the next timestep
-        //   as one less and not add it to computes
-        // then on that step, write() should not actually write the dump
-        //   but trigger it on next step and addstep_compute_all for that step
-        // b/c when write() is called, the next-step timestep is set
-        // unless run every timestep is invoked in-between!
-
-        //if (dump[idump]->clearstep || var_dump[idump])
-        //  modify->addstep_compute_all(next_dump[idump]);
       }
     }
 
@@ -684,6 +701,7 @@ void Output::reset_dt()
   next = MIN(next,next_thermo);
 }
 
+
 /* ----------------------------------------------------------------------
    add a Dump to list of Dumps
 ------------------------------------------------------------------------- */
diff --git a/src/output.h b/src/output.h
index c8d3f734e0..c7c4faf252 100644
--- a/src/output.h
+++ b/src/output.h
@@ -36,6 +36,7 @@ class Output : protected Pointers {
   int ndump;               // # of Dumps defined
   int max_dump;            // max size of Dump list
   bigint next_dump_any;    // next timestep for any Dump
+  int any_time_dumps;      // 1 if any time dump defined
   int *mode_dump;          // 0/1 if write every N timesteps or Delta in sim time
   int *every_dump;         // dump every N timesteps, 0 if variable
   double *every_time_dump; // dump every Delta of sim time, 0.0 if variable
@@ -75,13 +76,14 @@ class Output : protected Pointers {
   void write(bigint);             // output for current timestep
   void write_dump(bigint);        // force output of dump snapshots
   void write_restart(bigint);     // force output of a restart file
-  void reset_timestep(bigint);    // reset output which depeneds on timestep
-  void reset_dt();                // reset output which depends on dt
+  void reset_timestep(bigint);    // reset output which depends on timestep
+  void reset_dt();                // reset output which depends on timestep size
 
   void add_dump(int, char **);       // add a Dump to Dump list
   void modify_dump(int, char **);    // modify a Dump
   void delete_dump(char *);          // delete a Dump from Dump list
   int find_dump(const char *);       // find a Dump ID
+  int check_time_dumps(bigint);      // check if any time dump is output now
 
   void set_thermo(int, char **);        // set thermo output freqquency
   void create_thermo(int, char **);     // create a thermo style
diff --git a/src/verlet.cpp b/src/verlet.cpp
index 348639ef05..342dc3d951 100644
--- a/src/verlet.cpp
+++ b/src/verlet.cpp
@@ -252,8 +252,6 @@ void Verlet::run(int n)
     ntimestep = ++update->ntimestep;
     ev_set(ntimestep);
 
-    printf("VERLET %ld: %d %d\n",ntimestep,eflag,vflag);
-
     // initial time integration
 
     timer->stamp();