Task: Implement ioascii.hh for Carpet/CarpetIOASCII thorn

thorn_name: Carpet/CarpetIOASCII
src_filename: ioascii.hh
interface: # Interface definition for thorn CarpetIOASCII

IMPLEMENTS: IOASCII

uses include header: Timer.hh

uses include header: carpet.hh

uses include header: dist.hh

uses include header: vect.hh

uses include header: data.hh
uses include header: gdata.hh

uses include header: gf.hh
uses include header: ggf.hh

uses include header: typecase.hh
uses include header: typeprops.hh

CCTK_INT last_output_iteration[4] TYPE=scalar
CCTK_REAL last_output_time[4] TYPE=scalar
CCTK_INT this_iteration[4] TYPE=scalar


# Check whether existing output files should be truncated or not
CCTK_INT FUNCTION \
    IO_TruncateOutputFiles (CCTK_POINTER_TO_CONST IN cctkGH)
REQUIRES FUNCTION IO_TruncateOutputFiles



# Determine which boundaries are symmetry boundaries
CCTK_INT FUNCTION \
    SymmetryTableHandleForGrid (CCTK_POINTER_TO_CONST IN cctkGH)
REQUIRES FUNCTION SymmetryTableHandleForGrid

CCTK_INT FUNCTION \
    SymmetryTableHandleForGI (CCTK_POINTER_TO_CONST IN cctkGH, \
                              CCTK_INT IN group_index)
REQUIRES FUNCTION SymmetryTableHandleForGI



# Return a pointer to an unmodifiable C string
# which contains a unique ID for this build
CCTK_POINTER_TO_CONST \
FUNCTION UniqueBuildID (CCTK_POINTER_TO_CONST IN cctkGH)
USES FUNCTION UniqueBuildID

# Return a pointer to an unmodifiable C string
# which contains a unique ID for this simulation
CCTK_POINTER_TO_CONST \
FUNCTION UniqueSimulationID (CCTK_POINTER_TO_CONST IN cctkGH)
USES FUNCTION UniqueSimulationID

# Return a pointer to an unmodifiable C string
# which contains a unique ID for this run
CCTK_POINTER_TO_CONST \
FUNCTION UniqueRunID (CCTK_POINTER_TO_CONST IN cctkGH)
USES FUNCTION UniqueRunID

schedule: # Schedule definitions for thorn CarpetIOASCII

STORAGE: last_output_iteration last_output_time this_iteration

SCHEDULE CarpetIOASCIIStartup AT startup AFTER IOUtil_Startup
{
  LANG: C
  OPTIONS: global
} "Startup routine"

SCHEDULE CarpetIOASCIIInit AT initial
{
  LANG: C
  OPTIONS: global
} "Initialisation routine"

param: # Parameter definitions for thorn CarpetIOASCII



shares: IO

USES STRING out_dir

USES KEYWORD out_criterion
USES CCTK_INT out_every
USES CCTK_REAL out_dt



USES CCTK_INT out_xline_yi
USES CCTK_INT out_xline_zi
USES CCTK_INT out_yline_xi
USES CCTK_INT out_yline_zi
USES CCTK_INT out_zline_xi
USES CCTK_INT out_zline_yi

USES CCTK_REAL out_xline_y
USES CCTK_REAL out_xline_z
USES CCTK_REAL out_yline_x
USES CCTK_REAL out_yline_z
USES CCTK_REAL out_zline_x
USES CCTK_REAL out_zline_y



USES CCTK_INT out_xyplane_zi
USES CCTK_INT out_xzplane_yi
USES CCTK_INT out_yzplane_xi

USES CCTK_REAL out_xyplane_z
USES CCTK_REAL out_xzplane_y
USES CCTK_REAL out_yzplane_x



USES BOOLEAN new_filename_scheme
USES BOOLEAN strict_io_parameter_check
USES KEYWORD out_fileinfo
USES KEYWORD verbose
USES STRING out_group_separator



private:


# this affects a static variable (created_files in ioascii.cc) which controls
# file truncation and thus it should not change during a single segment
BOOLEAN one_file_per_group "Write one file per group instead of per variable" STEERABLE = RECOVER
{
} "no"



BOOLEAN output_all_timelevels "Output all timelevels instead of only the current" STEERABLE = ALWAYS
{
} "no"



BOOLEAN separate_grids "Separate grid levels in the output file by additional empty lines" STEERABLE = ALWAYS
{
} "yes"

BOOLEAN separate_components "Separate grid components in the output file by additional empty lines" STEERABLE = ALWAYS
{
} "no"



BOOLEAN compact_format "Use a more compact output format with fewer columns and lines" STEERABLE = ALWAYS
{
} "no"



BOOLEAN use_grid_coordinates "Use grid coordinate grid functions to obtain coordinate locations" STEERABLE = ALWAYS
{
} "no"



INT out_precision "How many digits to output floating-point numbers with" STEERABLE = ALWAYS
{
  0:* :: "Number of precision digits"
} 15



CCTK_STRING out0D_dir "Name of 0D ASCII output directory, overrides IO::out_dir" STEERABLE = ALWAYS
{
  "^$" :: "Empty: use IO::out_dir"
  ".+" :: "Not empty: directory name"
} ""

CCTK_STRING out1D_dir "Name of 1D ASCII output directory, overrides IO::out_dir" STEERABLE = ALWAYS
{
  "^$" :: "Empty: use IO::out_dir"
  ".+" :: "Not empty: directory name"
} ""

CCTK_STRING out2D_dir "Name of 2D ASCII output directory, overrides IO::out_dir" STEERABLE = ALWAYS
{
  "^$" :: "Empty: use IO::out_dir"
  ".+" :: "Not empty: directory name"
} ""

CCTK_STRING out3D_dir "Name of 3D ASCII output directory, overrides IO::out_dir" STEERABLE = ALWAYS
{
  "^$" :: "Empty: use IO::out_dir"
  ".+" :: "Not empty: directory name"
} ""



CCTK_STRING out0D_vars "Variables to output in 0D ASCII file format" STEERABLE = ALWAYS
{
  "" :: "List of group or variable names"
} ""

CCTK_STRING out1D_vars "Variables to output in 1D ASCII file format" STEERABLE = ALWAYS
{
  "" :: "List of group or variable names"
} ""

CCTK_STRING out2D_vars "Variables to output in 2D ASCII file format" STEERABLE = ALWAYS
{
  "" :: "List of group or variable names"
} ""

CCTK_STRING out3D_vars "Variables to output in 3D ASCII file format" STEERABLE = ALWAYS
{
  "" :: "List of group or variable names"
} ""



KEYWORD out0D_criterion "Criterion to select 0D ASCII output intervals, overrides out_every" STEERABLE = ALWAYS
{
  "default"   :: "Use IO::out_criterion"
  "never"     :: "Never output"
  "iteration" :: "Output every so many iterations"
  "divisor"   :: "Output if iteration mod divisor == 0."
  "time"      :: "Output every that much coordinate time"
} "default"

KEYWORD out1D_criterion "Criterion to select 1D ASCII output intervals, overrides out_every" STEERABLE = ALWAYS
{
  "default"   :: "Use IO::out_criterion"
  "never"     :: "Never output"
  "iteration" :: "Output every so many iterations"
  "divisor"   :: "Output if (iteration % out_every) == 0."
  "time"      :: "Output every that much coordinate time"
} "default"

KEYWORD out2D_criterion "Criterion to select 2D ASCII output intervals, overrides out_every" STEERABLE = ALWAYS
{
  "default"   :: "Use IO::out_criterion"
  "never"     :: "Never output"
  "iteration" :: "Output every so many iterations"
  "divisor"   :: "Output if (iteration % out_every) == 0."
  "time"      :: "Output every that much coordinate time"
} "default"

KEYWORD out3D_criterion "Criterion to select 3D ASCII output intervals, overrides out_every" STEERABLE = ALWAYS
{
  "default"   :: "Use IO::out_criterion"
  "never"     :: "Never output"
  "iteration" :: "Output every so many iterations"
  "divisor"   :: "Output if (iteration % out_every) == 0."
  "time"      :: "Output every that much coordinate time"
} "default"



CCTK_INT out0D_every "How often to do 0D ASCII output, overrides out_every" STEERABLE = ALWAYS
{
  1:*  :: "Output every so many time steps"
  -1:0 :: "No output"
  -2   :: "Use IO::out_every"
} -2

CCTK_INT out1D_every "How often to do 1D ASCII output, overrides out_every" STEERABLE = ALWAYS
{
  1:*  :: "Output every so many time steps"
  -1:0 :: "No output"
  -2   :: "Use IO::out_every"
} -2

CCTK_INT out2D_every "How often to do 2D ASCII output, overrides out_every" STEERABLE = ALWAYS
{
  1:*  :: "Output every so many time steps"
  -1:0 :: "No output"
  -2   :: "Use IO::out_every"
} -2

CCTK_INT out3D_every "How often to do 3D ASCII output, overrides out_every" STEERABLE = ALWAYS
{
  1:*  :: "Output every so many time steps"
  -1:0 :: "No output"
  -2   :: "Use IO::out_every"
} -2



REAL out0D_dt "How often to do 0D ASCII output, overrides IO::out_dt" STEERABLE = ALWAYS
{
  (0:* :: "In intervals of that much coordinate time"
   0   :: "As often as possible"
  -1   :: "Disable output"
  -2   :: "Default to IO::out_dt"
} -2

REAL out1D_dt "How often to do 1D ASCII output, overrides IO::out_dt" STEERABLE = ALWAYS
{
  (0:* :: "In intervals of that much coordinate time"
   0   :: "As often as possible"
  -1   :: "Disable output"
  -2   :: "Default to IO::out_dt"
} -2

REAL out2D_dt "How often to do 2D ASCII output, overrides IO::out_dt" STEERABLE = ALWAYS
{
  (0:* :: "In intervals of that much coordinate time"
   0   :: "As often as possible"
  -1   :: "Disable output"
  -2   :: "Default to IO::out_dt"
} -2

REAL out3D_dt "How often to do 3D ASCII output, overrides IO::out_dt" STEERABLE = ALWAYS
{
  (0:* :: "In intervals of that much coordinate time"
   0   :: "As often as possible"
  -1   :: "Disable output"
  -2   :: "Default to IO::out_dt"
} -2



CCTK_INT out0D_point_xi "x-index (counting from 0) for 0D points" STEERABLE = ALWAYS
{
  0:* :: ""
} 0
CCTK_INT out0D_point_yi "y-index (counting from 0) for 0D points" STEERABLE = ALWAYS
{
  0:* :: ""
} 0
CCTK_INT out0D_point_zi "z-index (counting from 0) for 0D points" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_REAL out0D_point_x "x coordinate for 0D points" STEERABLE = ALWAYS
{
  *:* :: ""
} 0
CCTK_REAL out0D_point_y "y coordinate for 0D points" STEERABLE = ALWAYS
{
  *:* :: ""
} 0
CCTK_REAL out0D_point_z "z coordinate for 0D points" STEERABLE = ALWAYS
{
  *:* :: ""
} 0



BOOLEAN out1D_x "Do 1D IOASCII output in the x-direction" STEERABLE = ALWAYS
{
} "yes"
BOOLEAN out1D_y "Do 1D IOASCII output in the y-direction" STEERABLE = ALWAYS
{
} "yes"
BOOLEAN out1D_z "Do 1D IOASCII output in the z-direction" STEERABLE = ALWAYS
{
} "yes"

CCTK_INT out1D_xline_yi "y-index (counting from 0) for 1D lines in x-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0
CCTK_INT out1D_xline_zi "z-index (counting from 0) for 1D lines in x-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_INT out1D_yline_xi "x-index (counting from 0) for 1D lines in y-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0
CCTK_INT out1D_yline_zi "z-index (counting from 0) for 1D lines in y-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_INT out1D_zline_xi "x-index (counting from 0) for 1D lines in z-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0
CCTK_INT out1D_zline_yi "y-index (counting from 0) for 1D lines in z-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_REAL out1D_xline_y "y coordinate for 1D lines in x-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0
CCTK_REAL out1D_xline_z "z coordinate for 1D lines in x-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0

CCTK_REAL out1D_yline_x "x coordinate for 1D lines in y-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0
CCTK_REAL out1D_yline_z "z coordinate for 1D lines in y-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0

CCTK_REAL out1D_zline_x "x coordinate for 1D lines in z-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0
CCTK_REAL out1D_zline_y "y coordinate for 1D lines in z-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0



BOOLEAN out2D_xy "Do 2D IOASCII output in the xy-direction" STEERABLE = ALWAYS
{
} "yes"
BOOLEAN out2D_xz "Do 2D IOASCII output in the xz-direction" STEERABLE = ALWAYS
{
} "yes"
BOOLEAN out2D_yz "Do 2D IOASCII output in the yz-direction" STEERABLE = ALWAYS
{
} "yes"

CCTK_INT out2D_xyplane_zi "z-index (counting from 0) for 2D planes in xy-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_INT out2D_xzplane_yi "y-index (counting from 0) for 2D planes in xz-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_INT out2D_yzplane_xi "x-index (counting from 0) for 2D planes in yz-direction" STEERABLE = ALWAYS
{
  0:* :: ""
} 0

