CarpetIOF5: Write a meta-file containing an inventory

In addition to one data file per processor, also write out one
meta-data file containing an inventory and external links to the other
files.

Compiles.  Untested.

darcs-hash:20080115192202-dae7b-e709063fdbe7d545389cdcb40846a10451e9f4c1.gz

25 files changed, 597 insertions, 85 deletions

diff --git a/CarpetDev/CarpetIOF5/src/IOF5.cc b/CarpetDev/CarpetIOF5/src/IOF5.cc
index 83389906a..c21332adb 100644
--- a/CarpetDev/CarpetIOF5/src/IOF5.cc
+++ b/CarpetDev/CarpetIOF5/src/IOF5.cc
@@ -2,6 +2,7 @@
 #include <cassert>
 #include <cmath>
 #include <cstdlib>
+#include <cstring>
 #include <iomanip>
 #include <sstream>
 #include <string>
@@ -57,9 +58,6 @@ namespace CarpetIOF5 {
                   char const * options,
                   void * ptr);
   
-  static int
-  base_10_digits (int number);
-  
   
   
   static int
@@ -181,21 +179,6 @@ namespace CarpetIOF5 {
   
   
   int
-  base_10_digits (int number)
-  {
-    number = abs (number);
-    int digits = 1;
-    while (number >= 10)
-    {
-      number /= 10;
-      ++ digits;
-    }
-    return digits;
-  }
-  
-  
-  
-  int
   TimeToOutput (cGH const * const cctkGH,
                 int const variable)
   {
@@ -386,23 +369,18 @@ namespace CarpetIOF5 {
     
     extending_t extending (cctkGH);
     
-    ostringstream filenamebuf;
-    bool const use_IO_out_dir = strcmp (out_dir, "") == 0;
-    int const digits = base_10_digits (CCTK_nProcs (cctkGH) - 1);
-    filenamebuf << (use_IO_out_dir ? IO_out_dir : out_dir)
-                << "/"
-                << alias
-                << "."
-                << setw (digits) << setfill ('0') << CCTK_MyProc (cctkGH) 
-                << out_extension;
-    string const filename = filenamebuf.str();
-    
-    bool const did_truncate = extending.get_did_truncate (filename);
+    bool const use_IO_out_dir = std::strcmp (out_dir, "") == 0;
+    string const basename
+      = (use_IO_out_dir ? IO_out_dir : out_dir) + string ("/") + alias;
+    bool const want_metafile = CCTK_MyProc (cctkGH) == 0;
+    
+    bool const did_truncate = extending.get_did_truncate (basename);
     bool const do_truncate
       = not did_truncate and IO_TruncateOutputFiles (cctkGH);
-    extending.set_did_truncate (filename);
+    extending.set_did_truncate (basename);
     
-    F5::file_t file (cctkGH, filename, do_truncate);
+    F5::file_t file (cctkGH, basename, string (out_extension),
+                     want_metafile, do_truncate);
     
     writer_t writer (cctkGH, variable);
     writer.write (file);
diff --git a/CarpetDev/CarpetIOF5/src/README b/CarpetDev/CarpetIOF5/src/README
index 758b31bfa..8b51edf63 100644
--- a/CarpetDev/CarpetIOF5/src/README
+++ b/CarpetDev/CarpetIOF5/src/README
@@ -11,3 +11,5 @@ An F5 file contains the following hierarchy:
 
 2006-06-05: Werner says that tensor_component and data_region should
 be interchanged.
+
+2007-04-25: Werner confirms this.
diff --git a/CarpetDev/CarpetIOF5/src/coordinate_system.cc b/CarpetDev/CarpetIOF5/src/coordinate_system.cc
index 49c023921..bb5b6808f 100644
--- a/CarpetDev/CarpetIOF5/src/coordinate_system.cc
+++ b/CarpetDev/CarpetIOF5/src/coordinate_system.cc
@@ -117,6 +117,7 @@ namespace CarpetIOF5 {
       namebuf << "Cartesian 3D, x0=" << m_level_origin
               << ", dx=" << m_level_delta;
       string const namestr = namebuf.str();
+      m_name = namestr;
       char const * const name = namestr.c_str();
       
       m_hdf5_coordinate_system
@@ -131,6 +132,26 @@ namespace CarpetIOF5 {
     
     
     
+    void coordinate_system_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_topology().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool Cartesian_coordinate_system_t::
     invariant ()
       const
diff --git a/CarpetDev/CarpetIOF5/src/coordinate_system.hh b/CarpetDev/CarpetIOF5/src/coordinate_system.hh
index 06c93603e..3a36a458a 100644
--- a/CarpetDev/CarpetIOF5/src/coordinate_system.hh
+++ b/CarpetDev/CarpetIOF5/src/coordinate_system.hh
@@ -26,6 +26,8 @@ namespace CarpetIOF5 {
       
       topology_t & m_topology;
       
