#include <cassert>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <string>
#include <sstream>
#include <fstream>

#include <cctk.h>
#include <cctk_Parameters.h>
#include <cctki_GHExtensions.h>
#include <cctki_ScheduleBindings.h>
#include <cctki_WarnLevel.h>

#include <Requirements.hh>

#include <CactusTimerSet.hh>
#include <Timer.hh>

#include <carpet.hh>



namespace Carpet {
  
  using namespace std;
  
  
  
  static void CallSetup (cGH * cctkGH);
  static void CallRecoverVariables (cGH * cctkGH);
#if 0
  static void CallRegridRecoverMeta (cGH * cctkGH);
#endif
  static void CallRegridRecoverLevel (cGH * cctkGH);
  static void CallRegridInitialMeta (cGH * cctkGH);
  static void CallRegridInitialLevel (cGH * cctkGH);
  static void CallPostRecoverVariables (cGH * cctkGH);
  static void CallInitial (cGH * cctkGH);
  static void CallRestrict (cGH * cctkGH);
  static void CallPostInitial (cGH * cctkGH);
  static void CallAnalysis (cGH * cctkGH, bool did_recover);
  
  static void Initialise3tl (cGH * cctkGH);
  
  static void print_internal_data ();
  
  static void ScheduleTraverse
  (char const * where, char const * name, cGH * cctkGH);
  static void OutputGH (char const * where, cGH * cctkGH);
  
  
  
  int
  Initialise (tFleshConfig * const fc)
  {
    DECLARE_CCTK_PARAMETERS;
    
    int const convlev = 0;
    cGH * const cctkGH = CCTK_SetupGH (fc, convlev);
    CCTKi_AddGH (fc, convlev, cctkGH);

    do_global_mode = true;
    do_early_global_mode = true;
    do_late_global_mode = true;
    do_meta_mode = true;
    do_early_meta_mode = true;
    do_late_meta_mode = true;
    global_time = cctk_initial_time;
    delta_time = 1.0;
    for (int ml = 0; ml < mglevels; ++ ml) {
      // assert (leveltimes.AT(ml).size() == 1);
      // leveltimes.AT(ml).AT(0) = global_time;
      for (int rl = 0; rl < reflevels; ++ rl) {
        CCTK_REAL const dt = delta_time / timereffacts.AT(rl);
        for (int tl = 0; tl < tt->timelevels; ++ tl) {
          tt->set_time (ml, rl, tl, global_time - tl * dt);
        }
      }
    }
    
    cctkGH->cctk_iteration = 0;
    cctkGH->cctk_time = global_time;
    cctkGH->cctk_delta_time = delta_time;
    
    static Timers::Timer timer ("Initialise");
    timer.start();
    
    // Delay checkpoint until MPI has been initialised
    Waypoint ("Starting initialisation");
    
    CCTKi_ScheduleGHInit (cctkGH); // Enable storage and communication
    GroupsStorageCheck (cctkGH);
    do_warn_about_storage = true;
    
    CCTKi_InitGHExtensions (cctkGH);
    
    // Write grid structure to file
    for (int m=0; m<maps; ++m) {
      OutputGridStructure (cctkGH, m, vhh.AT(m)->regions);
      OutputGridCoordinates (cctkGH, m, vhh.AT(m)->regions);
    } // for m
    
    CallSetup (cctkGH);
    
    if (fc->recovered) {
      // Read data from a checkpoint file
      
      CallRecoverVariables (cctkGH);
      CallPostRecoverVariables (cctkGH);
      // TODO: We should probably restrict here.
      // CallRestrict (cctkGH);
      // TODO: Should we also execute another bin after this?
      // CallPostRestrictRecover (cctkGH);
      print_internal_data ();
      
    } else {
      // Calculate initial data
      
      CallInitial (cctkGH);
      CallRestrict (cctkGH);
      CallPostInitial (cctkGH);
      print_internal_data ();
      
      if (init_3_timelevels) {
        Initialise3tl (cctkGH);
      }
    }
    
    // Analyse initial data
    CallAnalysis (cctkGH, fc->recovered);
    print_internal_data ();
    
    timer.stop();
    if (output_timers_every > 0) {
      Timers::CactusTimerSet::writeData (cctkGH, timer_file);
    }

    if (output_initialise_timer_tree) {
      Timers::Timer::outputTree("Initialise");
    }

    Waypoint ("Done with initialisation");
    
    return 0;
  }
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  
  
  
  void
  CallSetup (cGH * const cctkGH)
  {
    char const * const where = "CallSetup";
    static Timers::Timer timer (where);
    timer.start();
    
    BEGIN_MGLEVEL_LOOP(cctkGH) {
      do_early_global_mode = true;
      do_late_global_mode = true;
      do_global_mode = true;
      do_early_meta_mode = mglevel==mglevels-1;
      do_late_meta_mode = mglevel==0;
      do_meta_mode = do_early_meta_mode; // on first iteration, coarsest grid
      
      // Checking
      {
        int const rl=0;
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          Poison (cctkGH, alltimes, CCTK_ARRAY);
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      }
      
      // Register coordinates
      ScheduleTraverse (where, "CCTK_WRAGH", cctkGH);
      
      // Check parameters
      ScheduleTraverse (where, "CCTK_PARAMCHECK", cctkGH);
    } END_MGLEVEL_LOOP;
    
#ifdef REQUIREMENTS_HH
    // TODO: Why is this disabled?
    // Requirements::CheckRequirements (cctkGH);
#endif
    