CCTK_REAL out2D_xyplane_z "z coordinate for 2D planes in xy-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0

CCTK_REAL out2D_xzplane_y "y coordinate for 2D planes in xz-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0

CCTK_REAL out2D_yzplane_x "x coordinate for 2D planes in yz-direction" STEERABLE = ALWAYS
{
  *:* :: ""
} 0



BOOLEAN output_symmetry_points "Output symmetry points (assuming that there are nghostzones symmetry points)" STEERABLE = ALWAYS
{
} "yes"

BOOLEAN output_ghost_points "Output ghost points" STEERABLE = ALWAYS
{
} "yes"

BOOLEAN output_boundary_points "Output outer boundary points (assuming that there are nghostzones boundary points)" STEERABLE = ALWAYS
{
} "yes"

BOOLEAN out3D_ghosts "Output ghost zones (DEPRECATED)" STEERABLE = ALWAYS
{
} "yes"

BOOLEAN out3D_outer_ghosts "Output outer boundary zones (assuming that there are nghostzones boundary points) (DEPRECATED)" STEERABLE = ALWAYS
{
} "yes"



# These parameters are here for historic reasons only.
# They might go away in the future.  Do not use them.

BOOLEAN out1D_d "Do output along the diagonal" STEERABLE = ALWAYS
{
} "yes"

configuration: # Configuration definitions for thorn CarpetIOASCII

REQUIRES Carpet CarpetLib IOUtil

OPTIONAL SDF
{
}

context: make.configuration.defn:
```
# Main make.configuration.defn file for thorn CarpetIOASCII

ALL_UTILS += carpet2xgraph

ifneq ($(strip $(HAVE_SDF)), )
  ALL_UTILS += carpet2sdf
endif

```

make.configuration.deps:
```
# Main make.configuration.deps file for thorn CarpetIOASCII

CARPETIOASCII_BUILD_DIR = $(BUILD_DIR)/CarpetIOASCII
CARPETIOASCII_SRC_DIR   = $(PACKAGE_DIR)/Carpet/CarpetIOASCII/src/util

CARPETIOASCII_CFLAGS  = -DCCODE $(CFLAGS)
CARPETIOASCII_LDFLAGS = $(DEBUG_LD) $(LDFLAGS) $(CXXFLAGS) $(EXTRAFLAGS) $(GENERAL_LIBRARIES)

# add includes
CARPETIOASCII_CFLAGS += -I$(CONFIG) -I$(BINDINGS_DIR)/include -I$(FLESH_DIR)/include



# Compile
$(CARPETIOASCII_BUILD_DIR)/%.o: $(CARPETIOASCII_SRC_DIR)/%.c
	@echo "Compiling $<"
	-$(MKDIR) $(MKDIRFLAGS) $(CARPETIOASCII_BUILD_DIR) 2> /dev/null
	$(CC) $< $(CARPETIOASCII_CFLAGS) -c -o $@

# Link
$(UTIL_DIR)/%: $(CARPETIOASCII_BUILD_DIR)/%.o
	@echo "Creating $* in $(UTIL_DIR) from $<"
	-$(MKDIR) $(MKDIRFLAGS) $(UTIL_DIR) 2> /dev/null
	$(LD) $< $(CARPETIOASCII_LDFLAGS) -o $@



# Special versions for carpet2sdf:

# Compile
$(CARPETIOASCII_BUILD_DIR)/carpet2sdf.o: $(CARPETIOASCII_SRC_DIR)/carpet2sdf.c
	@echo "Compiling carpet2sdf"
	-$(MKDIR) $(MKDIRFLAGS) $(CARPETIOASCII_BUILD_DIR) 2> /dev/null
	$(CC) $< $(CARPETIOASCII_CFLAGS) $(INC_DIRS:%=-I%) -c -o $@

# Link
$(UTIL_DIR)/carpet2sdf: $(CARPETIOASCII_BUILD_DIR)/carpet2sdf.o
	@echo "Creating $* in $(UTIL_DIR) from $<"
	-$(MKDIR) $(MKDIRFLAGS) $(UTIL_DIR) 2> /dev/null
	$(LD) $< $(CARPETIOASCII_LDFLAGS) $(GENERAL_LIBRARIES) -o $@

```

make.code.defn:
```
# Main make.code.defn file for thorn CarpetIOASCII

# Source files in this directory
SRCS = ioascii.cc

# Subdirectories containing source files
SUBDIRS = 