+      string m_name;
+      
       hid_t m_hdf5_coordinate_system;
       
       coordinate_system_t (topology_t & topology);
@@ -43,6 +45,11 @@ namespace CarpetIOF5 {
       get_hdf5_coordinate_system ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/data_region.cc b/CarpetDev/CarpetIOF5/src/data_region.cc
index bee5a070c..7a68a66b9 100644
--- a/CarpetDev/CarpetIOF5/src/data_region.cc
+++ b/CarpetDev/CarpetIOF5/src/data_region.cc
@@ -8,7 +8,6 @@
 #include "carpet.hh"
 
 #include "data_region.hh"
-#include "utils.hh"
 
 
 
@@ -54,7 +53,8 @@ namespace CarpetIOF5 {
       
       m_dataset
         = H5Dcreate (m_tensor_component.get_hdf5_tensor_component(), name,
-                     hdf5_datatype, m_dataspace, m_properties);
+                     hdf5_datatype, m_dataspace,
+                     H5P_DEFAULT, m_properties, H5P_DEFAULT);
       assert (m_dataset >= 0);
       
       write_or_check_attribute
@@ -82,6 +82,21 @@ namespace CarpetIOF5 {
     
     
     
+    string data_region_t::
+    name_from_region (bbox<int, dim> const & region)
+    {
+      ostringstream namebuf;
+#if 0
+      namebuf << "map=" << Carpet::map << " "
+              << "region=" << region;
+#else
+      namebuf << "region=" << region;
+#endif
+      return namebuf.str();
+    }
+    
+    
+    
     tensor_component_t & data_region_t::
     get_tensor_component ()
       const
diff --git a/CarpetDev/CarpetIOF5/src/data_region.hh b/CarpetDev/CarpetIOF5/src/data_region.hh
index 9b354166a..d40a88e7e 100644
--- a/CarpetDev/CarpetIOF5/src/data_region.hh
+++ b/CarpetDev/CarpetIOF5/src/data_region.hh
@@ -36,6 +36,9 @@ namespace CarpetIOF5 {
       virtual
       ~ data_region_t ();
       
+      static string
+      name_from_region (bbox<int, dim> const & region);
+      
       tensor_component_t &
       get_tensor_component ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/file.cc b/CarpetDev/CarpetIOF5/src/file.cc
index bf6167e5a..55c00a124 100644
--- a/CarpetDev/CarpetIOF5/src/file.cc
+++ b/CarpetDev/CarpetIOF5/src/file.cc
@@ -1,4 +1,8 @@
+#include <algorithm>
 #include <cassert>
+#include <iomanip>
+#include <iostream>
+#include <sstream>
 #include <string>
 
 #include <hdf5.h>
@@ -13,16 +17,27 @@ namespace CarpetIOF5 {
   
   namespace F5 {
     
+    using namespace std;
+    
     file_t::
     file_t (cGH const * const cctkGH,
-            string const filename,
+            string const basename,
+            string const extension,
+            bool const want_metafile,
             bool const do_truncate)
       : m_cctkGH (cctkGH),
-        m_filename (filename)
+        m_have_metafile (want_metafile),
+        m_basename (basename),
+        m_extension (extension)
     {
       assert (cctkGH);
       
-      char const * const filenameptr = filename.c_str();
+      int const proc = CCTK_MyProc (cctkGH);
+      m_metafilename = make_metafilename ();
+      m_filename = make_filename (proc);
+      
+      char const * const metafilenameptr = m_metafilename.c_str();
+      char const * const filenameptr = m_filename.c_str();
       
       htri_t is_hdf5;
       H5E_BEGIN_TRY {
@@ -30,16 +45,34 @@ namespace CarpetIOF5 {
       } H5E_END_TRY;
       bool const file_exists = is_hdf5 > 0;
       
+      // Ignore the metafile when determining whether the file already
+      // exists
       if (do_truncate or not file_exists)
       {
+        m_hdf5_metafile = -1;
+        if (m_have_metafile)
+        {
+          m_hdf5_metafile
+            = H5Fcreate (metafilenameptr,
+                         H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+        }
         m_hdf5_file
           = H5Fcreate (filenameptr, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
       }
       else
       {
+        m_hdf5_metafile = -1;
+        if (m_have_metafile)
+        {
+          m_hdf5_metafile
+            = H5Fopen (metafilenameptr, H5F_ACC_RDWR, H5P_DEFAULT);
+        }
         m_hdf5_file = H5Fopen (filenameptr, H5F_ACC_RDWR, H5P_DEFAULT);
       }
       