    CCTKi_FinaliseParamWarn();
    
    timer.stop();
  }
  
  
  
  void
  CallRecoverVariables (cGH * const cctkGH)
  {
    char const * const where = "CallRecoverVariables";
    static Timers::Timer timer (where);
    timer.start();
    
    DECLARE_CCTK_PARAMETERS;
    
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_early_global_mode = reflevel==0;
          do_late_global_mode = reflevel==reflevels-1;
          do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
          do_late_meta_mode = do_late_global_mode and mglevel==0;
          do_global_mode = do_early_global_mode; // on first iteration, coarsest grid
          do_meta_mode = do_early_meta_mode; // on first iteration, coarsest grid
          
          // cctkGH->cctk_time = global_time;
          
          Waypoint ("Recover I at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
          // Checking
          Poison (cctkGH, alltimes, CCTK_GF);
          
          // Set up the grids
          ScheduleTraverse (where, "CCTK_BASEGRID", cctkGH);
          
          // Recover
          ScheduleTraverse (where, "CCTK_RECOVER_VARIABLES", cctkGH);
          
          // Timing statistics
          // (do this here, after cctk_time has been recovered)
          if (do_early_global_mode) {
            InitTimingStats (cctkGH);
          }
          
          if (regrid_during_recovery) {
            EndTimingLevel (cctkGH);
            CallRegridRecoverLevel (cctkGH);
            BeginTimingLevel (cctkGH);
          }
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
#if 0
    // TODO: Maybe do not checkpoint (nor read back) ghost and buffer
    // zones
    CallRegridRecoverMeta (cctkGH);
#endif
    
    timer.stop();
  }
  
  
  
  void
  CallPostRecoverVariables (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallPostRecoverVariables";
    static Timers::Timer timer (where);
    timer.start();
    
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_early_global_mode = reflevel==0;
          do_late_global_mode = reflevel==reflevels-1;
          do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
          do_late_meta_mode = do_late_global_mode and mglevel==0;
          do_global_mode = do_early_global_mode; // on first iteration, coarsest grid
          do_meta_mode = do_early_meta_mode; // on first iteration, coarsest grid
          
          // This has been activated and deactivated a number of times by now,
          // so I'll put down the reasoning behind deactivating it. Maybe the
          // other party in this tug of war will be able to respond. Most of
          // this is from b4429f4006e5:
          //
          // Traverse post_recover_variables in only for current timelevel (not
          // for all timelevels). Variables on past timelevels cannot have
          // their boundary conditions applied consistently, because time
          // interpolation for these may requires even older timelevels that
          // are not available.  The problem is not that prolongation in time
          // on the older timelevels will fail. Prolongation will succeed and
          // is not an extrapolation in time, so Carpet does not abort. However
          // the time slices used as sources for the interpolation differ from
          // the ones that were originally used during the evolution. This
          // means that data on the old slices differs from what was present
          // during the evolution ie. checkpointing and recovery change data
          // on the grid.
          //
          // Current wisdom (ie. Erik says) is that all grid functions with
          // multiple time levels should to be checkpointed because of this. If
          // you do not checkpoint them, then you must be able to recompute
          // them exactly using a pointwise, local, algebraic method that does
          // not rely on present values of the re-computed data on the grid.
          // This exlcudes the Hydro primitives (since con2prim requires an
          // initial guess), but would in principle (I think) work with the ADM
          // variables. 
          //
          // In particular one cannot call MoL_PostStep on all levels since it
          // involves prolongation.
          //
          // Roland Haas, June 21st 2012

#if 0
          BEGIN_TIMELEVEL_LOOP(cctkGH) {
            
            Waypoint ("Recovering II at iteration %d time %g timelevel %d%s%s",
                      cctkGH->cctk_iteration,
                      (double)cctkGH->cctk_time,
                      timelevel,
                      (do_global_mode ? " (global)" : ""),
                      (do_meta_mode ? " (meta)" : ""));
            
            // Post recover variables
            ScheduleTraverse (where, "CCTK_POST_RECOVER_VARIABLES", cctkGH);
            
          } END_TIMELEVEL_LOOP;
#else
          Waypoint ("Recovering II at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration,
                    (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
          // Post recover variables
          ScheduleTraverse (where, "CCTK_POST_RECOVER_VARIABLES", cctkGH);
#endif
          
          // Checking
          PoisonCheck (cctkGH, currenttime);
          
          CheckChecksums (cctkGH, allbutcurrenttime);
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    timer.stop();
  }
  
  
  
  void
  CallInitial (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallInitial";
    static Timers::Timer timer (where);
    timer.start();
    
    if (not regrid_during_initialisation) {
      // Regrid once in the beginning
      CallRegridInitialMeta (cctkGH);
    }
    
    // Poison early, since grid functions may be initialised in global
    // loop-local mode, ane we must not overwrite them accidentally
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          // Checking
          Poison (cctkGH, alltimes, CCTK_GF);
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_early_global_mode = reflevel==0;
          do_late_global_mode = reflevel==reflevels-1;
          do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
          do_late_meta_mode = do_late_global_mode and mglevel==0;
          do_global_mode = do_early_global_mode; // on first iteration, coarsest grid
          do_meta_mode = do_early_meta_mode; // on first iteration, coarsest grid
          
          // cctkGH->cctk_time = global_time;
          
          Waypoint ("Initialisation I at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
          // Timing statistics
          if (do_early_global_mode) {
            InitTimingStats (cctkGH);
          }
          