```

ioascii.cc:
```
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <algorithm>
#include <fstream>
#include <iomanip>
#include <map>
#include <ostream>
#include <sstream>
#include <string>
#include <vector>

#include <cctk.h>
#include <cctk_Parameters.h>
#include <util_Network.h>
#include <util_Table.h>

#include <Timer.hh>

#include "CactusBase/IOUtil/src/ioGH.h"
#include "CactusBase/IOUtil/src/ioutil_Utils.h"

#include "carpet.hh"

#include "typeprops.hh"

#include "ioascii.hh"

// That's a hack
namespace Carpet {
void UnsupportedVarType(const int vindex);
}

#define GetParameter(parameter)                                                \
  (outdim == 0 ? out0D_##parameter : outdim == 1                               \
                                         ? out1D_##parameter                   \
                                         : outdim == 2 ? out2D_##parameter     \
                                                       : out3D_##parameter)

namespace CarpetIOASCII {

using namespace std;
using namespace Carpet;

// Begin a new line without flushing the output buffer
const char *const eol = "\n";

// IO processor
const int ioproc = 0;

// Global configuration parameters
bool stop_on_parse_errors = false;

int CarpetIOASCIIStartup() {
  IOASCII<0>::Startup();
  IOASCII<1>::Startup();
  IOASCII<2>::Startup();
  IOASCII<3>::Startup();
  return 0;
}

void CarpetIOASCIIInit(CCTK_ARGUMENTS) {
  DECLARE_CCTK_ARGUMENTS;

  for (int d = 0; d < 4; ++d) {
    this_iteration[d] = 0;
    last_output_iteration[d] = 0;
    last_output_time[d] = cctk_time;
  }
}

// Definition of static members
template <int outdim> char *IOASCII<outdim>::my_out_dir;
template <int outdim> char *IOASCII<outdim>::my_out_vars;
template <int outdim> vector<ioRequest *> IOASCII<outdim>::requests;

template <int outdim> int IOASCII<outdim>::Startup() {
  ostringstream msg;
  msg << "AMR " << outdim << "D ASCII I/O provided by CarpetIOASCII";
  CCTK_RegisterBanner(msg.str().c_str());

  ostringstream extension_name;
  extension_name << "CarpetIOASCII_" << outdim << "D";
  const int GHExtension =
      CCTK_RegisterGHExtension(extension_name.str().c_str());
  CCTK_RegisterGHExtensionSetupGH(GHExtension, SetupGH);

  ostringstream method_name;
  method_name << "IOASCII_" << outdim << "D";
  const int IOMethod = CCTK_RegisterIOMethod(method_name.str().c_str());
  CCTK_RegisterIOMethodOutputGH(IOMethod, OutputGH);
  CCTK_RegisterIOMethodOutputVarAs(IOMethod, OutputVarAs);
  CCTK_RegisterIOMethodTimeToOutput(IOMethod, TimeToOutput);
  CCTK_RegisterIOMethodTriggerOutput(IOMethod, TriggerOutput);

  return 0;
}

template <int outdim>
void *IOASCII<outdim>::SetupGH(tFleshConfig *const fc, const int convLevel,
                               cGH *const cctkGH) {
  DECLARE_CCTK_PARAMETERS;
  const void *dummy;

  dummy = &fc;
  dummy = &convLevel;
  dummy = &cctkGH;
  dummy = &dummy;

  if (not CCTK_Equals(verbose, "none")) {
    CCTK_VInfo(CCTK_THORNSTRING,
               "I/O Method 'IOASCII_%dD' registered: "
               "%dD AMR output of grid variables to ASCII files",
               outdim, outdim);
  }

  const int numvars = CCTK_NumVars();
  requests.resize(numvars);

  // initial I/O parameter check
  my_out_dir = 0;
  my_out_vars = strdup("");
  stop_on_parse_errors = strict_io_parameter_check != 0;
  CheckSteerableParameters(cctkGH);
  stop_on_parse_errors = false;

  // We register only once, ergo we get only one handle.  We store
  // that statically, so there is no need to pass anything to
  // Cactus.
  return NULL;
}

template <int outdim>
void IOASCII<outdim>::CheckSteerableParameters(const cGH *const cctkGH) {
  DECLARE_CCTK_PARAMETERS;

  // re-parse the 'IOASCII::out%dD_dir' parameter if it has changed
  const char *the_out_dir = GetParameter(dir);
  if (CCTK_EQUALS(the_out_dir, "")) {
    the_out_dir = out_dir;
  }

  if (not my_out_dir or strcmp(the_out_dir, my_out_dir)) {
    free(my_out_dir);
    my_out_dir = strdup(the_out_dir);

    // create the output directory
    const int result = IOUtil_CreateDirectory(cctkGH, my_out_dir, 0, 0);
    if (result < 0) {
      CCTK_VWarn(CCTK_WARN_ALERT, __LINE__, __FILE__, CCTK_THORNSTRING,
                 "Problem creating %dD-output directory '%s'", outdim,
                 my_out_dir);
    } else if (result > 0 and CCTK_Equals(verbose, "full")) {
      CCTK_VInfo(CCTK_THORNSTRING, "%dD-output directory '%s' already exists",
                 outdim, my_out_dir);
    }
  }

  // re-parse the 'IOASCII::out%d_vars' parameter if it has changed
  const char *const out_vars = GetParameter(vars);
  if (strcmp(out_vars, my_out_vars)) {
    ostringstream parameter_name;
    parameter_name << "IOASCII::out" << outdim << "D_vars";
#ifdef IOUTIL_PARSER_HAS_OUT_DT
    IOUtil_ParseVarsForOutput(
        cctkGH, CCTK_THORNSTRING, parameter_name.str().c_str(),
        stop_on_parse_errors, out_vars, -1, -1.0, &requests[0]);
#else
    IOUtil_ParseVarsForOutput(cctkGH, CCTK_THORNSTRING,
                              parameter_name.str().c_str(),
                              stop_on_parse_errors, out_vars, -1, &requests[0]);
#endif

    // notify the user about the new setting
    if (not CCTK_Equals(verbose, "none")) {
      int count = 0;
      ostringstream msg;
      msg << "Periodic " << outdim << "D AMR output requested for:";
      for (int vi = 0; vi < CCTK_NumVars(); ++vi) {
        if (requests.at(vi)) {
          ++count;
          char *const fullname = CCTK_FullName(vi);
          msg << eol << "   " << fullname;
          free(fullname);
        }
      }
      if (count > 0) {
        CCTK_INFO(msg.str().c_str());
      }
    }

    // save the last setting of 'IOASCII::out%d_vars' parameter
    free(my_out_vars);
    my_out_vars = strdup(out_vars);
  }
}

template <int outdim> int IOASCII<outdim>::OutputGH(const cGH *const cctkGH) {
  DECLARE_CCTK_PARAMETERS;

  ostringstream timer_name;
  timer_name << "OutputGH<" << outdim << ">";
  Timers::Timer timer(timer_name.str());

  timer.start();
  CheckSteerableParameters(cctkGH);
  if (strcmp(my_out_vars, "")) {
    for (int vi = 0; vi < CCTK_NumVars(); ++vi) {
      if (TimeToOutput(cctkGH, vi)) {
        TriggerOutput(cctkGH, vi);
      }
    }
  }
  timer.stop();

  return 0;
}

template <int outdim>
int IOASCII<outdim>::TimeToOutput(const cGH *const cctkGH, const int vindex) {
  DECLARE_CCTK_ARGUMENTS;
  DECLARE_CCTK_PARAMETERS;

  assert(vindex >= 0 and vindex < CCTK_NumVars());

  if (CCTK_GroupTypeFromVarI(vindex) != CCTK_GF and not do_global_mode) {
    return 0;
  }

  // check if output for this variable was requested
  if (not requests.at(vindex)) {
    return 0;
  }

  // check whether this refinement level should be output
  if (not(requests.at(vindex)->refinement_levels & (1 << reflevel))) {
    return 0;
  }

  // check if output for this variable was requested individually by
  // a "<varname>{ out_every = <number> }" option string
  // this will overwrite the output criterion setting
  const char *myoutcriterion = GetParameter(criterion);
  if (CCTK_EQUALS(myoutcriterion, "default")) {
    myoutcriterion = out_criterion;
  }
  if (requests.at(vindex)->out_every >= 0) {
    myoutcriterion = "divisor";
  }

  if (CCTK_EQUALS(myoutcriterion, "never")) {
    return 0;
  }

  // check whether to output at this iteration
  bool output_this_iteration = false;

  if (CCTK_EQUALS(myoutcriterion, "iteration")) {
    int myoutevery = GetParameter(every);
    if (myoutevery == -2) {
      myoutevery = out_every;
    }
    if (myoutevery > 0) {
      if (cctk_iteration == this_iteration[outdim]) {
        // we already decided to output this iteration
        output_this_iteration = true;
      } else if (cctk_iteration >= last_output_iteration[outdim] + myoutevery) {
        // it is time for the next output
        output_this_iteration = true;
        last_output_iteration[outdim] = cctk_iteration;
        this_iteration[outdim] = cctk_iteration;
      }
    }
  } else if (CCTK_EQUALS(myoutcriterion, "divisor")) {
    int myoutevery = GetParameter(every);
    if (myoutevery == -2) {
      myoutevery = out_every;
    }
    if (requests[vindex]->out_every >= 0) {
      myoutevery = requests[vindex]->out_every;
    }
    if (myoutevery > 0 and (cctk_iteration % myoutevery) == 0) {
      // we already decided to output this iteration
      output_this_iteration = true;
    }
  } else if (CCTK_EQUALS(myoutcriterion, "time")) {
    CCTK_REAL myoutdt = GetParameter(dt);
    if (myoutdt == -2) {
      myoutdt = out_dt;
    }
    if (myoutdt == 0 or cctk_iteration == this_iteration[outdim]) {
      output_this_iteration = true;
    } else if (myoutdt > 0) {
      int do_output =
          cctk_time / cctk_delta_time >=
          (last_output_time[outdim] + myoutdt) / cctk_delta_time - 1.0e-12;
      MPI_Bcast(&do_output, 1, MPI_INT, 0, dist::comm());
      if (do_output) {
        // it is time for the next output
        output_this_iteration = true;
        last_output_time[outdim] = cctk_time;
        this_iteration[outdim] = cctk_iteration;
      }
    }
  } // select output criterion

  return output_this_iteration ? 1 : 0;
}

template <int outdim>
int IOASCII<outdim>::TriggerOutput(const cGH *const cctkGH, const int vindex) {
  DECLARE_CCTK_PARAMETERS;

  assert(vindex >= 0 and vindex < CCTK_NumVars());

  char *const fullname = CCTK_FullName(vindex);

  int retval;
  if (one_file_per_group) {
    char *const alias_c = CCTK_GroupNameFromVarI(vindex);
    string alias(alias_c);
    free(alias_c);
    transform(alias.begin(), alias.end(), alias.begin(), ::tolower);
    string const oldsep("::");
    size_t const oldseppos = alias.find(oldsep);
    assert(oldseppos != string::npos);
    alias.replace(oldseppos, oldsep.size(), out_group_separator);
    retval = OutputVarAs(cctkGH, fullname, alias.c_str());
  } else {
    const char *const alias = CCTK_VarName(vindex);
    retval = OutputVarAs(cctkGH, fullname, alias);
  }

  free(fullname);

  return retval;
}

static void GetVarIndex(const int vindex, const char *const optstring,
                        void *const arg) {
  if (optstring) {
    char *const fullname = CCTK_FullName(vindex);
    CCTK_VWarn(CCTK_WARN_COMPLAIN, __LINE__, __FILE__, CCTK_THORNSTRING,
               "Option string '%s' will be ignored for ASCII output of "
               "variable '%s'",
               optstring, fullname);
    free(fullname);
  }

  *static_cast<int *>(arg) = vindex;
}

template <int outdim>
int IOASCII<outdim>::OutputVarAs(const cGH *const cctkGH,
                                 const char *const varname,
                                 const char *const alias) {
  DECLARE_CCTK_PARAMETERS;

  int vindex = -1;

  if (CCTK_TraverseString(varname, GetVarIndex, &vindex, CCTK_VAR) < 0) {
    CCTK_VWarn(CCTK_WARN_ALERT, __LINE__, __FILE__, CCTK_THORNSTRING,
               "error while parsing variable name '%s' (alias name '%s')",
               varname, alias);
    return -1;
  }

  if (vindex < 0) {
    return -1;
  }

  if (not(is_level_mode() or (is_singlemap_mode() and maps == 1) or
          (is_local_mode() and maps == 1 and
           vhh.at(Carpet::map)->local_components(reflevel) == 1))) {
    CCTK_WARN(CCTK_WARN_ALERT, "OutputVarAs must be called in level mode");
    return -1;
  }

  BEGIN_LEVEL_MODE(cctkGH) {

    // Get information
    const int group = CCTK_GroupIndexFromVarI(vindex);
    assert(group >= 0);
    cGroup groupdata;
    {
      int const ierr = CCTK_GroupData(group, &groupdata);
      assert(not ierr);
    }

    // Check information
    if (groupdata.grouptype != CCTK_GF) {
      assert(do_global_mode);
    }

    if (outdim > groupdata.dim) {
      CCTK_VWarn(CCTK_WARN_ALERT, __LINE__, __FILE__, CCTK_THORNSTRING,
                 "Cannot produce %dD ASCII output file '%s' for variable '%s' "
                 "because it has only %d dimensions",
                 outdim, alias, varname, groupdata.dim);
      return -1;
    }

    // Check for storage
    if (not CCTK_QueryGroupStorageI(cctkGH, group)) {
      // This may be okay if storage is e.g. scheduled only in the
      // analysis bin
      CCTK_VWarn(CCTK_WARN_DEBUG, __LINE__, __FILE__, CCTK_THORNSTRING,
                 "Cannot output variable '%s' because it has no storage",
                 varname);
      return 0;
    }

    ostringstream basefilenamebuf;
    basefilenamebuf << my_out_dir << "/" << alias;
    const string basefilename = basefilenamebuf.str();

    // Check if the file has been created already
    bool is_new_file, truncate_file;
    const bool did_output =
        DidOutput(cctkGH, vindex, basefilename, is_new_file, truncate_file);
    if (did_output) {
      return 0;
    }

    // Loop over all direction combinations
    vect<int, outdim> dirs(0);
    bool done;
    do {

      // Output each combination only once
      bool ascending = true;
      for (int d1 = 0; d1 < outdim; ++d1) {
        for (int d2 = d1 + 1; d2 < outdim; ++d2) {
          ascending = ascending and dirs[d1] < dirs[d2];
        }
      }

      // Skip output if the dimensions are not ascending
      if (ascending) {

        // Skip output if not requested
        if (DirectionIsRequested(dirs)) {
          OutputDirection(cctkGH, vindex, alias, basefilename, dirs,
                          is_new_file, truncate_file);
        }

      } // if ascending

      // Next direction combination
      done = true;
      for (int d = 0; d < outdim; ++d) {
        ++dirs[d];
        if (dirs[d] < groupdata.dim + (outdim == 1 ? 1 : 0)) {
          done = false;
          break;
        }
        dirs[d] = 0;
      }

    } while (not done); // output all directions
  }
  END_LEVEL_MODE;

  return 0;
}

// Traverse all maps and components on this refinement and multigrid
// level
template <int outdim>
void IOASCII<outdim>::OutputDirection(const cGH *const cctkGH, const int vindex,
                                      const string alias,
                                      const string basefilename,
                                      const vect<int, outdim> &dirs,
                                      const bool is_new_file,
                                      const bool truncate_file) {
  DECLARE_CCTK_PARAMETERS;

  // Get information
  const int group = CCTK_GroupIndexFromVarI(vindex);
  assert(group >= 0);
  const int vindex0 = CCTK_FirstVarIndexI(group);
  assert(vindex0 >= 0 and vindex >= vindex0);
  const int var = vindex - vindex0;
  cGroup groupdata;
  {
    int const ierr = CCTK_GroupData(group, &groupdata);
    assert(not ierr);
  }

  const int ml = groupdata.grouptype == CCTK_GF ? mglevel : 0;
  const int rl = groupdata.grouptype == CCTK_GF ? reflevel : 0;

  // const int num_tl = CCTK_NumTimeLevelsFromVarI (vindex);
  const int num_tl = CCTK_ActiveTimeLevelsVI(cctkGH, vindex);
  assert(num_tl >= 1);

  int const coord_group = CCTK_GroupIndex("grid::coordinates");

  // Loop over all maps
  const int m_min = 0;
  const int m_max = groupdata.grouptype == CCTK_GF ? Carpet::maps : 1;
  for (int m = m_min; m < m_max; ++m) {

    fstream file;
    OpenFile(cctkGH, m, vindex, alias, basefilename, dirs, is_new_file,
             truncate_file, file);

    // Find the output offset
    const ivect offset =
        groupdata.grouptype == CCTK_GF ? GetOutputOffset(cctkGH, m, dirs) : 0;

    const gh *const hh = arrdata.at(group).at(m).hh;
    const dh *const dd = arrdata.at(group).at(m).dd;

    // Traverse all components on this multigrid level, refinement
    // level, and map
    const int c_min = 0;
    const int c_max = groupdata.grouptype == CCTK_GF
                          ? hh->components(reflevel)
                          : groupdata.disttype != CCTK_DISTRIB_CONSTANT
                                ? CCTK_nProcs(cctkGH)
                                : 1;
    for (int c = c_min; c < c_max; ++c) {
      int const lc = hh->get_local_component(rl, c);
      int const proc = hh->processor(rl, c);
      if (dist::rank() == proc or dist::rank() == ioproc) {

        const ibbox &data_ext = dd->light_boxes.at(ml).at(rl).at(c).exterior;
        const ibbox ext = GetOutputBBox(cctkGH, group, rl, m, c, data_ext);

        CCTK_REAL coord_time;
        rvect coord_lower, coord_upper;
        GetCoordinates(cctkGH, m, groupdata, ext, coord_time, coord_lower,
                       coord_upper);

        // Apply offset
        ivect offset1;
        if (groupdata.grouptype == CCTK_GF) {
          const ibbox &baseext = hh->baseextents.at(ml).at(rl);
          offset1 = baseext.lower() + offset * ext.stride();
        } else {
          offset1 = offset * ext.stride();
        }
        for (int d = 0; d < outdim; ++d) {
          if (dirs[d] < 3) {
            offset1[dirs[d]] = ext.lower()[dirs[d]];
          }
        }

        const int tl_min = 0;
        const int tl_max = output_all_timelevels ? num_tl : 1;
        for (int tl = tl_min; tl < tl_max; ++tl) {

          mempool pool;