+      m_filenames.resize (CCTK_nProcs (cctkGH));
+      m_filenames.at(proc) = m_filename;
+      
       assert (invariant());
     }
     
@@ -48,12 +81,56 @@ namespace CarpetIOF5 {
     file_t::
     ~ file_t()
     {
+      if (m_have_metafile)
+      {
+        herr_t const herr = H5Fclose (m_hdf5_metafile);
+        assert (not herr);
+      }
       herr_t const herr = H5Fclose (m_hdf5_file);
       assert (not herr);
     }
     
     
     
+    int file_t::
+    base_10_digits (int number)
+    {
+      number = abs (number);
+      int digits = 1;
+      while (number >= 10)
+      {
+        number /= 10;
+        ++ digits;
+      }
+      return digits;
+    }
+    
+    
+    
+    string file_t::
+    make_metafilename ()
+      const
+    {
+      return m_basename + m_extension;
+    }
+    
+    
+    
+    string file_t::
+    make_filename (int const proc)
+      const
+    {
+      int const digits = base_10_digits (CCTK_nProcs (m_cctkGH) - 1);
+      ostringstream filenamebuf;
+      filenamebuf << m_basename
+                  << "."
+                  << setw (digits) << setfill ('0') << proc
+                  << m_extension;
+      return filenamebuf.str();
+    }
+    
+    
+    
     cGH const * file_t::
     get_cctkGH ()
       const
@@ -63,6 +140,38 @@ namespace CarpetIOF5 {
     
     
     
+    bool file_t::
+    get_have_metafile ()
+      const
+    {
+      return m_have_metafile;
+    }
+    
+    
+    
+    string file_t::
+    get_filename (int const proc)
+      const
+    {
+      assert (proc >= 0 and proc < CCTK_nProcs (m_cctkGH));
+      if (m_filenames.at(proc).empty())
+      {
+        m_filenames.at(proc) = make_filename (proc);
+      }
+      return m_filenames.at(proc);
+    }
+    
+    
+    
+    hid_t file_t::
+    get_hdf5_metafile()
+      const
+    {
+      return m_hdf5_metafile;
+    }
+    
+    
+    
     hid_t file_t::
     get_hdf5_file()
       const
@@ -72,11 +181,32 @@ namespace CarpetIOF5 {
     
     
     
+    void file_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        l_filename = m_filename;
+        l_objectname = string ("");
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool file_t::
     invariant()
       const
     {
       return (m_cctkGH != 0
+              and (not m_have_metafile or m_hdf5_metafile >= 0)
               and m_hdf5_file >= 0);
     }
     
diff --git a/CarpetDev/CarpetIOF5/src/file.hh b/CarpetDev/CarpetIOF5/src/file.hh
index b5ac2d696..66d9f0334 100644
--- a/CarpetDev/CarpetIOF5/src/file.hh
+++ b/CarpetDev/CarpetIOF5/src/file.hh
@@ -2,6 +2,7 @@
 #define FILE_HH
 
 #include <string>
+#include <vector>
 
 #include <hdf5.h>
 
@@ -14,6 +15,7 @@
 namespace CarpetIOF5 {
   
   using std::string;
+  using std::vector;
   
   
   
@@ -23,18 +25,40 @@ namespace CarpetIOF5 {
       
       cGH const * const m_cctkGH;
       
-      string const m_filename;
+      bool const m_have_metafile;
       
+      string const m_basename;
+      string const m_extension;
+      
+      string m_metafilename;
+      string m_filename;
+      
+      mutable vector <string> m_filenames;
+      
+      hid_t m_hdf5_metafile;
       hid_t m_hdf5_file;
       
       file_t ();
       file_t (file_t const &);
       file_t operator= (file_t const &);
       
+      static int
+      base_10_digits (int number);
+      
+      string
+      make_metafilename ()
+        const;
+      
+      string
+      make_filename (int proc)
+        const;
+      
     public:
       
       file_t (cGH const * cctkGH,
               string filename,
+              string extension,
+              bool want_metafile,
               bool do_truncate);
       
       virtual
@@ -44,10 +68,27 @@ namespace CarpetIOF5 {
       get_cctkGH ()
         const;
       