          // Set up the grids
          ScheduleTraverse (where, "CCTK_BASEGRID", cctkGH);
          
          if (init_each_timelevel) {
            
            BEGIN_TIMELEVEL_LOOP(cctkGH) {
              
              // Set up the initial data
              ScheduleTraverse (where, "CCTK_INITIAL", cctkGH);
              ScheduleTraverse (where, "CCTK_POSTINITIAL", cctkGH);
              
            } END_TIMELEVEL_LOOP;
            
          } else {              // not init_each_timelevel
            
            assert (do_allow_past_timelevels);
            do_allow_past_timelevels =
              not CCTK_EQUALS (initial_data_setup_method, "init_single_level");
            
            // Set up the initial data
            ScheduleTraverse (where, "CCTK_INITIAL", cctkGH);
            ScheduleTraverse (where, "CCTK_POSTINITIAL", cctkGH);
            
            do_allow_past_timelevels = true;
            
          } // not init_each_timelevel
          
          if (init_fill_timelevels) {
            FillTimeLevels (cctkGH);
          }
          
          // Checking
          PoisonCheck (cctkGH, currenttime);
          
          if (regrid_during_initialisation and mglevel==0) {
            // Regrid after initialising each level
            EndTimingLevel (cctkGH);
            CallRegridInitialLevel (cctkGH);
            BeginTimingLevel (cctkGH);
          }
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    timer.stop();
  }
  
  
  
  void
  CallRestrict (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "Initialise::CallRestrict";
    static Timers::Timer timer ("CallRestrict");
    timer.start();
    
    for (int ml=mglevels-1; ml>=0; --ml) {

      for (int rl=reflevels-2; rl>=0; --rl) {
        ENTER_GLOBAL_MODE (cctkGH, ml) {
          ENTER_LEVEL_MODE (cctkGH, rl) {
            BeginTimingLevel (cctkGH);
                    
            Waypoint ("Initialisation/Restrict at iteration %d time %g",
                      cctkGH->cctk_iteration, (double)cctkGH->cctk_time);
          
            Restrict (cctkGH);

            EndTimingLevel (cctkGH);
          } LEAVE_LEVEL_MODE;
        } LEAVE_GLOBAL_MODE;
      } // for rl

      bool have_done_global_mode = false;
      bool have_done_early_global_mode = false;
      bool have_done_late_global_mode = false;
      bool have_done_anything = false;
        
      for (int rl=0; rl<reflevels; ++rl) {
        ENTER_GLOBAL_MODE (cctkGH, ml) {
          ENTER_LEVEL_MODE (cctkGH, rl) {
            BeginTimingLevel (cctkGH);
                    
            do_early_global_mode = not have_done_early_global_mode;
            do_late_global_mode = reflevel==reflevels-1;
            do_early_meta_mode =
              do_early_global_mode and mglevel==mglevels-1;
            do_late_meta_mode = do_late_global_mode and mglevel==0;
            do_global_mode = do_late_global_mode;
            do_meta_mode = do_global_mode and do_late_meta_mode;
            assert (not (have_done_global_mode and do_global_mode));
            assert (not (have_done_early_global_mode and
                         do_early_global_mode));
            assert (not (have_done_late_global_mode and
                         do_late_global_mode));
            have_done_global_mode |= do_global_mode;
            have_done_early_global_mode |= do_early_global_mode;
            have_done_late_global_mode |= do_late_global_mode;
            have_done_anything = true;

            Waypoint ("Initialisation/PostRestrict at iteration %d time %g",
                      cctkGH->cctk_iteration, (double)cctkGH->cctk_time);
                
            ScheduleTraverse (where, "CCTK_POSTRESTRICTINITIAL", cctkGH);
            
            if (init_fill_timelevels) {
              FillTimeLevels (cctkGH);
            }
            
            EndTimingLevel (cctkGH);
          } LEAVE_LEVEL_MODE;
        } LEAVE_GLOBAL_MODE;
      } // for rl

      if (have_done_anything) assert (have_done_global_mode);
      if (have_done_anything) assert (have_done_early_global_mode);
      if (have_done_anything) assert (have_done_late_global_mode);
        
    } // for ml
    
    timer.stop();
  }
  
  
  
  void
  CallPostInitial (cGH * const cctkGH)
  {
    char const * const where = "CallPostInitial";
    static Timers::Timer timer (where);
    timer.start();
    
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_early_global_mode = reflevel==0;
          do_late_global_mode = reflevel==reflevels-1;
          do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
          do_late_meta_mode = do_late_global_mode and mglevel==0;
          do_global_mode = do_late_global_mode; // on last iteration, finest grid
          do_meta_mode = do_late_meta_mode; // on last iteration, finest grid
          
          Waypoint ("Initialisation II at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
#if 0
          if (reflevel < reflevels-1) {
            ScheduleTraverse (where, "CCTK_POSTRESTRICTINITIAL", cctkGH);
          }
#endif
          
          ScheduleTraverse (where, "CCTK_POSTPOSTINITIAL", cctkGH);
          ScheduleTraverse (where, "CCTK_POSTSTEP", cctkGH);
          
          PoisonCheck (cctkGH, alltimes);
          CheckChecksums (cctkGH, allbutcurrenttime);
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    timer.stop();
  }
  
  
  
  void
  CallAnalysis (cGH * const cctkGH, bool const did_recover)
  {
    char const * const where = "CallAnalysis";
    static Timers::Timer timer (where);
    timer.start();
    
    for (int rl=0; rl<reflevels; ++rl) {
      BEGIN_MGLEVEL_LOOP(cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_early_global_mode = reflevel==0;
          do_late_global_mode = reflevel==reflevels-1;
          do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
          do_late_meta_mode = do_late_global_mode and mglevel==0;
          do_global_mode = do_late_global_mode; // on last iteration, finest grid
          do_meta_mode = do_late_meta_mode; // on last iteration, finest grid
          