          const int n_min = one_file_per_group ? 0 : var;
          const int n_max =
              one_file_per_group ? CCTK_NumVarsInGroupI(group) : var + 1;
          vector<const gdata *> datas(n_max - n_min);
          for (size_t n = 0; n < datas.size(); ++n) {
            if (dist::rank() == proc) {
              const ggf *const ff = arrdata.at(group).at(m).data.at(n + n_min);
              datas.at(n) = ff->data_pointer(tl, rl, lc, ml);
            } else {
              datas.at(n) = NULL;
            }
          }

          vector<const gdata *> coords;
          if (use_grid_coordinates and groupdata.grouptype == CCTK_GF) {
            coords.resize(dim);
            for (int d = 0; d < dim; ++d) {
              if (dist::rank() == proc) {
                const ggf *const ff = arrdata.at(coord_group).at(m).data.at(d);
                coords.at(d) = ff->data_pointer(0, rl, lc, ml);
              } else {
                coords.at(d) = NULL;
              }
            }
          }

          vector<gdata *> tmpdatas(datas.size());
          vector<gdata *> tmpcoords(coords.size());

          if (proc != ioproc) {

            for (size_t n = 0; n < datas.size(); ++n) {
              const ggf *const ff = arrdata.at(group).at(m).data.at(n + n_min);
              tmpdatas.at(n) = ff->new_typed_data();
              size_t const memsize =
                  tmpdatas.at(n)->allocsize(data_ext, ioproc);
              void *const memptr = pool.alloc(memsize);
              tmpdatas.at(n)->allocate(data_ext, ioproc, memptr, memsize);
            } // for n
            for (size_t n = 0; n < coords.size(); ++n) {
              const ggf *const ff = arrdata.at(coord_group).at(m).data.at(n);
              tmpcoords.at(n) = ff->new_typed_data();
              size_t const memsize =
                  tmpcoords.at(n)->allocsize(data_ext, ioproc);
              void *const memptr = pool.alloc(memsize);
              tmpcoords.at(n)->allocate(data_ext, ioproc, memptr, memsize);
            } // for n

            for (comm_state state; not state.done(); state.step()) {
              for (size_t n = 0; n < datas.size(); ++n) {
                tmpdatas.at(n)->copy_from(state, datas.at(n), data_ext,
                                          data_ext, NULL, ioproc, proc);
              }
              for (size_t n = 0; n < coords.size(); ++n) {
                tmpcoords.at(n)->copy_from(state, coords.at(n), data_ext,
                                           data_ext, NULL, ioproc, proc);
              }
            }

          } else {

            for (size_t n = 0; n < datas.size(); ++n) {
              tmpdatas.at(n) = const_cast<gdata *>(datas.at(n));
            }
            for (size_t n = 0; n < coords.size(); ++n) {
              tmpcoords.at(n) = const_cast<gdata *>(coords.at(n));
            }
          }

          if (dist::rank() == ioproc) {
            WriteASCII(file, tmpdatas, ext, vindex, cctkGH->cctk_iteration,
                       offset1, dirs, rl, ml, m, c, tl, coord_time, coord_lower,
                       coord_upper, tmpcoords);
          }

          if (proc != ioproc) {
            for (size_t n = 0; n < tmpdatas.size(); ++n) {
              delete tmpdatas.at(n);
            }
            for (size_t n = 0; n < tmpcoords.size(); ++n) {
              delete tmpcoords.at(n);
            }
          }

          // Append EOL after every component
          if (dist::rank() == ioproc) {
            if (separate_components) {
              assert(file.good());
              file << eol;
            }
            assert(file.good());
          }

        } // for tl
      }
    } // for c

    // Append EOL after every complete set of components
    if (dist::rank() == ioproc) {
      if (separate_grids and not compact_format) {
        assert(file.good());
        file << eol;
      }
      assert(file.good());
    }

    CloseFile(cctkGH, file);

  } // for m
}

template <int outdim>
bool IOASCII<outdim>::DidOutput(const cGH *const cctkGH, const int vindex,
                                const string basefilename, bool &is_new_file,
                                bool &truncate_file) {
  DECLARE_CCTK_PARAMETERS;

  typedef std::map<string, vector<vector<vector<int> > > > filelist;
  static filelist created_files;

  filelist::iterator thisfile = created_files.find(basefilename);
  is_new_file = thisfile == created_files.end();
  truncate_file = is_new_file and IO_TruncateOutputFiles(cctkGH);

  if (is_new_file) {
    const int numelems = one_file_per_group ? CCTK_NumGroups() : CCTK_NumVars();
    vector<vector<vector<int> > > last_outputs; // [ml][rl][var]
    last_outputs.resize(mglevels);
    for (int ml = 0; ml < mglevels; ++ml) {
      last_outputs.at(ml).resize(maxreflevels);
      for (int rl = 0; rl < maxreflevels; ++rl) {
        last_outputs.at(ml).at(rl).resize(numelems, cctkGH->cctk_iteration - 1);
      }
    }
    // TODO: this makes a copy of last_outputs, which is expensive;
    // change this to use a reference instead
    thisfile = created_files.insert(
        thisfile, filelist::value_type(basefilename, last_outputs));
    assert(thisfile != created_files.end());
  }

  // Check if this variable has been output already during this
  // iteration
  const int elem =
      one_file_per_group ? CCTK_GroupIndexFromVarI(vindex) : vindex;
  int &last_output = thisfile->second.at(mglevel).at(reflevel).at(elem);
  if (last_output == cctkGH->cctk_iteration) {
    // has already been output during this iteration
    char *const fullname = CCTK_FullName(vindex);
    CCTK_VWarn(5, __LINE__, __FILE__, CCTK_THORNSTRING,
               "Skipping output for variable '%s', because this variable "
               "has already been output during the current iteration -- "
               "probably via a trigger during the analysis stage",
               fullname);
    free(fullname);
    return true;
  }
  assert(last_output < cctkGH->cctk_iteration);
  last_output = cctkGH->cctk_iteration;

  return false;
}

CCTK_REAL io_files;
CCTK_REAL io_bytes_begin, io_bytes_end;

template <int outdim>
void IOASCII<outdim>::OpenFile(const cGH *const cctkGH, const int m,
                               const int vindex, const string alias,
                               const string basefilename,
                               const vect<int, outdim> &dirs,
                               const bool is_new_file, const bool truncate_file,
                               fstream &file) {
  DECLARE_CCTK_PARAMETERS;

  BeginTimingIO(cctkGH);
  io_files = 0;
  io_bytes_begin = 0;
  io_bytes_end = 0;

  if (dist::rank() == ioproc) {

    const int grouptype = CCTK_GroupTypeFromVarI(vindex);
    assert(grouptype >= 0);

    // Invent a file name
    ostringstream filenamebuf;
    filenamebuf << basefilename;
    if (maps > 1 and grouptype == CCTK_GF) {
      filenamebuf << "." << m;
    }
    filenamebuf << ".";
    if (new_filename_scheme) {
      for (int d = 0; d < outdim; ++d) {
        const char *const coords = "xyzd";
        filenamebuf << coords[dirs[d]];
      }
      filenamebuf << ".asc";
    } else {
      for (int d = 0; d < outdim; ++d) {
        assert(dirs[d] >= 0 and dirs[d] < 4);
        const char *const coords = "xyzd";
        filenamebuf << coords[dirs[d]];
      }
      const char *const suffixes = "plpv";
      filenamebuf << suffixes[outdim];
    }
    // we need a persistent temporary here
    const string filenamestr = filenamebuf.str();
    const char *const filename = filenamestr.c_str();

    // Open the file
    file.open(filename, ios::out | (truncate_file ? ios::trunc : ios::app));
    if (not file.good()) {
      char *const fullname = CCTK_FullName(vindex);
      CCTK_VError(__LINE__, __FILE__, CCTK_THORNSTRING,
                  "Could not open output file '%s' for variable '%s'", filename,
                  fullname);
      free(fullname);
    }
    io_files += 1;
    io_bytes_begin = file.tellg();

    // If this is the first time, then write a nice header
    if (is_new_file) {

      bool want_labels = false;
      bool want_date = false;
      bool want_parfilename = false;
      bool want_other = false;
      if (CCTK_EQUALS(out_fileinfo, "none")) {
        // do nothing
      } else if (CCTK_EQUALS(out_fileinfo, "axis labels")) {
        want_labels = true;
      } else if (CCTK_EQUALS(out_fileinfo, "creation date")) {
        want_date = true;
      } else if (CCTK_EQUALS(out_fileinfo, "parameter filename")) {
        want_parfilename = true;
      } else if (CCTK_EQUALS(out_fileinfo, "all")) {
        want_labels = true;
        want_date = true;
        want_parfilename = true;
        want_other = true;
      } else {
        CCTK_ERROR("internal error");
      }

      file << "# " << outdim << "D ASCII output created by CarpetIOASCII"
           << eol;

      if (want_date) {
        char run_host[1000];
        Util_GetHostName(run_host, sizeof run_host);
        const char *run_user = getenv("USER");
        if (not run_user) {
          run_user = "";
        }
        char run_date[1000];
        Util_CurrentDate(sizeof run_date, run_date);
        char run_time[1000];
        Util_CurrentTime(sizeof run_time, run_time);
        file << "# created on " << run_host << " by " << run_user << " on "
             << run_date << " at " << run_time << eol;
        assert(file.good());
      }

      if (want_parfilename) {
        char parameter_filename[10000];
        CCTK_ParameterFilename(sizeof parameter_filename, parameter_filename);
        file << "# parameter filename: \"" << parameter_filename << "\"" << eol;
      }

      if (want_other) {
        if (CCTK_IsFunctionAliased("UniqueBuildID")) {
          const char *const build_id = (const char *)UniqueBuildID(cctkGH);
          file << "# Build ID: " << build_id << eol;
        }
        if (CCTK_IsFunctionAliased("UniqueSimulationID")) {
          const char *const job_id = (const char *)UniqueSimulationID(cctkGH);
          file << "# Simulation ID: " << job_id << eol;
        }
        if (CCTK_IsFunctionAliased("UniqueRunID")) {
          const char *const job_id = (const char *)UniqueRunID(cctkGH);
          file << "# Run ID: " << job_id << eol;
        }
      }

      file << "#" << eol;

      if (want_labels) {
        if (one_file_per_group) {
          char *const groupname = CCTK_GroupNameFromVarI(vindex);
          file << "# " << groupname;
          free(groupname);
        } else {
          const char *const varname = CCTK_VarName(vindex);
          file << "# " << varname;
        }
        for (int d = 0; d < outdim; ++d) {
          file << " "
               << "xyzd"[dirs[d]];
        }
        file << " (" << alias << ")" << eol;
        file << "#" << eol;
      }

    } // if is_new_file

    file << setprecision(out_precision);
    assert(file.good());

  } // if on the I/O processor
}

template <int outdim>
void IOASCII<outdim>::CloseFile(const cGH *const cctkGH, fstream &file) {
  DECLARE_CCTK_PARAMETERS;

  if (dist::rank() == ioproc) {
    io_bytes_end = file.tellg();
    file.close();
    assert(file.good());
  }

  assert(not file.is_open());

  CCTK_REAL const io_bytes = io_bytes_end - io_bytes_begin;
  EndTimingIO(cctkGH, io_files, io_bytes, false);
}

// Check whether this output direction has been requested
template <int outdim>
bool IOASCII<outdim>::DirectionIsRequested(const vect<int, outdim> &dirs) {
  DECLARE_CCTK_PARAMETERS;

  switch (outdim) {

  case 0:
    // Output is always requested (if switched on)
    return true;

  case 1:
    switch (dirs[0]) {
    case 0:
      return out1D_x;
    case 1:
      return out1D_y;
    case 2:
      return out1D_z;
    case 3:
      return out1D_d;
    }
    assert(0);

  case 2:
    if (dirs[0] == 0 and dirs[1] == 1)
      return out2D_xy;
    if (dirs[0] == 0 and dirs[1] == 2)
      return out2D_xz;
    if (dirs[0] == 1 and dirs[1] == 2)
      return out2D_yz;
    assert(0);

  case 3:
    // Output is always requested (if switched on)
    return true;
  }
  assert(0);
}

// Get the region that should be output, in terms of grid points;
// this is the offset perpendicular to the output hyperslab
template <int outdim>
ivect IOASCII<outdim>::GetOutputOffset(const cGH *const cctkGH, const int m,
                                       const vect<int, outdim> &dirs) {
  DECLARE_CCTK_PARAMETERS;

  // Default is zero
  ivect offset(0);

  switch (outdim) {

  case 0:
    // 0D output
    offset[0] =
        GetGridOffset(cctkGH, m, 1, "out0D_point_xi", /*"out_point_xi"*/ NULL,
                      "out0D_point_x", /*"out_point_x"*/ NULL,
                      /*out_point_x*/ 0.0);
    offset[1] =
        GetGridOffset(cctkGH, m, 2, "out0D_point_yi", /*"out_point_yi"*/ NULL,
                      "out0D_point_y", /*"out_point_y"*/ NULL,
                      /*out_point_y*/ 0.0);
    offset[2] =
        GetGridOffset(cctkGH, m, 3, "out0D_point_zi", /*"out_point_zi"*/ NULL,
                      "out0D_point_z", /*"out_point_z"*/ NULL,
                      /*out_point_z*/ 0.0);
    break;

  case 1:
    // 1D output
    switch (dirs[0]) {
    case 0:
      offset[1] = GetGridOffset(cctkGH, m, 2, "out1D_xline_yi", "out_xline_yi",
                                "out1D_xline_y", "out_xline_y", out_xline_y);
      offset[2] = GetGridOffset(cctkGH, m, 3, "out1D_xline_zi", "out_xline_zi",
                                "out1D_xline_z", "out_xline_z", out_xline_z);
      break;
    case 1:
      offset[0] = GetGridOffset(cctkGH, m, 1, "out1D_yline_xi", "out_yline_xi",
                                "out1D_yline_x", "out_yline_x", out_yline_x);
      offset[2] = GetGridOffset(cctkGH, m, 3, "out1D_yline_zi", "out_yline_zi",
                                "out1D_yline_z", "out_yline_z", out_yline_z);
      break;
    case 2:
      offset[0] = GetGridOffset(cctkGH, m, 1, "out1D_zline_xi", "out_zline_xi",
                                "out1D_zline_x", "out_zline_x", out_zline_x);
      offset[1] = GetGridOffset(cctkGH, m, 2, "out1D_zline_yi", "out_zline_yi",
                                "out1D_zline_y", "out_zline_y", out_zline_y);
      break;
    case 3:
      // the diagonal: we don't care about the offset
      break;
    default:
      assert(0);
    }
    break;

  case 2:
    // 2D output
    if (dirs[0] == 0 and dirs[1] == 1) {
      offset[2] =
          GetGridOffset(cctkGH, m, 3, "out2D_xyplane_zi", "out_xyplane_zi",
                        "out2D_xyplane_z", "out_xyplane_z", out_xyplane_z);
    } else if (dirs[0] == 0 and dirs[1] == 2) {
      offset[1] =
          GetGridOffset(cctkGH, m, 2, "out2D_xzplane_yi", "out_xzplane_yi",
                        "out2D_xzplane_y", "out_xzplane_y", out_xzplane_y);
    } else if (dirs[0] == 1 and dirs[1] == 2) {
      offset[0] =
          GetGridOffset(cctkGH, m, 1, "out2D_yzplane_xi", "out_yzplane_xi",
                        "out2D_yzplane_x", "out_yzplane_x", out_yzplane_x);
    } else {
      assert(0);
    }
    break;

  case 3:
    // 3D output: the offset does not matter
    break;

  default:
    assert(0);
  }

  return offset;
}

// Omit symmetry and ghost zones if requested
ibbox GetOutputBBox(const cGH *const cctkGH, const int group, const int rl,
                    const int m, const int c, const ibbox &ext) {
  DECLARE_CCTK_PARAMETERS;

  const int groupdim = CCTK_GroupDimI(group);
  assert(groupdim >= 0);
  const int grouptype = CCTK_GroupTypeI(group);
  assert(grouptype >= 0);

  // TODO: This is a bit ad hoc
  CCTK_INT symtable;
  if (grouptype == CCTK_GF and groupdim == cctkGH->cctk_dim) {
    symtable = SymmetryTableHandleForGrid(cctkGH);
    if (symtable < 0)
      CCTK_ERROR("internal error");
  } else {
    symtable = SymmetryTableHandleForGI(cctkGH, group);
    if (symtable < 0)
      CCTK_ERROR("internal error");
  }

  CCTK_INT symbnd[2 * dim];
  int const ierr =
      Util_TableGetIntArray(symtable, 2 * groupdim, symbnd, "symmetry_handle");
  if (ierr != 2 * groupdim)
    CCTK_ERROR("internal error");

  bool is_symbnd[2 * dim];
  for (int d = 0; d < 2 * groupdim; ++d) {
    is_symbnd[d] = symbnd[d] >= 0;
  }

  ivect lo = ext.lower();
  ivect hi = ext.upper();
  const ivect str = ext.stride();

  const b2vect obnds = vhh.at(m)->outer_boundaries(rl, c);
  const i2vect ghost_width = arrdata.at(group).at(m).dd->ghost_widths.at(rl);

  for (int d = 0; d < groupdim; ++d) {
    bool const output_lower_ghosts =
        obnds[0][d] ? (is_symbnd[2 * d]
                           ? output_symmetry_points
                           : (output_boundary_points and out3D_outer_ghosts))
                    : (output_ghost_points and out3D_ghosts);
    bool const output_upper_ghosts =
        obnds[1][d] ? (is_symbnd[2 * d + 1]
                           ? output_symmetry_points
                           : (output_boundary_points and out3D_outer_ghosts))
                    : (output_ghost_points and out3D_ghosts);

    if (not output_lower_ghosts) {