+      bool
+      get_have_metafile ()
+        const;
+      
+      string
+      get_filename (int proc)
+        const;
+      
+      hid_t
+      get_hdf5_metafile ()
+        const;
+      
       hid_t
       get_hdf5_file ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/make.code.defn b/CarpetDev/CarpetIOF5/src/make.code.defn
index d0a45f9d8..0641b4f9d 100644
--- a/CarpetDev/CarpetIOF5/src/make.code.defn
+++ b/CarpetDev/CarpetIOF5/src/make.code.defn
@@ -6,6 +6,7 @@ SRCS =	IOF5.cc					\
 	data_region.cc				\
         extending.cc				\
         file.cc					\
+	meta_data_region.cc			\
         physical_quantity.cc 			\
         simulation.cc 				\
         tensor_component.cc			\
diff --git a/CarpetDev/CarpetIOF5/src/meta_data_region.cc b/CarpetDev/CarpetIOF5/src/meta_data_region.cc
new file mode 100644
index 000000000..4f32e33a2
--- /dev/null
+++ b/CarpetDev/CarpetIOF5/src/meta_data_region.cc
@@ -0,0 +1,90 @@
+#include <cassert>
+#include <cstdlib>
+#include <sstream>
+#include <string>
+
+#include "cctk.h"
+
+#include "carpet.hh"
+
+#include "data_region.hh"
+#include "meta_data_region.hh"
+#include "utils.hh"
+
+
+
+namespace CarpetIOF5 {
+  
+  namespace F5 {
+    
+    using std::ostringstream;
+    
+    
+    
+    meta_data_region_t::
+    meta_data_region_t (tensor_component_t & tensor_component,
+                        bbox<int, dim> const & region)
+      : m_tensor_component (tensor_component),
+        m_region (region)
+    {
+      assert (not region.empty());
+      
+      string const namestr = data_region_t::name_from_region (region);
+      char const * const name = namestr.c_str();
+      assert (name != 0);
+      
+      assert (invariant());
+    }
+    
+    
+    
+    meta_data_region_t::
+    ~ meta_data_region_t ()
+    {
+    }
+    
+    
+    
+    tensor_component_t & meta_data_region_t::
+    get_tensor_component ()
+      const
+    {
+      return m_tensor_component;
+    }
+    
+    
+    
+    void meta_data_region_t::
+    write (int const proc)
+      const
+    {
+      string filename;
+      string objectname;
+      get_tensor_component().get_link_destination (filename, objectname);
+      
+      string const name = data_region_t::name_from_region (m_region);
+      
+      hid_t const hdf5_tensor_component
+        = m_tensor_component.get_hdf5_tensor_component();
+      
+      herr_t const herr
+        = H5Lcreate_external(filename.c_str(),
+                             objectname.c_str(),
+                             hdf5_tensor_component,
+                             name.c_str(),
+                             H5P_DEFAULT, H5P_DEFAULT);
+      assert (not herr);
+    }
+    
+    
+    
+    bool meta_data_region_t::
+    invariant ()
+      const
+    {
+      return not m_region.empty();
+    }
+    
+  } // namespace F5
+
+} // namespace CarpetIOF5
diff --git a/CarpetDev/CarpetIOF5/src/meta_data_region.hh b/CarpetDev/CarpetIOF5/src/meta_data_region.hh
new file mode 100644
index 000000000..b109c5da4
--- /dev/null
+++ b/CarpetDev/CarpetIOF5/src/meta_data_region.hh
@@ -0,0 +1,57 @@
+#ifndef META_DATA_REGION_HH
+#define META_DATA_REGION_HH
+
+#include <hdf5.h>
+
+#include "bbox.hh"
+#include "defs.hh"
+
+#include "tensor_component.hh"
+
+
+
+namespace CarpetIOF5 {
+  
+  namespace F5 {
+    
+    class meta_data_region_t {
+      
+      tensor_component_t & m_tensor_component;
+      
+      bbox<int, dim> const m_region;
+      
+      hid_t m_properties;
+      hid_t m_dataset;
+      hid_t m_dataspace;
+      
+      meta_data_region_t ();
+      meta_data_region_t (meta_data_region_t const &);
+      meta_data_region_t operator= (meta_data_region_t const &);
+      
+    public:
+      
+      meta_data_region_t (tensor_component_t & tensor_component,
+                          bbox<int, dim> const & region);
+      
+      virtual
+      ~ meta_data_region_t ();
+      
+      tensor_component_t &
+      get_tensor_component ()
+        const;
+      
+      void
+      write (int proc)
+        const;
+      
+      virtual bool
+      invariant ()
+        const;
+      
+    };
+    
+  } // namespace F5
+
+} // namespace CarpetIOF5
+
+#endif  // #ifndef META_DATA_REGION_HH
diff --git a/CarpetDev/CarpetIOF5/src/physical_quantity.cc b/CarpetDev/CarpetIOF5/src/physical_quantity.cc
index 2c4a24d65..0b6720ece 100644
--- a/CarpetDev/CarpetIOF5/src/physical_quantity.cc
+++ b/CarpetDev/CarpetIOF5/src/physical_quantity.cc
@@ -4,7 +4,6 @@
 #include "cctk.h"
 