          Waypoint ("Initialisation III at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
          int const do_every =
            ipow(mgfact, mglevel) * (maxtimereflevelfact / timereffacts.AT(rl));
          if (cctkGH->cctk_iteration % do_every == 0) {
            
            if (not did_recover) {
              // Checkpoint, but only if we did not recover
              ScheduleTraverse (where, "CCTK_CPINITIAL", cctkGH);
            }
            
            // Analysis
            in_analysis_bin = true;
            ScheduleTraverse (where, "CCTK_ANALYSIS", cctkGH);
            in_analysis_bin = false;
            
            if (do_late_global_mode) {
              // Timing statistics
              UpdateTimingStats (cctkGH);
            }
            
            // Output
            OutputGH (where, cctkGH);
            
            // Checking
            PoisonCheck (cctkGH, alltimes);
            CheckChecksums (cctkGH, allbutcurrenttime);
          } // if do_every
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    timer.stop();
  }
  
  
  
#if 0
  void
  CallRegrid (cGH * const cctkGH,
              bool const callpreregrid,
              bool const callregrid,
              bool const callpostregrid,
              bool const regridinitial)
  {
    DECLARE_CCTK_PARAMETERS;
    
    assert (is_level_mode());
    
    bool const old_do_global_mode = do_global_mode;
    bool const old_do_meta_mode = do_meta_mode;
    do_global_mode = true;
    do_meta_mode = true;
    
    // Preregrid
    if (callpreregrid) {
      if (regridinitial) {
        Waypoint ("Preregridinitial at iteration %d time %g%s%s",
                  cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                  (do_global_mode ? " (global)" : ""),
                  (do_meta_mode ? " (meta)" : ""));
        ScheduleTraverse (where, "CCTK_PREREGRIDINITIAL", cctkGH);
      } else {
        Waypoint ("Preregrid at iteration %d time %g%s%s",
                  cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                  (do_global_mode ? " (global)" : ""),
                  (do_meta_mode ? " (meta)" : ""));
        ScheduleTraverse (where, "CCTK_PREREGRID", cctkGH);
      }
    }
    
    // Regrid
    bool did_regrid = false;
    if (callregrid) {
      Checkpoint ("Regrid");
      did_regrid = Regrid (cctkGH, true);
    }
    
    if (did_regrid or not callregrid) {
      BEGIN_META_MODE (cctkGH) {
        for (int rl=0; rl<reflevels; ++rl) {
          
          bool did_recompose = false;
          if (did_regrid) {
            did_recompose = Recompose (cctkGH, rl, prolongate_initial_data);
          }
          
          // Call postregridinitial only if initial data have already
          // been set up
          if (callpostregrid and (did_recompose or not callregrid)) {
            BEGIN_MGLEVEL_LOOP (cctkGH) {
              ENTER_LEVEL_MODE (cctkGH, rl) {
                BeginTimingLevel (cctkGH);
                
                do_global_mode = reflevel == reflevels - 1;
                do_meta_mode = do_global_mode and mglevel==mglevels-1;
                
                if (regridinitial) {
                  Waypoint ("Postregridinitial at iteration %d time %g%s%s",
                            cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                            (do_global_mode ? " (global)" : ""),
                            (do_meta_mode ? " (meta)" : ""));
                } else {
                  Waypoint ("Postregrid at iteration %d time %g%s%s",
                            cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                            (do_global_mode ? " (global)" : ""),
                            (do_meta_mode ? " (meta)" : ""));
                }
                
                int const num_tl =
                  regridinitial
                  ? (init_each_timelevel ? maxtimelevels : 1)
                  : maxtimelevels;
                
                bool const old_do_allow_past_timelevels =
                  do_allow_past_timelevels;
                do_allow_past_timelevels = false;
                
                // Rewind times
                for (int m=0; m<maps; ++m) {
                  CCTK_REAL const old_delta =
                    vtt.AT(m)->get_delta (reflevel, mglevel);
                  vtt.AT(m)->set_delta (reflevel, mglevel, - old_delta);
                }
                FlipTimeLevels (cctkGH);
                for (int tl=0; tl<num_tl; ++tl) {
                  for (int m=0; m<maps; ++m) {
                    vtt.AT(m)->advance_time (reflevel, mglevel);
                  }
                  CycleTimeLevels (cctkGH);
                }
                for (int m=0; m<maps; ++m) {
                  CCTK_REAL const old_delta =
                    vtt.AT(m)->get_delta (reflevel, mglevel);
                  vtt.AT(m)->set_delta (reflevel, mglevel, - old_delta);
                }
                FlipTimeLevels (cctkGH);
                CCTK_REAL const old_cctk_time = cctkGH->cctk_time;
                cctkGH->cctk_time -=
                  num_tl * (cctkGH->cctk_delta_time / cctkGH->cctk_timefac);
                
                for (int tl=0; tl<num_tl; ++tl) {
                  
                  // Advance times
                  for (int m=0; m<maps; ++m) {
                    vtt.AT(m)->advance_time (reflevel, mglevel);
                  }
                  CycleTimeLevels (cctkGH);
                  cctkGH->cctk_time +=
                    cctkGH->cctk_delta_time / cctkGH->cctk_timefac;
                  
                  // Postregrid
                  if (regridinitial) {
                    ScheduleTraverse (where, "CCTK_POSTREGRIDINITIAL", cctkGH);
                  } else {
                    ScheduleTraverse (where, "CCTK_POSTREGRID", cctkGH);
                  }
                  