      lo[d] += ghost_width[0][d] * str[d];
    }
    if (not output_upper_ghosts) {
      hi[d] -= ghost_width[1][d] * str[d];
    }
  }

  return ibbox(lo, hi, str);
}

// Determine coordinates
void GetCoordinates(const cGH *const cctkGH, const int m,
                    const cGroup &groupdata, const ibbox &ext,
                    CCTK_REAL &coord_time, rvect &coord_lower,
                    rvect &coord_upper) {
  coord_time = cctkGH->cctk_time;

  rvect global_lower;
  rvect coord_delta;
  if (groupdata.grouptype == CCTK_GF) {
    rvect const cctk_origin_space = origin_space.at(m).at(mglevel);
    rvect const cctk_delta_space = delta_space.at(m) * rvect(mglevelfact);
    for (int d = 0; d < dim; ++d) {
      // lower boundary of Carpet's integer indexing
      global_lower[d] = cctk_origin_space[d];
      // grid spacing of Carpet's integer indexing
      coord_delta[d] = (cctk_delta_space[d] /
                        vhh.at(m)->baseextents.at(0).at(0).stride()[d]);
    }
  } else {
    for (int d = 0; d < dim; ++d) {
      global_lower[d] = 0.0;
      coord_delta[d] = 1.0;
    }
  }

  coord_lower = global_lower + coord_delta * rvect(ext.lower());
  coord_upper = global_lower + coord_delta * rvect(ext.upper());
}

int GetGridOffset(const cGH *const cctkGH, const int m, const int dir,
                  const char *const iparam, const char *const iglobal,
                  const char *const cparam, const char *const cglobal,
                  const CCTK_REAL cfallback) {
  // First choice: explicit coordinate
  const int ncparam = CCTK_ParameterQueryTimesSet(cparam, CCTK_THORNSTRING);
  assert(ncparam >= 0);
  if (ncparam > 0) {
    int ptype;
    const CCTK_REAL *const pcoord = ((const CCTK_REAL *)CCTK_ParameterGet(
        cparam, CCTK_THORNSTRING, &ptype));
    assert(pcoord);
    const CCTK_REAL coord = *pcoord;
    assert(ptype == PARAMETER_REAL);
    return CoordToOffset(cctkGH, m, dir, coord, 0);
  }

  // Second choice: explicit index
  const int niparam = CCTK_ParameterQueryTimesSet(iparam, CCTK_THORNSTRING);
  assert(niparam >= 0);
  if (niparam > 0) {
    int ptype;
    const int *const pindex =
        (const int *)CCTK_ParameterGet(iparam, CCTK_THORNSTRING, &ptype);
    assert(pindex);
    const int index = *pindex;
    assert(ptype == PARAMETER_INT);
    return index;
  }

  // Third choice: explicit global coordinate
  const char *iothorn = CCTK_ImplementationThorn("IO");
  assert(iothorn);
  if (cglobal) {
    const int ncglobal = CCTK_ParameterQueryTimesSet(cglobal, iothorn);
    assert(ncglobal >= 0);
    if (ncglobal > 0) {
      int ptype;
      const CCTK_REAL *const pcoord =
          (const CCTK_REAL *)CCTK_ParameterGet(cglobal, iothorn, &ptype);
      assert(pcoord);
      const CCTK_REAL coord = *pcoord;
      assert(ptype == PARAMETER_REAL);
      return CoordToOffset(cctkGH, m, dir, coord, 0);
    }
  }

  // Fourth choice: explicit global index
  if (iglobal) {
    const int niglobal = CCTK_ParameterQueryTimesSet(iglobal, iothorn);
    assert(niglobal >= 0);
    if (niglobal > 0) {
      int ptype;
      const int *const pindex =
          (const int *)CCTK_ParameterGet(iglobal, iothorn, &ptype);
      assert(pindex);
      const int index = *pindex;
      assert(ptype == PARAMETER_INT);
      return index;
    }
  }

  // Fifth choice: default coordinate
  return CoordToOffset(cctkGH, m, dir, cfallback, 0);
}

int CoordToOffset(const cGH *cctkGH, const int m, const int dir,
                  const CCTK_REAL coord, const int ifallback) {
  assert(m >= 0 and m < Carpet::maps and dir >= 1 and dir <= dim);

  assert(mglevel != -1 and reflevel != -1 and Carpet::map == -1);

  rvect const cctk_origin_space = origin_space.at(m).at(mglevel);
  rvect const cctk_delta_space = delta_space.at(m) * rvect(mglevelfact);
  ivect const cctk_levfac = spacereffacts.at(reflevel);
  ibbox const &coarseext = vhh.at(m)->baseextents.at(mglevel).at(0);
  ibbox const &baseext = vhh.at(m)->baseextents.at(mglevel).at(reflevel);
  ivect const cctk_levoff = baseext.lower() - coarseext.lower();
  ivect const cctk_levoffdenom = baseext.stride();

  const CCTK_REAL delta = cctk_delta_space[dir - 1] / cctk_levfac[dir - 1];
  const CCTK_REAL lower = cctk_origin_space[dir - 1] +
                          cctk_delta_space[dir - 1] / cctk_levfac[dir - 1] *
                              cctk_levoff[dir - 1] / cctk_levoffdenom[dir - 1];

  const CCTK_REAL rindex = (coord - lower) / delta;
  int cindex = (int)floor(rindex + 0.75);

  return cindex;
}

CCTK_REAL nicelooking(const CCTK_REAL val, const CCTK_REAL base) {
  return floor(val / base + 0.5) * base;
}

// Output
template <int outdim>
void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                const bbox<int, dim> &gfext, const int vi, const int time,
                const vect<int, dim> &org, const vect<int, outdim> &dirs,
                const int rl, const int ml, const int m, const int c,
                const int tl, const CCTK_REAL coord_time,
                const vect<CCTK_REAL, dim> &coord_lower,
                const vect<CCTK_REAL, dim> &coord_upper,
                vector<gdata *> const &gfcoords) {
  DECLARE_CCTK_PARAMETERS;

  assert(outdim <= dim);

  const int vartype = CCTK_VarTypeI(vi);
  const int grouptype = CCTK_GroupTypeFromVarI(vi);
  const int groupdim = CCTK_GroupDimFromVarI(vi);

  if (CCTK_EQUALS(out_fileinfo, "axis labels") or
      CCTK_EQUALS(out_fileinfo, "all")) {

    assert(os.good());

    if (not compact_format or grouptype == CCTK_GF) {
      // Don't output a comment with iteration number and time,
      // because these are always output with the real data anyway
      os << "# iteration " << time << "   time " << coord_time << eol;
      os << "# time level " << tl << eol;
      os << "# refinement level " << rl << "   multigrid level " << ml
         << "   map " << m << "   component " << c << eol;
    }
    static vector<bool> did_output_format;
    if (did_output_format.empty()) {
      did_output_format.resize(CCTK_NumVars());
    }
    if (not compact_format or not did_output_format.AT(vi)) {
      did_output_format.AT(vi) = true;
      os << "# column format: 1:it";
      int col = 2;
      if (not compact_format or output_all_timelevels) {
        os << "\t" << col++ << ":tl";
      }
      if (not compact_format) {
        os << "\t" << col++ << ":rl";
        os << " " << col++ << ":c";
        os << " " << col++ << ":ml";
      }
      assert(dim >= 0 and dim <= 3);
      const char *const coords = "xyz";
      if (not compact_format) {
        for (int d = 0; d < dim; ++d) {
          os << (d == 0 ? "\t" : " ") << col++ << ":i" << coords[d];
        }
      } else {
        for (int d = 0; d < min(dim, groupdim); ++d) {
          os << (d == 0 ? "\t" : " ") << col++ << ":i" << coords[d];
        }
      }
      os << "\t" << col++ << ":time";
      if (not compact_format or grouptype == CCTK_GF) {
        for (int d = 0; d < dim; ++d) {
          os << (d == 0 ? "\t" : " ") << col++ << ":" << coords[d];
        }
      }
      os << "\t" << col << ":data" << eol;
      if (one_file_per_group) {
        os << "# data columns:";
        int const gindex = CCTK_GroupIndexFromVarI(vi);
        int const firstvar = CCTK_FirstVarIndexI(gindex);
        int const numvars = CCTK_NumVarsInGroupI(gindex);
        for (int n = firstvar; n < firstvar + numvars; ++n) {
          os << " " << col << ":" << CCTK_VarName(n);
          col += CarpetSimpleMPIDatatypeLength(vartype);
        }
        os << eol;
      }
    }

  } // if out_fileinfo

  // boolean that says if we are doing 1D-diagonal output
  // This is not beautiful, but works for the moment
  bool const diagonal_output = outdim == 1 and dirs[0] == 3;

  if (not diagonal_output) { // not outputting the diagonal

    const vect<int, outdim> lo = gfext.lower()[dirs];
    const vect<int, outdim> up = gfext.upper()[dirs];
    const vect<int, outdim> str = gfext.stride()[dirs];
    const bbox<int, outdim> ext(lo, up, str);

    // check whether the output origin is contained in the extent of
    // the data that should be output
    ivect org1(org);
    for (int d = 0; d < outdim; ++d)
      org1[dirs[d]] = ext.lower()[d];
    if (gfext.contains(org1)) {

      typename bbox<int, outdim>::iterator it = ext.begin();
      do {

        ivect index(org);
        for (int d = 0; d < outdim; ++d)
          index[dirs[d]] = (*it)[d];
        os << time;
        if (not compact_format or output_all_timelevels) {
          os << "\t" << tl;
        }
        if (not compact_format) {
          // Don't output the grid structure in compact format (it
          // is still output in the comments above every component)
          os << "\t" << rl << " " << c << " " << ml;
        }
        if (not compact_format) {
          for (int d = 0; d < dim; ++d) {
            os << (d == 0 ? "\t" : " ") << index[d];
          }
        } else {
          // In the compact format, output one column for each of
          // the group's dimension, don't always output three
          // columns
          for (int d = 0; d < min(dim, groupdim); ++d) {
            os << (d == 0 ? "\t" : " ") << index[d];
          }
        }
        os << "\t" << coord_time;
        if (not compact_format or grouptype == CCTK_GF) {
          for (int d = 0; d < dim; ++d) {
            os << (d == 0 ? "\t" : " ");
            assert(gfext.upper()[d] - gfext.lower()[d] >= 0);
            if (gfcoords.empty()) {
              // Calculate coordinates
              if (gfext.upper()[d] - gfext.lower()[d] == 0) {
                os << coord_lower[d];
              } else {
                CCTK_REAL const dx = ((coord_upper[d] - coord_lower[d]) /
                                      (gfext.upper()[d] - gfext.lower()[d]));
                os << (nicelooking(coord_lower[d] +
                                       (index[d] - gfext.lower()[d]) * dx,
                                   dx * 1.0e-8));
              }
            } else {
              // Use coordinate grid functions
              const gdata *gfcoord = gfcoords.at(d);
              os << (*(const data<CCTK_REAL> *)gfcoord)[index];
            }
          }
        }
        for (size_t n = 0; n < gfdatas.size(); ++n) {
          const gdata *gfdata = gfdatas.at(n);
          os << (n == 0 ? "\t" : " ");
          switch (specific_cactus_type(vartype)) {
#define CARPET_NO_COMPLEX
#define TYPECASE(N, T)                                                         \
  case N:                                                                      \
    os << (*(const data<T> *)gfdata)[index];                                   \
    break;
#include "typecase.hh"
#undef TYPECASE
#undef CARPET_NO_COMPLEX
#define CARPET_COMPLEX
#define TYPECASE(N, T)                                                         \
  case N:                                                                      \
    os << real((*(const data<T> *)gfdata)[index]) << " "                       \
       << imag((*(const data<T> *)gfdata)[index]);                             \
    break;
#include "typecase.hh"
#undef TYPECASE
#undef CARPET_COMPLEX
          default:
            UnsupportedVarType(vi);
          }
        } // for n
        os << eol;

        ++it;

        for (int d = 0; d < outdim; ++d) {
          if ((*it)[d] != (*ext.end())[d])
            break;
          if (not compact_format or ext.shape()[d] > ext.stride()[d]) {
            // In the compact format, don't separate outputs that
            // consist of a single lines only
            os << eol;
          }
        }

      } while (it != ext.end());

    } else {

      if (not compact_format) {
        os << "#" << eol;
      }

    } // if not ext contains org

    assert(os.good());

  } else { // taking care of the diagonal

    const ivect lo = gfext.lower();
    const ivect up = gfext.upper();
    const ivect str = gfext.stride();
    const ibbox ext(lo, up, str);

    gh const &hh = *vhh.at(m);
    ibbox const &base = hh.baseextents.at(mglevel).at(reflevel);

    assert(base.stride()[0] == base.stride()[1] and
           base.stride()[0] == base.stride()[2]);

    // output the data on the diagonal
    for (int i = maxval(base.lower()); i <= minval(base.upper());
         i += base.stride()[0]) {

      ivect const pos = ivect(i, i, i);

      // check if the point in question is in our gf's extent
      if (gfext.contains(pos)) {
        os << time;
        if (not compact_format) {
          // Don't output the grid structure in compact format (it
          // is still output in the comments above every component)
          os << "\t" << tl << " " << rl << " " << c << " " << ml;
        }
        for (int d = 0; d < dim; ++d) {
          os << (d == 0 ? "\t" : " ") << pos[d];
        }
        os << "\t" << coord_time;
        for (int d = 0; d < dim; ++d) {
          os << (d == 0 ? "\t" : " ");
          assert(gfext.upper()[d] - gfext.lower()[d] >= 0);
          if (gfext.upper()[d] - gfext.lower()[d] == 0) {
            os << coord_lower[d];
          } else {
            CCTK_REAL const dx = ((coord_upper[d] - coord_lower[d]) /
                                  (gfext.upper()[d] - gfext.lower()[d]));
            os << (nicelooking(coord_lower[d] +
                                   (pos[d] - gfext.lower()[d]) * dx,
                               dx * 1.0e-8));
          }
        }
        for (size_t n = 0; n < gfdatas.size(); ++n) {
          const gdata *gfdata = gfdatas.at(n);
          os << (n == 0 ? "\t" : " ");
          switch (specific_cactus_type(vartype)) {
#define TYPECASE(N, T)                                                         \
  case N:                                                                      \
    os << (*(const data<T> *)gfdata)[pos];                                     \
    break;
#include "typecase.hh"
#undef TYPECASE
          default:
            UnsupportedVarType(vi);
          }
        } // for n
        os << eol;

      } else {

        if (not compact_format) {
          os << "#" << eol;
        }

      } // if not ext contains org

    } // end for loop

    if (not compact_format or maxval(base.lower()) > minval(base.upper())) {
      // In the compact format, don't separate outputs that consist
      // of a single lines only
      os << eol;
    }

    assert(os.good());

  } // if diagonal_output
}

// Explicit instantiation for all output dimensions
template struct IOASCII<0>;
template struct IOASCII<1>;
template struct IOASCII<2>;
template struct IOASCII<3>;

template void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                         const bbox<int, dim> &gfext, const int vi,
                         const int time, const vect<int, dim> &org,
                         const vect<int, 0> &dirs, const int rl, const int ml,
                         const int m, const int c, const int tl,
                         const CCTK_REAL coord_time,
                         const vect<CCTK_REAL, dim> &coord_lower,
                         const vect<CCTK_REAL, dim> &coord_upper,
                         vector<gdata *> const &gfcoords);

template void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                         const bbox<int, dim> &gfext, const int vi,
                         const int time, const vect<int, dim> &org,
                         const vect<int, 1> &dirs, const int rl, const int ml,
                         const int m, const int c, const int tl,
                         const CCTK_REAL coord_time,
                         const vect<CCTK_REAL, dim> &coord_lower,
                         const vect<CCTK_REAL, dim> &coord_upper,
                         vector<gdata *> const &gfcoords);

template void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                         const bbox<int, dim> &gfext, const int vi,
                         const int time, const vect<int, dim> &org,
                         const vect<int, 2> &dirs, const int rl, const int ml,
                         const int m, const int c, const int tl,
                         const CCTK_REAL coord_time,
                         const vect<CCTK_REAL, dim> &coord_lower,
                         const vect<CCTK_REAL, dim> &coord_upper,
                         vector<gdata *> const &gfcoords);

template void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                         const bbox<int, dim> &gfext, const int vi,
                         const int time, const vect<int, dim> &org,
                         const vect<int, 3> &dirs, const int rl, const int ml,
                         const int m, const int c, const int tl,
                         const CCTK_REAL coord_time,
                         const vect<CCTK_REAL, dim> &coord_lower,
                         const vect<CCTK_REAL, dim> &coord_upper,
                         vector<gdata *> const &gfcoords);

} // namespace CarpetIOASCII