 #include "physical_quantity.hh"
-#include "utils.hh"
 
 
 
@@ -26,6 +25,7 @@ namespace CarpetIOF5 {
       {
         * p = static_cast<char> (tolower (* p));
       }
+      m_name = string (name);
       
       m_hdf5_physical_quantity
         = open_or_create_group (m_coordinate_system
@@ -76,6 +76,26 @@ namespace CarpetIOF5 {
     
     
     
+    void physical_quantity_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_coordinate_system().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool physical_quantity_t::
     invariant ()
       const
diff --git a/CarpetDev/CarpetIOF5/src/physical_quantity.hh b/CarpetDev/CarpetIOF5/src/physical_quantity.hh
index 56f768799..38b670cb2 100644
--- a/CarpetDev/CarpetIOF5/src/physical_quantity.hh
+++ b/CarpetDev/CarpetIOF5/src/physical_quantity.hh
@@ -16,6 +16,7 @@ namespace CarpetIOF5 {
       coordinate_system_t & m_coordinate_system;
       
       int const m_group;
+      string m_name;
       
       hid_t m_hdf5_physical_quantity;
       
@@ -43,6 +44,11 @@ namespace CarpetIOF5 {
       get_hdf5_physical_quantity ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/simulation.cc b/CarpetDev/CarpetIOF5/src/simulation.cc
index 10441b498..98a0a3888 100644
--- a/CarpetDev/CarpetIOF5/src/simulation.cc
+++ b/CarpetDev/CarpetIOF5/src/simulation.cc
@@ -60,6 +60,26 @@ namespace CarpetIOF5 {
     
     
     
+    void simulation_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_timestep().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool simulation_t::
     invariant()
       const
diff --git a/CarpetDev/CarpetIOF5/src/simulation.hh b/CarpetDev/CarpetIOF5/src/simulation.hh
index 7aed7ca11..272b3385c 100644
--- a/CarpetDev/CarpetIOF5/src/simulation.hh
+++ b/CarpetDev/CarpetIOF5/src/simulation.hh
@@ -46,6 +46,11 @@ namespace CarpetIOF5 {
       get_hdf5_simulation ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/tensor_component.cc b/CarpetDev/CarpetIOF5/src/tensor_component.cc
index c1575f232..5d4b281fc 100644
--- a/CarpetDev/CarpetIOF5/src/tensor_component.cc
+++ b/CarpetDev/CarpetIOF5/src/tensor_component.cc
@@ -4,7 +4,6 @@
 #include "cctk.h"
 
 #include "tensor_component.hh"
-#include "utils.hh"
 
 
 
@@ -22,6 +21,7 @@ namespace CarpetIOF5 {
       
       char const * const name = CCTK_VarName (variable);
       assert (name != 0);
+      m_name = string (name);
       
       m_hdf5_tensor_component
         = open_or_create_group (m_physical_quantity
@@ -70,6 +70,26 @@ namespace CarpetIOF5 {
     
     
     
+    void tensor_component_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_physical_quantity().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool tensor_component_t::
     invariant ()
       const
diff --git a/CarpetDev/CarpetIOF5/src/tensor_component.hh b/CarpetDev/CarpetIOF5/src/tensor_component.hh
index 8377983a7..f659c0076 100644
--- a/CarpetDev/CarpetIOF5/src/tensor_component.hh
+++ b/CarpetDev/CarpetIOF5/src/tensor_component.hh
@@ -4,6 +4,7 @@
 #include <hdf5.h>
 
 #include "physical_quantity.hh"
+#include "utils.hh"
 
 
 
@@ -16,6 +17,7 @@ namespace CarpetIOF5 {
       physical_quantity_t & m_physical_quantity;
       
       int const m_variable;
+      string m_name;
       
       hid_t m_hdf5_tensor_component;
       
@@ -43,6 +45,11 @@ namespace CarpetIOF5 {
       get_hdf5_tensor_component ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/timestep.cc b/CarpetDev/CarpetIOF5/src/timestep.cc
index e7b75c4fe..73d106a92 100644
--- a/CarpetDev/CarpetIOF5/src/timestep.cc
+++ b/CarpetDev/CarpetIOF5/src/timestep.cc
@@ -99,6 +99,26 @@ namespace CarpetIOF5 {
     
     
     