                } // for tl
                cctkGH->cctk_time = old_cctk_time;
                
                do_allow_past_timelevels = old_do_allow_past_timelevels;
                
                EndTimingLevel (cctkGH);
              } LEAVE_LEVEL_MODE;
            } END_MGLEVEL_LOOP;
          } // if did_recompose
          
        } // for rl
      } END_META_MODE;
    } // if did_regrid
    
    if (callregrid) {
      RegridFree (cctkGH);
    }
    
    do_global_mode = old_do_global_mode;
    do_meta_mode = old_do_meta_mode;
  }
#endif
  
  
  
#if 0
  void
  CallRegridRecoverMeta (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallRegridRecoverMeta";
    static Timers::Timer timer (where);
    timer.start();
    
    assert (is_meta_mode());
    
    bool const old_do_global_mode = do_global_mode;
    bool const old_do_meta_mode = do_meta_mode;
    do_global_mode = true;
    do_meta_mode = true;
    
    for (int rl=0; rl<reflevels; ++rl) {
      
      BEGIN_MGLEVEL_LOOP (cctkGH) {
        ENTER_LEVEL_MODE (cctkGH, rl) {
          BeginTimingLevel (cctkGH);
          
          do_global_mode = reflevel == reflevels - 1;
          do_meta_mode = do_global_mode and mglevel==mglevels-1;
          
          Waypoint ("Postregrid at iteration %d time %g%s%s",
                    cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                    (do_global_mode ? " (global)" : ""),
                    (do_meta_mode ? " (meta)" : ""));
          
          int const num_tl = maxtimelevels;
          
          bool const old_do_allow_past_timelevels = do_allow_past_timelevels;
          do_allow_past_timelevels = false;
          
          // Rewind times
          for (int m=0; m<maps; ++m) {
            CCTK_REAL const old_delta =
              vtt.AT(m)->get_delta (reflevel, mglevel);
            vtt.AT(m)->set_delta (reflevel, mglevel, - old_delta);
          }
          FlipTimeLevels (cctkGH);
          for (int tl=0; tl<num_tl; ++tl) {
            for (int m=0; m<maps; ++m) {
              vtt.AT(m)->advance_time (reflevel, mglevel);
            }
            CycleTimeLevels (cctkGH);
          }
          for (int m=0; m<maps; ++m) {
            CCTK_REAL const old_delta =
              vtt.AT(m)->get_delta (reflevel, mglevel);
            vtt.AT(m)->set_delta (reflevel, mglevel, - old_delta);
          }
          FlipTimeLevels (cctkGH);
          CCTK_REAL const old_cctk_time = cctkGH->cctk_time;
          cctkGH->cctk_time -=
            num_tl * (cctkGH->cctk_delta_time / cctkGH->cctk_timefac);
          
          for (int tl=0; tl<num_tl; ++tl) {
            
            // Advance times
            for (int m=0; m<maps; ++m) {
              vtt.AT(m)->advance_time (reflevel, mglevel);
            }
            CycleTimeLevels (cctkGH);
            cctkGH->cctk_time +=
              cctkGH->cctk_delta_time / cctkGH->cctk_timefac;
            
            // Postregrid
            ScheduleTraverse (where, "CCTK_POSTREGRID", cctkGH);
              
          } // for tl
          cctkGH->cctk_time = old_cctk_time;
          
          do_allow_past_timelevels = old_do_allow_past_timelevels;
          
          EndTimingLevel (cctkGH);
        } LEAVE_LEVEL_MODE;
      } END_MGLEVEL_LOOP;
    } // for rl
    
    do_global_mode = old_do_global_mode;
    do_meta_mode = old_do_meta_mode;
    
    timer.stop();
  }
#endif
  
  
  
  void
  CallRegridRecoverLevel (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallRegridRecoverLevel";
    static Timers::Timer timer (where);
    timer.start();
    
    CCTK_WARN (CCTK_WARN_ALERT,
               "Regridding in level mode after recovering is discouraged");
    
    assert (is_level_mode());
    
    bool const old_do_global_mode = do_global_mode;
    bool const old_do_early_global_mode = do_early_global_mode;
    bool const old_do_late_global_mode = do_late_global_mode;
    bool const old_do_meta_mode = do_meta_mode;
    bool const old_do_early_meta_mode = do_early_meta_mode;
    bool const old_do_late_meta_mode = do_late_meta_mode;
    do_global_mode = true;
    do_early_global_mode = true;
    do_late_global_mode = true;
    do_meta_mode = true;
    do_early_meta_mode = true;
    do_late_meta_mode = true;
    
    // Preregrid
    Waypoint ("Preregrid at iteration %d time %g%s%s",
              cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
              (do_global_mode ? " (global)" : ""),
              (do_meta_mode ? " (meta)" : ""));
    ScheduleTraverse (where, "CCTK_PREREGRID", cctkGH);
    