```

util/mergeCarpetIOASCII.pl:
```
#! /usr/bin/perl -w
#/*@@
#  @file      mergeCarpetIOASCII.pl
#  @date      Tue 15 August 2006
#  @author    Thomas Radke
#  @desc
#             Perl script to merge CarpetIOASCII output files,
#             eliminating duplicate datasets.
#
#             Source code comments also by Thomas Radke :-)
#  @enddesc
#@@*/


my $help = $#ARGV < 0;
for (my $arg = 0; $arg <= $#ARGV; $arg++) {
  $help |= ($ARGV[$arg] eq '-h'    or
            $ARGV[$arg] eq '-help' or
            $ARGV[$arg] eq '--help');
}
if ($help) {
  print << "EOF";

  Usage: $0 [-h | -help | --help] <list of files>

  This script can be used to merge  CarpetIOASCII output  written before
  and after recovery. It reads one or more files in CarpetIOASCII format
  and  writes their contents  to STDOUT,  eliminating duplicate datasets
  (all but the last occurance are discarded).

    Example: $0 alp.x.asc > alp.x.asc.merged

EOF
  exit;
}

# Rauten-Feld zum Merken der Anzahl und Haeufigkeit vorhandener Datensaetze
my %datasets = ();

# Liste aller Eingabe-Dateien
my @filelist = @ARGV;

# lies zeilenweise alle Eingabe-Dateien
while (<>) {

  # falls diese Zeile einen neuen Datensatz einleitet:
  if (/^# iteration (\d+)$/) {

    # ermittle die Iterationsnummer aus der aktuellen Zeile ...
    my $iteration = $1;

    # ... und die anderen Kennwerte dieses Datensatzes aus der folgenden Zeile
    $_ = <>;
    die "Format error in file $ARGV line $.: expected '# refinement level ...'\n"
      unless (/^# refinement level (\d+)   multigrid level (\d+)   map (\d+)   component (\d+)   time level (\d+)$/);

    # vermerke den Datensatz mit seinen Parametern
    ++$datasets{"$iteration $1 $2 $3 $4 $5"};
  }
} continue {
  # setze die Zeilennummer fuer jede Eingabe-Datei wieder zurueck
  close ARGV if eof;
}

# stelle die Liste aller Eingabe-Dateien wieder her
@ARGV = @filelist;

# Flaggen-Variable, die anzeigt, ob die aktuelle Zeile ignoriert werden soll
my $discard = 0;

# lies zeilenweise alle Eingabe-Dateien
while (<>) {

  # falls diese Zeile einen neuen Datensatz einleitet:
  if (/^# iteration (\d+)$/) {

    # gib die aktuelle (Kommentar-)Zeile aus
    print;

    # ermittle die Iterationsnummer aus der aktuellen Zeile ...
    my $iteration = $1;

    # ... und die anderen Kennwerte dieses Datensatzes aus der folgenden Zeile
    $_ = <>;
    $_ =~ /^# refinement level (\d+)   multigrid level (\d+)   map (\d+)   component (\d+)   time level (\d+)$/;

    # erzeuge einen eindeutigen Schluessel fuer den aktuellen Datensatz
    my $key = "$iteration $1 $2 $3 $4 $5";

    # ueberspringe alle Datensaetze mit denselben Kennwerten bis auf den letzten
    $discard = --$datasets{"$iteration $1 $2 $3 $4 $5"};
  }

  print unless $discard;
}

```

util/carpet2sdf.c:
```

/*******************************************************************
 * Program: carpet2sdf
 * Description: Converts from Carpet ASCII file format to SDF format
 * Author:  Scott H. Hawley
 * Date:    June 17, 2002
 *
 * Similar to carpet2sdf, except that instead of sending output to
 * sdtout, it sends it to <infile>.sdf
 *******************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bbhutil.h>

/*******************************************************************
 * Function: read_next_set
 * Supposed to read one time step of data (for one level of refinement)
 *******************************************************************/
int read_next_set(FILE *infile, int rlev, int *numelems, double *time,
                  double **coord, double **data, int clip_data,
                  double clip_val) {
  char in_line[200];
  int it, tl, rl, c, ml, ix, iy, iz;
  double xval, yval, zval;
  double coordval, dataval;
  int hit_first_non_blank = 0;
  int stop_reading = 0;
  int retval = 0;
  int rc = 0;

  *numelems = 0;
  sprintf(in_line, " ");

  /* reads up to first blank line after non-blank lines, or up to
   * eof */
  while ((fgets(in_line, 200, infile) != NULL) && (!stop_reading)) {

    if (in_line[0] == '#') {
      hit_first_non_blank = 1;

    } else if ((strncmp("\n", in_line, 2) == 0) || (in_line[0] == ' ')) {
      if (hit_first_non_blank) {
        stop_reading = 1;
      }

    } else { /* Assume that we're dealing with a line of numbers */
      hit_first_non_blank = 1;
      retval = sscanf(in_line, "%d %d %d %d %d %d %d %d %lg %lg %lg %lg %lg",
                      &it, &tl, &rl, &c, &ml, &ix, &iy, &iz, time, &xval, &yval,
                      &zval, &dataval);
      coordval = xval;

      /* Only add input to arrays if it's for the right ref. level */
      if ((retval == 13) && (rl == rlev)) {
        (*numelems)++;

        if (coord == NULL) {
          *coord = (double *)malloc(sizeof(double) * (*numelems));
          *data = (double *)malloc(sizeof(double) * (*numelems));
        } else {
          *coord = (double *)realloc(*coord, sizeof(double) * (*numelems));
          *data = (double *)realloc(*data, sizeof(double) * (*numelems));
        }
        if (coord == NULL) {
          fprintf(stderr, "Error: malloc/realloc returned NULL\n");
          exit(1);
        }

        (*coord)[(*numelems) - 1] = coordval;

        /* If desired, "clip" data above a certain value */
        if (clip_data && (dataval > clip_val)) {
          (*data)[(*numelems) - 1] = clip_val;
        } else {
          (*data)[(*numelems) - 1] = dataval;
        }
      }
    }
  }
  rc = feof(infile);

  return rc;
}

/********************************************************************
 * Main part of program
 ********************************************************************/
int main(int argc, char **argv) {
  char *infilename;
  FILE *infile;

  char func_name[200];
  double time;
  int shape[1];
  double bounds[2];
  int rank = 1;
  int numelems_in_set = 0;
  int rlev = 0;
  double *coord, *data;
  int clip_data = 0;
  double clip_val;

  /*
   * Parse command-line arguments
   */
  if (argc <= 1) {
    fprintf(stderr, "usage: carpet2sdf <infile> [ref_lev] [clip_data_at]\n");
    exit(1);
  }
  if (argc >= 3) {
    sscanf(argv[2], "%d", &rlev);
  }
  if (argc >= 4) {
    sscanf(argv[3], "%lf", &clip_val);
    clip_data = 1;
  }

  /*
   * Open the input file
   */
  infilename = argv[1];
  infile = fopen(infilename, "r");
  if (infile == NULL) {
    fprintf(stderr, "Error opening file '%s'.\n", infilename);
    exit(1);
  }

  time = 0;
  coord = NULL;
  data = NULL;
  sprintf(func_name, "%s_%d", infilename, rlev);

  /*
   * Main loop for reading from input file and writing to output file
   */
  while (read_next_set(infile, rlev, &numelems_in_set, &time, &coord, &data,
                       clip_data, clip_val) == 0) {
    if (numelems_in_set > 0) {

      shape[0] = numelems_in_set;
      bounds[0] = coord[0];
      bounds[1] = coord[numelems_in_set - 1];

      gft_out_bbox(func_name, time, shape, rank, bounds, data);

      free(coord);
      free(data);
      coord = NULL;
      data = NULL;
    }
  }

  return 0;
}