+    void timestep_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_file().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool timestep_t::
     invariant()
       const
diff --git a/CarpetDev/CarpetIOF5/src/timestep.hh b/CarpetDev/CarpetIOF5/src/timestep.hh
index 203cb6683..3a44ec29b 100644
--- a/CarpetDev/CarpetIOF5/src/timestep.hh
+++ b/CarpetDev/CarpetIOF5/src/timestep.hh
@@ -52,6 +52,11 @@ namespace CarpetIOF5 {
       get_hdf5_timestep ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/topology.cc b/CarpetDev/CarpetIOF5/src/topology.cc
index a3558448e..401f65271 100644
--- a/CarpetDev/CarpetIOF5/src/topology.cc
+++ b/CarpetDev/CarpetIOF5/src/topology.cc
@@ -9,7 +9,6 @@
 #include "vect.hh"
 
 #include "topology.hh"
-#include "utils.hh"
 
 
 
@@ -64,6 +63,7 @@ namespace CarpetIOF5 {
       : topology_t (simulation)
     {
       char const * const name = "Vertices";
+      m_name = string (name);
       m_hdf5_topology
         = open_or_create_group (m_simulation.get_hdf5_simulation(), name);
       assert (m_hdf5_topology >= 0);
@@ -112,6 +112,7 @@ namespace CarpetIOF5 {
       ostringstream namebuf;
       namebuf << "Vertices map=" << map << " level=" << refinement_level;
       string const namestr = namebuf.str();
+      m_name = namestr;
       char const * const name = namestr.c_str();
       
       m_hdf5_topology
@@ -155,6 +156,26 @@ namespace CarpetIOF5 {
     
     
     
+    void topology_t::
+    get_link_destination (string & filename,
+                          string & objectname)
+      const
+    {
+      static bool initialised = false;
+      static string l_filename;
+      static string l_objectname;
+      if (not initialised)
+      {
+        initialised = true;
+        get_simulation().get_link_destination (l_filename, l_objectname);
+        l_objectname += string ("/") + m_name;
+      }
+      filename = l_filename;
+      objectname = l_objectname;
+    }
+    
+    
+    
     bool mesh_refinement_topology_t::
     invariant()
       const
diff --git a/CarpetDev/CarpetIOF5/src/topology.hh b/CarpetDev/CarpetIOF5/src/topology.hh
index 2e97ff255..df841107b 100644
--- a/CarpetDev/CarpetIOF5/src/topology.hh
+++ b/CarpetDev/CarpetIOF5/src/topology.hh
@@ -9,6 +9,7 @@
 #include "vect.hh"
 
 #include "simulation.hh"
+#include "utils.hh"
 
 
 
@@ -26,6 +27,8 @@ namespace CarpetIOF5 {
       
       simulation_t & m_simulation;
       
+      string m_name;
+      
       hid_t m_hdf5_topology;
       
       topology_t (simulation_t & simulation);
@@ -41,6 +44,11 @@ namespace CarpetIOF5 {
       get_simulation ()
         const;
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       hid_t
       get_hdf5_topology ()
         const;
@@ -106,6 +114,11 @@ namespace CarpetIOF5 {
       virtual
       ~ mesh_refinement_topology_t ();
       
+      void
+      get_link_destination (string & filename,
+                            string & objectname)
+        const;
+      
       virtual bool
       invariant ()
         const;
diff --git a/CarpetDev/CarpetIOF5/src/utils.cc b/CarpetDev/CarpetIOF5/src/utils.cc
index 6bad1510a..b1efb21ed 100644
--- a/CarpetDev/CarpetIOF5/src/utils.cc
+++ b/CarpetDev/CarpetIOF5/src/utils.cc
@@ -108,12 +108,10 @@ namespace CarpetIOF5 {
       {
         initialised = true;
         
-        hsize_t const cdim = 2;
-        int const perm = 0;
+        hsize_t const cdim[1] = { 2 };
         
         hdf_complex_datatype
-          = H5Tarray_create (hdf5_datatype_from_dummy (real),
-                             1, & cdim, & perm);
+          = H5Tarray_create (hdf5_datatype_from_dummy (real), 1, cdim);
         assert (hdf_complex_datatype >= 0);
       }
       
@@ -197,11 +195,11 @@ namespace CarpetIOF5 {
       hid_t group;
       if (group_exists)
       {
-        group = H5Gopen (where, name);
+        group = H5Gopen (where, name, H5P_DEFAULT);
       }
       else
       {
-        group = H5Gcreate (where, name, 0);
+        group = H5Gcreate (where, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
       }
       