    // Regrid
    Checkpoint ("Regrid");
    int const oldreflevels = reflevels;
    bool const did_regrid = Regrid (cctkGH, true, prolongate_initial_data);
    bool const did_remove_level = reflevels < oldreflevels;
    assert (not did_remove_level or did_regrid);
    
    if (did_regrid) {
#ifdef REQUIREMENTS_HH
      Requirements::Regrid(reflevels);
#endif
      bool did_any_recompose = false;
      BEGIN_META_MODE (cctkGH) {

        bool have_done_global_mode = false;
        bool have_done_early_global_mode = false;
        bool have_done_late_global_mode = false;
        bool have_done_anything = false;

        for (int rl=0; rl<reflevels; ++rl) {
          
          bool did_recompose = false;
          did_recompose = Recompose (cctkGH, rl, prolongate_initial_data);
          did_any_recompose = did_any_recompose or did_recompose;
#ifdef REQUIREMENTS_HH
          Requirements::Recompose(cctkGH->cctk_iteration, rl,
                                  not did_recompose ?
                                  Requirements::valid::everywhere :
                                  prolongate_initial_data ?
                                  Requirements::valid::interior :
                                  Requirements::valid::nowhere);
#endif
          
          // Carpet assumes that a regridding operation always changes "level N
          // and all finer levels" so we should call POSTREGRID on all finer levels
          if (did_any_recompose or
              (did_remove_level and rl == reflevels - 1))
          {
            BEGIN_MGLEVEL_LOOP (cctkGH) {
              ENTER_LEVEL_MODE (cctkGH, rl) {
                BeginTimingLevel (cctkGH);
                
                do_early_global_mode = not have_done_early_global_mode;
                do_late_global_mode = reflevel==reflevels-1;
                do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
                do_late_meta_mode = do_late_global_mode and mglevel==0;
                do_global_mode = do_late_global_mode;
                do_meta_mode = do_late_meta_mode;
                assert (not (have_done_global_mode and do_global_mode));
                assert (not (have_done_early_global_mode and
                             do_early_global_mode));
                assert (not (have_done_late_global_mode and
                             do_late_global_mode));
                have_done_global_mode |= do_global_mode;
                have_done_early_global_mode |= do_early_global_mode;
                have_done_late_global_mode |= do_late_global_mode;
                have_done_anything = true;
                
                BEGIN_TIMELEVEL_LOOP(cctkGH) {
                  
                  Waypoint ("Postregrid at iteration %d time %g timelevel %d%s%s",
                            cctkGH->cctk_iteration,
                            (double)cctkGH->cctk_time,
                            timelevel,
                            (do_global_mode ? " (global)" : ""),
                            (do_meta_mode ? " (meta)" : ""));
                  
                  // Postregrid
                  ScheduleTraverse (where, "CCTK_POSTREGRID", cctkGH);
                
                } END_TIMELEVEL_LOOP;
                
                EndTimingLevel (cctkGH);
              } LEAVE_LEVEL_MODE;
            } END_MGLEVEL_LOOP;
          } // if did_recompose
          
        } // for rl

        if (have_done_anything) assert (have_done_global_mode);
        if (have_done_anything) assert (have_done_early_global_mode);
        if (have_done_anything) assert (have_done_late_global_mode);
        
      } END_META_MODE;
#ifdef REQUIREMENTS_HH
      Requirements::RegridFree();
#endif
    } // if did_regrid
    
    RegridFree (cctkGH, prolongate_initial_data);
    
    do_global_mode = old_do_global_mode;
    do_early_global_mode = old_do_early_global_mode;
    do_late_global_mode = old_do_late_global_mode;
    do_meta_mode = old_do_meta_mode;
    do_early_meta_mode = old_do_early_meta_mode;
    do_late_meta_mode = old_do_late_meta_mode;
    
    timer.stop();
  }
  
  
  
  void
  CallRegridInitialMeta (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallRegridInitialMeta";
    static Timers::Timer timer (where);
    timer.start();
    
    assert (is_meta_mode());
    
    bool const old_do_global_mode = do_global_mode;
    bool const old_do_early_global_mode = do_early_global_mode;
    bool const old_do_late_global_mode = do_late_global_mode;
    bool const old_do_meta_mode = do_meta_mode;
    bool const old_do_early_meta_mode = do_early_meta_mode;
    bool const old_do_late_meta_mode = do_late_meta_mode;
    do_global_mode = true;
    do_early_global_mode = true;
    do_late_global_mode = true;
    do_meta_mode = true;
    do_early_meta_mode = true;
    do_late_meta_mode = true;
    
    ENTER_GLOBAL_MODE (cctkGH, 0) {
      ENTER_LEVEL_MODE (cctkGH, 0) {
        BeginTimingLevel (cctkGH);
        
        // Preregrid
        Waypoint ("Preregridinitial at iteration %d time %g%s%s",
                  cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                  (do_global_mode ? " (global)" : ""),
                  (do_meta_mode ? " (meta)" : ""));
        ScheduleTraverse (where, "CCTK_PREREGRIDINITIAL", cctkGH);
        
        // Regrid
        Checkpoint ("Regrid");
        bool const did_regrid = Regrid (cctkGH, true, prolongate_initial_data);
        
        if (did_regrid) {
#ifdef REQUIREMENTS_HH
          Requirements::Regrid(reflevels);
#endif
          for (int rl=0; rl<reflevels; ++rl) {
            if (not enable_no_storage) {
              Recompose (cctkGH, rl, prolongate_initial_data);
#ifdef REQUIREMENTS_HH
              Requirements::Recompose(cctkGH->cctk_iteration, rl,
                                      prolongate_initial_data ?
                                      Requirements::valid::interior :
                                      Requirements::valid::nowhere);
#endif
            }
          } // for rl
#ifdef REQUIREMENTS_HH
          Requirements::RegridFree();
#endif
        } // if did_regrid
        
        RegridFree (cctkGH, prolongate_initial_data);
        