```

util/Carpet2ygraphCat.pl:
```
#! /usr/bin/perl -sw
#
# Given an output file in CarpetIOScalar format or
# CarpetIOASCII scalar or 1d format, strip to ygraph format.

# Output is to a file named after the input file, with its extension ".asc"
# substituted by ".xg".
#
# Example:
#
#   Carpet2ygraphCat.pl alp.x.asc
#
# produces alp.x.xg
#
#   Carpet2ygraph.pl alp.minimum.asc
#
# produces alp.minumum.xg
#
# Some headers of the Carpet files are just copied with the addition of
# the correct time for ygraph, and the different comment marker.
#
# This script is an altered version of Ian Hawke's script.
#


use FileHandle;

if(@ARGV != 1 and @ARGV != 2)
{
  print "Usage: $0 <Inputfile> [<Data Column (0..n)>]\n";
  exit;
}

my $direction;
my $infile = shift;
my $varindex = 0;
$varindex = shift if @ARGV == 1;

open(CARPETFILE, "< $infile") || die "Unable to find input file '$infile'\n.";

if ($infile =~ /\.(x|y|z|d)\.asc$/) {
  $direction = ord($1) - ord('x') + 9;
  print "extracting CarpetIOASCII 1D data in direction $1...\n";
} elsif ($infile =~ /\.\.asc$/) {
  $direction = 8;
  print "extracting CarpetIOASCII 0D data...\n";
} elsif ($infile =~ /\.asc$/) {
  $direction = 0;
  print "extracting CarpetIOScalar data...\n";
} else {
  die "Do not recognize input file format for '$infile'.\n";
}


# deal with scalar output
if ($direction == 0) {
  local @dataColumns = ();
  while (<CARPETFILE>) {
    if (/^# data columns: (.+)/) {
      @dataColumns = split(/[ :]/, $1);
      last;
    }
  }
  # seek back to the beginning of the file
  seek(CARPETFILE, 0, 0);

  my $outfile = $infile;
  $outfile =~ s/asc$/xg/;
  if (exists $dataColumns[$varindex*2 + 1]) {
    local @tokens = split(/::/, $outfile);
    if (@tokens) {
      $outfile = $tokens[0] . '::';
      @tokens = split(/\./, $tokens[1]);
    } else {
      @tokens = split('.', $outfile);
      $outfile = '';
    }
    $tokens[0] = $dataColumns[$varindex*2 + 1];
    $outfile .= join('.', @tokens);
  }
  print "  output to file '$outfile'\n\n";

  local $fh = new FileHandle("> $outfile") || die "Unable to open output file '$outfile'.\n";
  while (<CARPETFILE>) {
    # The line is not a header comment
    if(/^[0-9]/) {
      my @data = split(/\s+/);
      if (not defined $data[$varindex + 2]) {
        print STDERR "\nInput file '$infile' has no values in data column " .
                     "$varindex.\n" . "Please specify a valid column index " .
                     "(starting from 0) !\n\n";
        exit -1;
      }
      print $fh $data[1]." ".$data[$varindex + 2]."\n";
    }
  }
  close ($fh);
  exit;
}


my %data;
my $time = -1;
my $new = 0;
my $lastit = -1;

my @datatoprint;
my $nsets = 1;
my $maxlength = 0;
my @lengths;
my @dataColumns = ();

$lengths[0]=0;
while (<CARPETFILE>)
{
  chomp;
  next if (/^$/);

  @dataColumns = split(/[ :]/, $1) if (/^# data columns: (.+)/);

  #Do nothing for headers!
  next if (/^#/);

  my @dataline = split(/[ \t]+/);
  my $currentit = $dataline[0];
  if ($currentit != $lastit) {
    if ($new) {
      # do not print "Time..." for zero-D data
      push(@datatoprint,"\n\n\#Time = $time\n") if ($direction !~ 8);

      my @sortedcoords = sort {$a <=> $b} (keys %data);
      foreach my $localcoord (@sortedcoords) {
        push(@datatoprint, $localcoord." ".$data{$localcoord}."\n");
      }
      $maxlength = $maxlength > (scalar @sortedcoords) ? $maxlength : (scalar @sortedcoords);
      $lengths[$nsets-1]=(scalar @sortedcoords);
      $nsets++;
      $lengths[$nsets-1]=0;
      %data=();
    }
    $new++;
    $time = $dataline[8];
    $lastit = $currentit;
  }
  my $coord = $dataline[$direction];
  if (not defined $dataline[12 + $varindex]) {
    print STDERR "\nInput file '$infile' has no values in data column " .
                 "$varindex.\n" . "Please specify a valid column index " .
                 "(starting from 0) !\n\n";
    exit -1;
  }
  my $val = $dataline[12 + $varindex];
  $data{$coord} = $val;
}

# do not print "Time..." for zero-D data
push(@datatoprint,"\n\n\#Time = $time\n") if ($direction !~ 8);

my @sortedcoords = sort {$a <=> $b} (keys %data);
foreach my $localcoord (@sortedcoords) {
  push(@datatoprint, $localcoord." ".$data{$localcoord}."\n");
}
$maxlength = $maxlength > (scalar @sortedcoords) ? $maxlength : (scalar @sortedcoords);
$lengths[$nsets-1]=(scalar @sortedcoords);
$nsets++;
$lengths[$nsets-1]=0;

my $outfile = $infile;
$outfile =~ s/asc$/xg/;
if (exists $dataColumns[$varindex*2 + 1]) {
  my @tokens = split(/::/, $outfile);
  if (@tokens) {
    $outfile = $tokens[0] . '::';
    @tokens = split(/\./, $tokens[1]);
  } else {
    @tokens = split('.', $outfile);
    $outfile = '';
  }
  $tokens[0] = $dataColumns[$varindex*2 + 1];
  $outfile .= join('.', @tokens);
}
print "  output to file '$outfile'\n\n";

my $fh = new FileHandle("> $outfile") or die "Unable to open output file '$outfile'.\n";

my $oldline="";
$nouts=0;
my $set=0;
foreach $line (@datatoprint) {
  if ($line =~ "Time") {
    if ($oldline) {
      for (my $i=$lengths[$set-1]; $i<$maxlength;$i++) {
        $nouts++;
        print $fh $oldline;
      }
    }
    $set++;
    print $fh $line;
  }
  else {
    $nouts++;
    print $fh $line;
    $oldline=$line
  }
}

# TR: I don't see why this is needed, it seems to print the last data item twice
# in CarpetIOBasic 0D output
#for (my $i=$lengths[$set-1]; $i<$maxlength;$i++) {
#  $nouts++;
#  print $fh $oldline;
#}

```

util/Carpet2ygraph.pl:
```
#! /usr/bin/perl -sw
#
# Blame Ian Hawke for not checking that Scott had already written a C
# program to do this add so writing a perl version instead
#
# Given an output file in CarpetIOASCII 1d format, strip to ygraph format.
# The arguments should be direction (x=0,y=1,z=2) and filename.
# Output is to a file. Only the base name should be given.
# The base will be appended with _<level>.xg
#
# Example:
#
# Carpet2ygraph.pl 0 alp.xl alp_x
#
# produces alp_x_<d>.xg where <d> is the refinement level.
#
# The headers of the Carpet files are just copied with the addition of
# the correct time for ygraph, and the different comment marker.
#
# This script is a much altered version of Tom Goodale's convergence
# testing scripts.
#

use FileHandle;

if(@ARGV != 3 or $ARGV[0] !~ /^0|1|2$/)
{
  print "Usage: $0 direction <Inputfile> <Outputfile>\n";
  print "       where direction is either 0, 1, 2\n";
  exit;
}

open(CARPETFILE,   "<$ARGV[1]") || die "Unable to find file \"$ARGV[1]\"."; 

my $direction = $ARGV[0]+9; 
my $flag = 0;
my $newflag = 0;
my $refinementlevel = 0;
my %componentflag = ();
$componentflag{$refinementlevel} = 0;
my @outputdata = ("\n");

#
# Open the output file for the base grid. 
#
my $file = $ARGV[2]."_$refinementlevel.xg";
my %outputfilelist = ();
$outputfilelist{$refinementlevel} =
  new FileHandle(">$file") || die "Unable to open file \"$file\"."; 

#
# Find the correct column for the spatial coordinate; requires a magic number
#
while (<CARPETFILE>)
{
    # skip empty lines
    next if (/^(\s)*$/);

    $line = $_;

    if(/^\#/) # The line is a header comment
    {
	if ($flag==1) # It's a new level and there is data to output
        {
	    my $fh = $outputfilelist{$refinementlevel};
	    print $fh @outputdata;
	    @outputdata=("\n");
	    $flag = 0;
	}
	if ($line =~ /refinement level ([0-9]{1,2})/) # Line gives ref. level
	{
	    $refinementlevel = $1;
	    $line =~ /component ([0-9+])/;
	    $componentflag{$refinementlevel} = $1; # Which component?

	    # If no file exists for this refinement level, 
	    # open and add filehandle to list
	    if (not defined $outputfilelist{$refinementlevel})
	    { 
		$file = $ARGV[2] . "_$refinementlevel.xg";
		$outputfilelist{$refinementlevel} = 
		  new FileHandle(">$file") || die "Unable to open file \"$file\"."; 
	    }
	}
	# Only output the headers if this is the zero component
	# FIXME: what happens if component 0 isn't output first?
	if (0 == $componentflag{$refinementlevel})
	{
	    push(@outputdata, ("\"",$line)); # Add ygraph comment marker
	    $newflag = 0;
	}
	else
	{
	    $flag = 1;
	    @outputdata=("");
	}
    }
    else # The line contains real data
    {
	@data = split(/[ \t]+/,$line);
	if (($newflag==0)) # This is the first line of data
	{
	    $newflag = 1;
	    my $timeset = $data[8]; # Magic number gives the Cactus time
	    @outputdata = ("\n\n\#Time = $timeset \n",@outputdata);
	}
        chomp ($data[12]);
        push(@outputdata, "$data[$direction] $data[12]\n");
    }
}

#
# At end of file, so output final data set.
#
my $fh = $outputfilelist{$refinementlevel};
print $fh @outputdata;

foreach $refinementlevel (keys %outputfilelist)
{
    close($outputfilelist{$refinementlevel});
}

```

util/carpet2xgraph.c:
```

/*******************************************************************
 * Program: carpet2xgraph
 * Description: Converts from Carpet ASCII file format to Xgraph format
 * Author:  Scott H. Hawley
 * Date:    June 17, 2002
 *
 * This will select the data for ONE REFINEMENT LEVEL (default 0)
 * and send the result to stdout.   The "xgraph format" data is
 * not, however, fully annotated and someone may wish to improve
 * this.
 *
 * The [clip_data_at] command-line argument was added for use with
 * 1/r data, to replace the infinities at the origin with whatever
 * value the user specifies.
 *******************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*******************************************************************
 * Function: read_next_set
 * Supposed to read one time step of data (for one level of refinement)
 *******************************************************************/
int read_next_set(FILE *infile, int rlev, int *numelems, double *time,
                  double **coord, double **data, int clip_data,
                  double clip_val);
int read_next_set(FILE *infile, int rlev, int *numelems, double *time,
                  double **coord, double **data, int clip_data,
                  double clip_val) {
  char in_line[200];
  int it, tl, rl, c, ml, ix, iy, iz;
  double xval, yval, zval;
  double coordval, dataval;
  int hit_first_non_blank = 0;
  int stop_reading = 0;
  int retval = 0;
  int rc = 0;

  *numelems = 0;
  sprintf(in_line, " ");

  /* reads up to first blank line after non-blank lines, or up to
   * eof */
  while ((fgets(in_line, 200, infile) != NULL) && (!stop_reading)) {

    if (in_line[0] == '#') {
      hit_first_non_blank = 1;

    } else if ((strncmp("\n", in_line, 2) == 0) || (in_line[0] == ' ')) {
      if (hit_first_non_blank) {
        stop_reading = 1;
      }

    } else { /* Assume that we're dealing with a line of numbers */
      hit_first_non_blank = 1;
      retval = sscanf(in_line, "%d %d %d %d %d %d %d %d %lg %lg %lg %lg %lg",
                      &it, &tl, &rl, &c, &ml, &ix, &iy, &iz, time, &xval, &yval,
                      &zval, &dataval);
      coordval = xval;

      /* Only add input to arrays if it's for the right ref. level */
      if ((retval == 13) && (rl == rlev)) {
        (*numelems)++;

        if (coord == NULL) {
          *coord = (double *)malloc(sizeof(double) * (*numelems));
          *data = (double *)malloc(sizeof(double) * (*numelems));
        } else {
          *coord = (double *)realloc(*coord, sizeof(double) * (*numelems));
          *data = (double *)realloc(*data, sizeof(double) * (*numelems));
        }
        if (coord == NULL) {
          fprintf(stderr, "Error: malloc/realloc returned NULL\n");
          exit(1);
        }

        (*coord)[(*numelems) - 1] = coordval;

        /* If desired, "clip" data above a certain value */
        if (clip_data && (dataval > clip_val)) {
          (*data)[(*numelems) - 1] = clip_val;
        } else {
          (*data)[(*numelems) - 1] = dataval;
        }
      }
    }
  }
  rc = feof(infile);

  return rc;
}

/********************************************************************
 * Main part of program
 ********************************************************************/
int main(int argc, char **argv) {
  char *infilename;
  FILE *infile;

  char func_name[200];
  double time;
  int numelems_in_set = 0;
  int rlev = 0;
  double *coord, *data;
  int clip_data = 0;
  double clip_val;
  int i;

  /*
   * Parse command-line arguments
   */
  if (argc <= 1) {
    fprintf(stderr, " input from stdin...  invoke carpet2xgraph -h for help\n");
  } else if (strcmp(argv[1], "-h") == 0) {
    fprintf(stderr, "usage: cat file | carpet2xgraph [name_tag] [ref_lev] "
                    "[clip_data_at]\n");
    exit(1);
  }

  if (argc >= 2) {
    infilename = argv[1];
  } else {
    infilename = "stdin";
  }
  if (argc >= 3) {
    sscanf(argv[2], "%d", &rlev);
  }
  if (argc >= 4) {
    sscanf(argv[3], "%lf", &clip_val);
    clip_data = 1;
  }

  /*
   * Open the input file
   */
  infile = stdin;

  /*
  infile = fopen(infilename,"r");
  if (infile == NULL) {
     fprintf(stderr,"Error opening file '%s'.\n",infilename);
     exit(1);
  }
  */

  time = 0;
  coord = NULL;
  data = NULL;
  sprintf(func_name, "%s_%d", infilename, rlev);

  printf("\"x-label x\n");
  printf("\"y-label %s\n\n\n", infilename);
  printf("\"label = %s\n\n\n", infilename);

  /*
   * Main loop for reading from input file and writing to output file
   */
  while (read_next_set(infile, rlev, &numelems_in_set, &time, &coord, &data,
                       clip_data, clip_val) == 0) {
    if (numelems_in_set > 0) {

      /* xgraph format */
      printf("\"Time = %g\n", time);
      for (i = 0; i < numelems_in_set; i++) {
        printf("%g  %17.14g\n", coord[i], data[i]);
      }
      printf("\n\n");

      free(coord);
      free(data);
      coord = NULL;
      data = NULL;
    }
  }

  return 0;
}