       return group;
@@ -235,7 +233,8 @@ namespace CarpetIOF5 {
         hsize_t const adim = num_values;
         hid_t const dataspace = H5Screate_simple (1, & adim, & adim);
         assert (dataspace >= 0);
-        attribute = H5Acreate (where, name, datatype, dataspace, H5P_DEFAULT);
+        attribute = H5Acreate (where, name, datatype, dataspace,
+                               H5P_DEFAULT, H5P_DEFAULT);
         assert (attribute >= 0);
         herr_t herr;
         herr = H5Awrite (attribute, datatype, values);
@@ -257,7 +256,7 @@ namespace CarpetIOF5 {
         hsize_t adim;
         herr_t herr;
         herr = H5Sget_simple_extent_dims (dataspace, & adim, 0);
-        assert (adim == num_values);
+        assert (adim == hsize_t (num_values));
         vector<T> buf (adim);
         herr = H5Aread (attribute, datatype, & buf.front());
         assert (not herr);
@@ -386,7 +385,8 @@ namespace CarpetIOF5 {
         hsize_t const dim = 1;
         hid_t const dataspace = H5Screate_simple (1, & dim, & dim);
         assert (dataspace >= 0);
-        attribute = H5Acreate (where, name, datatype, dataspace, H5P_DEFAULT);
+        attribute = H5Acreate (where, name, datatype, dataspace,
+                               H5P_DEFAULT, H5P_DEFAULT);
         assert (attribute >= 0);
         herr = H5Awrite (attribute, datatype, value);
         assert (not herr);
@@ -428,7 +428,7 @@ namespace CarpetIOF5 {
         assert (strcmp (& buf.front(), value) == 0);
       }
     }
-
+    
   } // namespace F5
 
 } // namespace CarpetIOF5
diff --git a/CarpetDev/CarpetIOF5/src/utils.hh b/CarpetDev/CarpetIOF5/src/utils.hh
index 0c7869b68..c379cc775 100644
--- a/CarpetDev/CarpetIOF5/src/utils.hh
+++ b/CarpetDev/CarpetIOF5/src/utils.hh
@@ -1,5 +1,5 @@
-#ifndef utils_HH
-#define utils_HH
+#ifndef UTILS_HH
+#define UTILS_HH
 
 #include <hdf5.h>
 
diff --git a/CarpetDev/CarpetIOF5/src/writer.cc b/CarpetDev/CarpetIOF5/src/writer.cc
index f7aa3d05a..e4ef100f6 100644
--- a/CarpetDev/CarpetIOF5/src/writer.cc
+++ b/CarpetDev/CarpetIOF5/src/writer.cc
@@ -8,6 +8,7 @@
 
 #include "data_region.hh"
 #include "file.hh"
+#include "meta_data_region.hh"
 #include "simulation.hh"
 #include "tensor_component.hh"
 #include "timestep.hh"
@@ -32,13 +33,14 @@ namespace CarpetIOF5 {
   write (F5::file_t & file)
     const
   {
-    write_meta (file);
+    write_meta (file, file.get_have_metafile());
   }
   
   
   
   void writer_t::
-  write_meta (F5::file_t & file)
+  write_meta (F5::file_t & file,
+              bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -57,19 +59,20 @@ namespace CarpetIOF5 {
            not mglevel_iter.done();
            mglevel_iter.step())
       {
-        write_one_mglevel (timestep);
+        write_one_mglevel (timestep, have_metafile);
       }
     }
     else
     {
-      write_one_mglevel (timestep);
+      write_one_mglevel (timestep, have_metafile);
     }
   }
   
   
   
   void writer_t::
-  write_one_mglevel (F5::timestep_t & timestep)
+  write_one_mglevel (F5::timestep_t & timestep,
+                     bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -96,7 +99,7 @@ namespace CarpetIOF5 {
       {
         if (Carpet::do_global_mode)
         {
-          write_global (simulation);
+          write_global (simulation, have_metafile);
         }
       }
       break;
@@ -108,12 +111,12 @@ namespace CarpetIOF5 {
                not reflevel_iter.done();
                reflevel_iter.step())
           {
-            write_one_reflevel (simulation);
+            write_one_reflevel (simulation, have_metafile);
           }
         }
         else
         {
-          write_one_reflevel (simulation);
+          write_one_reflevel (simulation, have_metafile);
         }
       }
       break;
@@ -125,7 +128,8 @@ namespace CarpetIOF5 {
   
   
   void writer_t::
-  write_global (F5::simulation_t & simulation)
+  write_global (F5::simulation_t & simulation,
+                bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -163,8 +167,15 @@ namespace CarpetIOF5 {
     bbox<int, dim> const & region
       = dd->boxes.at(Carpet::mglevel).at(reflevel).at(myproc).exterior;
     
-    F5::data_region_t data_region (tensor_component, region);
+    if (have_metafile)
+    {
+      F5::meta_data_region_t meta_data_region (tensor_component, region);
+      gh * const hh = Carpet::vhh.at(Carpet::map);
+      int const proc = hh->processor (Carpet::reflevel, Carpet::component);
+      meta_data_region.write (proc);
+    }
     