        EndTimingLevel (cctkGH);
      } LEAVE_LEVEL_MODE;
    } LEAVE_GLOBAL_MODE;
    
    do_global_mode = old_do_global_mode;
    do_early_global_mode = old_do_early_global_mode;
    do_late_global_mode = old_do_late_global_mode;
    do_meta_mode = old_do_meta_mode;
    do_early_meta_mode = old_do_early_meta_mode;
    do_late_meta_mode = old_do_late_meta_mode;
    
    timer.stop();
  }
  
  
  
  void
  CallRegridInitialLevel (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    char const * const where = "CallRegridInitialLevel";
    static Timers::Timer timer (where);
    timer.start();
    
    CCTK_WARN (CCTK_WARN_ALERT,
               "Regridding in level mode while initialising is discouraged");
    
    assert (is_level_mode());
    
    bool const old_do_global_mode = do_global_mode;
    bool const old_do_early_global_mode = do_early_global_mode;
    bool const old_do_late_global_mode = do_late_global_mode;
    bool const old_do_meta_mode = do_meta_mode;
    bool const old_do_early_meta_mode = do_early_meta_mode;
    bool const old_do_late_meta_mode = do_late_meta_mode;
    do_global_mode = true;
    do_early_global_mode = true;
    do_late_global_mode = true;
    do_meta_mode = true;
    do_early_meta_mode = true;
    do_late_meta_mode = true;
    
    // Preregrid
    Waypoint ("Preregridinitial at iteration %d time %g%s%s",
              cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
              (do_global_mode ? " (global)" : ""),
              (do_meta_mode ? " (meta)" : ""));
    ScheduleTraverse (where, "CCTK_PREREGRIDINITIAL", cctkGH);
    
    // Regrid
    Checkpoint ("Regrid");
    int const oldreflevels = reflevels;
    bool const did_regrid = Regrid (cctkGH, true, prolongate_initial_data);
    bool const did_remove_level = reflevels < oldreflevels;
    assert (not did_remove_level or did_regrid);
    
    if (did_regrid) {
#ifdef REQUIREMENTS_HH
      Requirements::Regrid(reflevels);
#endif
      bool did_any_recompose = false;
      BEGIN_META_MODE (cctkGH) {

        bool have_done_global_mode = false;
        bool have_done_early_global_mode = false;
        bool have_done_late_global_mode = false;
        bool have_done_anything = false;

        for (int rl=0; rl<reflevels; ++rl) {
          
          bool did_recompose = Recompose (cctkGH, rl, prolongate_initial_data);
          did_any_recompose = did_any_recompose or did_recompose;
#ifdef REQUIREMENTS_HH
          Requirements::Recompose(cctkGH->cctk_iteration, rl,
                                  not did_recompose ?
                                  Requirements::valid::everywhere :
                                  prolongate_initial_data ?
                                  Requirements::valid::interior :
                                  Requirements::valid::nowhere);
#endif
          
          // Carpet assumes that a regridding operation always changes
          // "level N and all finer levels" so we should call
          // POSTREGRIDINITIAL on all finer levels
          if (did_any_recompose or
              (did_remove_level and rl == reflevels - 1))
          {
            BEGIN_MGLEVEL_LOOP (cctkGH) {
              ENTER_LEVEL_MODE (cctkGH, rl) {
                BeginTimingLevel (cctkGH);
                
                do_early_global_mode = not have_done_early_global_mode;
                do_late_global_mode = reflevel==reflevels-1;
                do_early_meta_mode =
                  do_early_global_mode and mglevel==mglevels-1;
                do_late_meta_mode = do_late_global_mode and mglevel==0;
                do_global_mode = do_late_global_mode;
                do_meta_mode = do_late_meta_mode;
                assert (not (have_done_global_mode and do_global_mode));
                assert (not (have_done_early_global_mode and
                             do_early_global_mode));
                assert (not (have_done_late_global_mode and
                             do_late_global_mode));
                have_done_global_mode |= do_global_mode;
                have_done_early_global_mode |= do_early_global_mode;
                have_done_late_global_mode |= do_late_global_mode;
                have_done_anything = true;
                
                Waypoint ("Postregridinitial at iteration %d time %g%s%s",
                          cctkGH->cctk_iteration, (double)cctkGH->cctk_time,
                          (do_global_mode ? " (global)" : ""),
                          (do_meta_mode ? " (meta)" : ""));
                
                if (init_each_timelevel) {
                  
                  BEGIN_TIMELEVEL_LOOP(cctkGH) {
                    
                    // Postregridinitial
                    ScheduleTraverse (where, "CCTK_POSTREGRIDINITIAL", cctkGH);
                    
                  } END_TIMELEVEL_LOOP;
                  
                } else {        // not init_each_timelevel
                  
                  assert (do_allow_past_timelevels);
                  do_allow_past_timelevels = false;
                  
                  // Postregridinitial
                  ScheduleTraverse (where, "CCTK_POSTREGRIDINITIAL", cctkGH);
                  
                  do_allow_past_timelevels = true;
                  
                  if (init_fill_timelevels) {
                    FillTimeLevels (cctkGH);
                  }
                  
                } // not init_each_timelevel
                
                EndTimingLevel (cctkGH);
              } LEAVE_LEVEL_MODE;
            } END_MGLEVEL_LOOP;
          } // if did_recompose
          
        } // for rl

        if (have_done_anything) assert (have_done_global_mode);
        if (have_done_anything) assert (have_done_early_global_mode);
        if (have_done_anything) assert (have_done_late_global_mode);
        
      } END_META_MODE;
#ifdef REQUIREMENTS_HH
      Requirements::RegridFree();
#endif
    } // if did_regrid
    