```


combined_doc_context: ## README (README):
```
Cactus Code Thorn CarpetIOASCII
Author(s)    : Erik Schnetter <schnetter@cct.lsu.edu>
Maintainer(s): Erik Schnetter <schnetter@cct.lsu.edu>
Licence      : GPLv2+
--------------------------------------------------------------------------

1. Purpose

This thorn provides ASCII output for Carpet.

```

## Documentation (.tex files):
Files: documentation.tex

```tex
=== documentation.tex ===
\documentclass{article}

% Use the Cactus ThornGuide style file
% (Automatically used from Cactus distribution, if you have a 
%  thorn without the Cactus Flesh download this from the Cactus
%  homepage at www.cactuscode.org)
\usepackage{../../../../doc/latex/cactus}

\begin{document}

% The author of the documentation
\author{Erik Schnetter \textless schnetter@aei.mpg.de\textgreater\\
        Thomas Radke \textless tradke@aei.mpg.de\textgreater}

% The title of the document (not necessarily the name of the Thorn)
\title{CarpetIOASCII}

% the date your document was last changed, if your document is in CVS, 
% please use:
\date{November 20, 2005}

\maketitle

% Do not delete next line
% START CACTUS THORNGUIDE

\newcommand{\ThisThorn}{{\it CarpetIOASCII}}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{abstract}
  This thorn reproduces thorn IOASCII from arrangement CactusBase but
  is specifically for the driver thorn Carpet.
\end{abstract}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Introduction}

This thorn provides ASCII output of data in 1, 2 or 3 dimensions. It
reproduces most of the functionality of thorn IOASCII from the
standard CactusBase arrangement. Where possible the names of
parameters and their use is identical. For most purposes it should be
sufficient to take a parameter file written for the standard IOASCII
and just change the active thorn.

However, this thorn outputs considerably more information than the
standard IOASCII thorn. Information about, e.g., the refinement level
and the index position of the output are also given. All the output
can be visualized using gnuplot.

The \ThisThorn\ I/O methods can output any type of CCTK grid variables
(grid scalars, grid functions, and grid arrays of arbitrary dimension);
data is written into separate files named {\tt "<varname>.asc"}.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{\ThisThorn\ Parameters}

The most important parameters to control the \ThisThorn\ I/O methods are listed
below. Many parameters come as a set of four individuals, one for each
I/O method, controlling 0, 1, 2, or 3-dimensional ASCII output respectively.

\begin{itemize}
  \item {\tt IOASCII::out[0-3]D\_every} (steerable)\\
        How often to do periodic \ThisThorn\ output. If this parameter is set
        in the parameter file, it will override the setting of the shared
        {\tt IO::out\_every} parameter. The output frequency can also be set
        for individual variables using the {\tt out\_every} option in an
        option string appended to the {\tt IOASCII::out[0-3]D\_vars} parameter.
  
  \item {\tt IOASCII::out[0-3]D\_dt} (steerable)\\
        output in intervals of that much coordinate time (overwrites
        {\tt IO::out\_dt})
  
  \item {\tt IOASCII::out[0-3]D\_criterion} (steerable)\\
        criterion to select output intervals (overwrites
        {\tt IO::out\_criterion})
  
  \item {\tt IOASCII::out[0-3]D\_vars} (steerable)\\ 
        The list of variables to output using the \ThisThorn\ I/O method.
        The variables must be given by their fully qualified variable or group
        name. The special keyword {\it all} requests \ThisThorn\ output for
        all variables. Multiple names must be separated by whitespaces.

        Each group/variable name can have an option string attached in which you
        can specify a different output frequency for that individual variable,
        or a set of individual refinement levels to be output, eg.
\begin{verbatim}
  IOASCII::out1D_vars = "wavetoy::phi{ out_every = 4 refinement_levels = { 1 2 } }"
\end{verbatim}
  
  \item {\tt IOASCII::out[0-3]D\_dir}\\
        The directory in which to place the \ThisThorn\ output files.
        If the directory doesn't exist at startup it will be created.\\
        If this parameter is set to an empty string \ThisThorn\ output will go
        to the standard output directory as specified in {\tt IO::out\_dir}.
  
  \item {\tt IOASCII::out\_precision} (steerable)\\
        How many digits to output floating-point numbers with (overwrites
        {\tt IO::out\_precision}).

  \item {\tt IOASCII::one\_file\_per\_group}\\
        Write one output file per group instead of per variable.

\end{itemize}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Using the flesh I/O API to produce ASCII output}

Periodic output of grid variables is usually specified via I/O parameters
in the parameter file and then automatically triggered by the flesh scheduler
at each iteration step after analysis. If output should also be triggered
at a different time, one can do that from within an application thorn by
invoking one of the {\tt CCTK\_OutputVar*()} I/O routines provided
by the flesh I/O API (see chapter B8.2 ``IO'' in the Cactus Users Guide).
In this case, the application thorn routine which calls {\tt CCTK\_OutputVar*()}
must be scheduled in level mode.

If output for a variable is required also for intermediate timesteps
this can be achieved by calling {\tt CCTK\_OutputVarAs*()} with a different
{\tt alias} name; output for the same variable is then written into
different ASCII files based on the {\tt alias} argument.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Utilities}
\label{sec:utils}

For those that prefer other visualization packages than gnuplot there
are some utilities in the src/util directory. These are
\begin{itemize}
\item {\bf carpet2sdf} A program to convert to a format suitable for
  the {\it ser} program written by M. Choptuik,
\item {\bf carpet2xgraph} A program to convert to a format suitable
  for the {\it xgraph} or {\it ygraph} packages of P. Walker and D.
  Pollney,
\item {\bf Carpet2ygraph.pl} A perl script to convert to a format
  suitable for the {\it xgraph} or {\it ygraph} packages of P. Walker
  and D. Pollney.
\item {\bf Carpet2ygraph.pl} An improved version of the previous script.
\item {\bf mergeCarpetIOASCII.pl} A perl script to remove duplicate datasets from file(s).
\end{itemize}

The first two, written by Scott Hawley, are C codes that require the
Makefile (building using the -utils flag from the main Cactus
directory currently does not work). Each output one refinement level,
either to standard output or to a file.

The third script writes all refinement levels from a given file in a
given direction to a number of different files given a prefix
filename, where the number in the output filename is given by the
refinement level. Usage: {\tt Carpet2ygraph.pl direction Inputfile Outputfile},
where direction is 0, 1, 2, for x,y and z.

The fourth script is an improved version of the previous one. It reads a 1D .asc file and produces a
single file containing all the data from all levels, writing points that are in more levels only
once. The output filename is the original filename with the suffix .asc changed into .xg. The
direction (x,y or z) of the input file is automatically detected from the filename. It recognizes
and converts also scalar data, like norms and extrema. Usage: {\tt Carpet2ygraphCat.pl Inputfile}.

The fifth script can be used to merge CarpetIOASCII output written before and after recovery. It
reads one or more files in CarpetIOASCII format and writes their contents to STDOUT, eliminating
duplicate datasets (all but the last occurance are discarded), which may be created when a run died
abruptly without checkpointing at the last output itaration and is recovered from a previous
checkpoint.  
Usage: {\tt mergeCarpetIOASCII.pl list of files}. \\
Example 1: {\tt mergeCarpetIOASCII.pl alp.x.asc > alp.x.asc.merged}.\\ 
Example 2: {\tt mergeCarpetIOASCII.pl alp.x.asc.firstCHKPT alp.x.asc.secondCHKPT > alp.x.asc.merged}.\\
This script was written by Thomas Radke.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\begin{thebibliography}{9}
%
%\end{thebibliography}

% Do not delete next line
% END CACTUS THORNGUIDE

\end{document}

```



Reference answer:
src_code: #ifndef CARPETIOASCII_HH
#define CARPETIOASCII_HH

#include <vector>

#include <cctk.h>
#include <cctk_Arguments.h>

namespace CarpetIOASCII {

using namespace std;

// Scheduled functions
extern "C" {
int CarpetIOASCIIStartup(void);
void CarpetIOASCIIInit(CCTK_ARGUMENTS);
}

// routines which are independent of the output dimension
static ibbox GetOutputBBox(const cGH *cctkGH, int group, int rl, int m, int c,
                           const ibbox &ext);

static void GetCoordinates(const cGH *cctkGH, int m, const cGroup &groupdata,
                           const ibbox &ext, CCTK_REAL &coord_time,
                           rvect &coord_lower, rvect &coord_upper);

static int GetGridOffset(const cGH *cctkGH, int m, int dir, const char *iparam,
                         const char *iglobal, const char *cparam,
                         const char *cglobal, CCTK_REAL cfallback);
static int CoordToOffset(const cGH *cctkGH, int m, int dir, CCTK_REAL coord,
                         int ifallback);

// Everything is a class template, so that it can easily be
// instantiated for all output dimensions

template <int outdim> struct IOASCII {

  // name of the output directory
  static char *my_out_dir;

  // list of variables to output
  static char *my_out_vars;

  // I/O request description list (for all variables)
  static vector<ioRequest *> requests;

  // Scheduled functions
  static int Startup();

  // Registered functions
  static void *SetupGH(tFleshConfig *fc, int convLevel, cGH *cctkGH);

  static int OutputGH(const cGH *cctkGH);
  static int OutputVarAs(const cGH *cctkGH, const char *varname,
                         const char *alias);
  static int TimeToOutput(const cGH *cctkGH, int vindex);
  static int TriggerOutput(const cGH *cctkGH, int vindex);

  // Other functions
  static void CheckSteerableParameters(const cGH *cctkGH);

  static bool DidOutput(const cGH *cctkGH, int vindex, string basefilename,
                        bool &is_new_file, bool &truncate_file);

  static bool DirectionIsRequested(const vect<int, outdim> &dirs);

  static void OutputDirection(const cGH *cctkGH, int vindex, string alias,
                              string basefilename,
                              const vect<int, outdim> &dirs, bool is_new_file,
                              bool truncate_file);

  static void OpenFile(const cGH *cctkGH, int m, int vindex, string alias,
                       string basefilename, const vect<int, outdim> &dirs,
                       bool is_new_file, bool truncate_file, fstream &file);

  static void CloseFile(const cGH *cctkGH, fstream &file);

  static ivect GetOutputOffset(const cGH *cctkGH, int m,
                               const vect<int, outdim> &dirs);

}; // struct IOASCII

template <int outdim>
void WriteASCII(ostream &os, vector<gdata *> const &gfdatas,
                const bbox<int, dim> &gfext, const int vi, const int time,
                const vect<int, dim> &org, const vect<int, outdim> &dirs,
                const int rl, const int ml, const int m, const int c,
                const int tl, const CCTK_REAL coord_time,
                const vect<CCTK_REAL, dim> &coord_lower,
                const vect<CCTK_REAL, dim> &coord_upper,
                vector<gdata *> const &gfcoords);

} // namespace CarpetIOASCII

#endif // ! defined CARPETIOASCII_HH