+    F5::data_region_t data_region (tensor_component, region);
     int const timelevel = 0;
     void const * const varptr
       = CCTK_VarDataPtrI (m_cctkGH, timelevel, m_variable);
@@ -177,7 +188,8 @@ namespace CarpetIOF5 {
   
   
   void writer_t::
-  write_one_reflevel (F5::simulation_t & simulation)
+  write_one_reflevel (F5::simulation_t & simulation,
+                      bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -199,19 +211,20 @@ namespace CarpetIOF5 {
            not map_iter.done();
            map_iter.step())
       {
-        write_one_map (simulation);
+        write_one_map (simulation, have_metafile);
       }
     }
     else
     {
-      write_one_map (simulation);
+      write_one_map (simulation, have_metafile);
     }
   }
   
   
   
   void writer_t::
-  write_one_map (F5::simulation_t & simulation)
+  write_one_map (F5::simulation_t & simulation,
+                 bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -252,19 +265,20 @@ namespace CarpetIOF5 {
            not component_iter.done();
            component_iter.step())
       {
-        write_one_component (tensor_component);
+        write_one_component (tensor_component, have_metafile);
       }
     }
     else
     {
-      write_one_component (tensor_component);
+      write_one_component (tensor_component, have_metafile);
     }
   }
   
   
   
   void writer_t::
-  write_one_component (F5::tensor_component_t & tensor_component)
+  write_one_component (F5::tensor_component_t & tensor_component,
+                       bool const have_metafile)
     const
   {
     DECLARE_CCTK_PARAMETERS;
@@ -277,22 +291,32 @@ namespace CarpetIOF5 {
     }
     
     gh * const hh = Carpet::vhh.at(Carpet::map);
-    if (hh->is_local (Carpet::reflevel, Carpet::component))
+    bool const is_local = hh->is_local (Carpet::reflevel, Carpet::component);
+    if (have_metafile or is_local)
     {
       dh * const dd = Carpet::vdd.at(Carpet::map);
       bbox<int, dim> const & region
         = (dd->boxes.at(Carpet::mglevel).at(Carpet::reflevel)
            .at(Carpet::component).exterior);
       
-      F5::data_region_t data_region (tensor_component, region);
+      if (have_metafile)
+      {
+        F5::meta_data_region_t meta_data_region (tensor_component, region);
+        int const proc = hh->processor (Carpet::reflevel, Carpet::component);
+        meta_data_region.write (proc);
+      }
       
-      int const timelevel = 0;
-      void const * const varptr
-        = CCTK_VarDataPtrI (m_cctkGH, timelevel, m_variable);
-      assert (varptr != 0);
-      int const vartype = CCTK_VarTypeI (m_variable);
-      assert (vartype >= 0);
-      data_region.write (varptr, vartype);
+      if (is_local)
+      {
+        F5::data_region_t data_region (tensor_component, region);
+        int const timelevel = 0;
+        void const * const varptr
+          = CCTK_VarDataPtrI (m_cctkGH, timelevel, m_variable);
+        assert (varptr != 0);
+        int const vartype = CCTK_VarTypeI (m_variable);
+        assert (vartype >= 0);
+        data_region.write (varptr, vartype);
+      }
     }
   }
   
diff --git a/CarpetDev/CarpetIOF5/src/writer.hh b/CarpetDev/CarpetIOF5/src/writer.hh
index 8b8473f1e..056d39a3f 100644
--- a/CarpetDev/CarpetIOF5/src/writer.hh
+++ b/CarpetDev/CarpetIOF5/src/writer.hh
@@ -30,27 +30,33 @@ namespace CarpetIOF5 {
   private:
     
     void
-    write_meta (F5::file_t & file)
+    write_meta (F5::file_t & file,
+                bool have_metafile)
       const;
     
     void
-    write_one_mglevel (F5::timestep_t & timestep)
+    write_one_mglevel (F5::timestep_t & timestep,
+                       bool have_metafile)
       const;
     
     void
-    write_global (F5::simulation_t & simulation)
+    write_global (F5::simulation_t & simulation,
+                  bool have_metafile)
       const;
     
     void
-    write_one_reflevel (F5::simulation_t & simulation)
+    write_one_reflevel (F5::simulation_t & simulation,
+                        bool have_metafile)
       const;
     
     void
-    write_one_map (F5::simulation_t & simulation)
+    write_one_map (F5::simulation_t & simulation,
+                   bool have_metafile)
       const;
     
     void
-    write_one_component (F5::tensor_component_t & tensor_component)
+    write_one_component (F5::tensor_component_t & tensor_component,
+                         bool have_metafile)
       const;
     
   };