    RegridFree (cctkGH, prolongate_initial_data);
    
    do_global_mode = old_do_global_mode;
    do_early_global_mode = old_do_early_global_mode;
    do_late_global_mode = old_do_late_global_mode;
    do_meta_mode = old_do_meta_mode;
    do_early_meta_mode = old_do_early_meta_mode;
    do_late_meta_mode = old_do_late_meta_mode;
    
    timer.stop();
  }
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  
  
  
  static void initialise_3tl_flip_timelevels (cGH * const cctkGH);
  static void initialise_3tl_evolve (cGH * const cctkGH);
  static void initialise_3tl_recycle (cGH * const cctkGH);
  
  
  
  void
  Initialise3tl (cGH * const cctkGH)
  {
    DECLARE_CCTK_PARAMETERS;
    
    Waypoint ("Initialising three timelevels:");
    
    char const * const where = "Initialise3TL";
    static Timers::Timer timer (where);
    timer.start();

#if 0
    initialise_3tl_flip_timelevels (cctkGH);
    initialise_3tl_evolve (cctkGH);
    // TODO: May want to restrict here if possible (i.e. if the time
    // refinement factor is one)
    initialise_3tl_recycle (cctkGH);
    initialise_3tl_flip_timelevels (cctkGH);
#endif
    
    initialise_3tl_flip_timelevels (cctkGH);
    initialise_3tl_evolve (cctkGH);
    initialise_3tl_evolve (cctkGH);
    // TODO: May want to restrict where possible (i.e. if the time
    // refinement factor is one)
    initialise_3tl_recycle (cctkGH);
    initialise_3tl_recycle (cctkGH);
    initialise_3tl_flip_timelevels (cctkGH);

    timer.stop();

    Waypoint ("Finished initialising three timelevels");
  }
  
  void
  initialise_3tl_flip_timelevels (cGH * const cctkGH)
  {
    Waypoint ("Initialise3TL::Flip");
    
    delta_time *= -1;
    
    BEGIN_MGLEVEL_LOOP(cctkGH) {
      BEGIN_REFLEVEL_LOOP (cctkGH) {
        
        FlipTimeLevels (cctkGH);
        
      } END_REFLEVEL_LOOP;
    } END_MGLEVEL_LOOP;
  }
  
  void
  initialise_3tl_evolve (cGH * const cctkGH)
  {
    char const * const where = "Evolve";
    static Timers::Timer timer (where);
    timer.start();
    
    BEGIN_MGLEVEL_LOOP(cctkGH) {
      BEGIN_REFLEVEL_LOOP(cctkGH) {
        BeginTimingLevel (cctkGH);
        
        do_early_global_mode = reflevel==0;
        do_late_global_mode = reflevel==reflevels-1;
        do_early_meta_mode = do_early_global_mode and mglevel==mglevels-1;
        do_late_meta_mode = do_late_global_mode and mglevel==0;
        do_global_mode = do_early_global_mode;
        do_meta_mode = do_early_meta_mode;
        
        Waypoint ("Initialisation 3TL evolution",
                  (do_global_mode ? " (global)" : ""),
                  (do_meta_mode ? " (meta)" : ""));
        
        CycleTimeLevels (cctkGH);
        
        CalculateChecksums (cctkGH, allbutcurrenttime);
        Poison (cctkGH, currenttimebutnotifonly);
        
        // Evolve
        ScheduleTraverse (where, "CCTK_PRESTEP", cctkGH);
        ScheduleTraverse (where, "CCTK_EVOL", cctkGH);
        
        PoisonCheck (cctkGH, currenttime);
        
        EndTimingLevel (cctkGH);
      } END_REFLEVEL_LOOP;
    } END_MGLEVEL_LOOP;
    
    timer.stop();
  }
  
  void
  initialise_3tl_recycle (cGH * const cctkGH)
  {
    char const * const where = "Recycle";
    static Timers::Timer timer (where);
    timer.start();
    
    BEGIN_MGLEVEL_LOOP(cctkGH) {
      BEGIN_REFLEVEL_LOOP(cctkGH) {
        BeginTimingLevel (cctkGH);
        
        Waypoint ("Initialisation 3TL recycling");
        
        UncycleTimeLevels (cctkGH);
        
        EndTimingLevel (cctkGH);
      } END_REFLEVEL_LOOP;
    } END_MGLEVEL_LOOP;
    
    timer.stop();
  }
  
  
  
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  //////////////////////////////////////////////////////////////////////////////
  
  void
  print_internal_data ()
  {
    DECLARE_CCTK_PARAMETERS;
    
    if (output_internal_data) {
      CCTK_INFO ("Internal data dump:");
      streamsize const oldprecision = cout.precision();
      cout.precision (17);
      cout << "   global_time: " << global_time << endl
        // << "   leveltimes: " << leveltimes << endl
           << "   delta_time: " << delta_time << endl;
      cout.precision (oldprecision);
    }
  }
  
  
  
  void ScheduleTraverse (char const * const where, char const * const name,
                         cGH * const cctkGH)
  {
    Timers::Timer timer(name);

    timer.start();
    ostringstream infobuf;
    infobuf << "Scheduling " << name;
    string const info = infobuf.str();
    Checkpoint (info.c_str());
    CCTK_ScheduleTraverse (name, cctkGH, CallFunction);
    timer.stop();
  }
  
  void OutputGH (char const * const where, cGH * const cctkGH)
  {
    static Timers::Timer timer("OutputGH");
    timer.start();
    CCTK_OutputGH (cctkGH);
    timer.stop();
  }
  
  
  
} // namespace Carpet