Switched IOPanda to use the new Hyperslabbing API for outputting arbitrary

hyperslabs.
You must update thorn CactusBase/IOUtil now.


git-svn-id: http://svn.cactuscode.org/arrangements/CactusPUGHIO/IOPanda/trunk@31 38c3d835-c875-442e-b0fe-21c19ce1d001

4 files changed, 347 insertions, 283 deletions

diff --git a/interface.ccl b/interface.ccl
index 015da7f..12dca79 100644
--- a/interface.ccl
+++ b/interface.ccl
@@ -2,4 +2,6 @@
 # $Header$
 
 implements: IOPanda
-inherits:   Hyperslab FlexIO
+inherits:   IO Hyperslab FlexIO
+
+USES INCLUDE HEADER: Hyperslab.h
diff --git a/src/Output.c b/src/Output.c
index 4bb6a86..467fd22 100644
--- a/src/Output.c
+++ b/src/Output.c
@@ -14,6 +14,7 @@
 
 #include "cctk.h"
 #include "cctk_Parameters.h"
+#include "Hyperslab.h"
 #include "CactusBase/IOUtil/src/ioGH.h"
 #include "CactusPUGH/PUGH/src/include/pugh.h"
 
@@ -28,13 +29,13 @@ CCTK_FILEVERSION(BetaThorns_IOPanda_Output_c)
 /********************************************************************
  ********************    Internal Routines   ************************
  ********************************************************************/
-static int CheckOutputVar (int vindex);
-static void CheckSteerableParameters (pandaGH *myGH);
-static void SetOutputFlag (int vindex, const char *optstring, void *arg);
-static int IOPanda_Timestep (const cGH *GH, int vindex, const char *alias);
-static void IOPanda_IEEEIOStructDump (const cGH *GH, const char *fname);
-static void IOPanda_AddCommonAttributes (const cGH *GH, int vindex, int timelevel, int global_size[3], char *fname);
-static void IOPanda_AddChunkAttributes (const cGH *GH, int vindex, CCTK_INT4 *geom, char *fname);
+static void CheckSteerableParameters (const cGH *GH);
+static int DumpVar (const cGH *GH, const ioRequest *request, const char *alias);
+static void IEEEIOStructDump (const cGH *GH, const char *fname);
+static void AddCommonAttributes (const cGH *GH, const ioRequest *request,
+                                 const char *fname);
+static void AddChunkAttributes (const cGH *GH, const ioRequest *request,
+                                const char *fname);
 
 
 /*@@
@@ -45,11 +46,12 @@ static void IOPanda_AddChunkAttributes (const cGH *GH, int vindex, CCTK_INT4 *ge
                Loops over all variables and outputs them if necessary
    @enddesc
 
-   @calls      IOPanda_TimeFor
-               IOPanda_Timestep
+   @calls      CheckSteerableParameters
+               IOPanda_TimeFor
+               IOPanda_OutputVarAs
 
    @var        GH
-   @vdesc      Pointer to CCTK GH
+   @vdesc      pointer to CCTK GH
    @vtype      const cGH *
    @vio        in
    @endvar
@@ -69,38 +71,36 @@ int IOPanda_OutputGH (const cGH *GH)
   DECLARE_CCTK_PARAMETERS
 
 
-  /* Get the GH extension for IOPanda */
-  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
-
-  CheckSteerableParameters (myGH);
+  CheckSteerableParameters (GH);
 
+  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
   if (myGH->out_every <= 0)
   {
     return (0);
   }
 
-  /* Loop over all variables */
+  /* loop over all variables */
   for (vindex = retval = 0; vindex < CCTK_NumVars (); vindex++)
   {
     if (IOPanda_TimeFor (GH, vindex))
     {
       name = CCTK_VarName (vindex);
+      fullname = CCTK_FullName (vindex);
 
       if (verbose)
       {
-        fullname = CCTK_FullName (vindex);
         CCTK_VInfo (CCTK_THORNSTRING, "IOPanda_OutputGH: "
                     "(fullname, name) = (%s, %s)", fullname, name);
-        free (fullname);
       }
 
-      /* Do the output */
-      if (IOPanda_Timestep (GH, vindex, name) == 0)
+      if (IOPanda_OutputVarAs (GH, fullname, name) == 0)
       {
-        /* Register variable as having output this iteration */
-        myGH->out_last [vindex] = GH->cctk_iteration;
+        /* register variable as having output this iteration */
+        myGH->out_last[vindex] = GH->cctk_iteration;
         retval++;
       }
+
+      free (fullname);
     }
   }
 
@@ -116,10 +116,12 @@ int IOPanda_OutputGH (const cGH *GH)
                Unconditional output of a variable using the IOPanda I/O method
    @enddesc
 
-   @calls      IOPanda_Timestep
+   @calls      IOUtil_ParseVarsForOutput
+               DumpVar
+               IOUtil_FreeIORequest
 
    @var        GH
-   @vdesc      Pointer to CCTK GH
+   @vdesc      pointer to CCTK GH
    @vtype      const cGH *
    @vio        in
    @endvar
@@ -137,25 +139,38 @@ int IOPanda_OutputGH (const cGH *GH)
 
    @returntype int
    @returndesc
-               return code of @seeroutine IOPanda_Timestep
+               return code of @seeroutine DumpVar
    @endreturndesc
 @@*/
 int IOPanda_OutputVarAs (const cGH *GH, const char *fullname, const char *alias)
 {
-  int vindex, retval;
+  int vindex, oneshot, retval;
+  const pandaGH *myGH;
   DECLARE_CCTK_PARAMETERS
 
 
   vindex = CCTK_VarIndex (fullname);
   if (verbose)
   {
-    CCTK_VInfo (CCTK_THORNSTRING, "IOPanda_OutputVarAs: "
-                "(fullname, alias, index) = (%s, %s, %d)",
-                fullname, alias, vindex);
+    CCTK_VInfo (CCTK_THORNSTRING, "IOPanda_OutputVarAs: (fullname, alias, "
+                "index) = (%s, %s, %d)", fullname, alias, vindex);
+  }
+
+  /* check whether the variable already has an I/O request entry */
+  myGH = (const pandaGH *) CCTK_GHExtension (GH, "IOPanda");
+  oneshot = myGH->requests[vindex] == NULL;
+  if (oneshot)
+  {
+    IOUtil_ParseVarsForOutput (GH, fullname, myGH->requests);
   }
 
-  /* Do the output */
-  retval = IOPanda_Timestep (GH, vindex, alias);
+  /* do the output */
+  retval = DumpVar (GH, myGH->requests[vindex], alias);
+
+  if (oneshot && myGH->requests[vindex])
+  {
+    IOUtil_FreeIORequest (&myGH->requests[vindex]);
+  }
 
   return (retval);
 }
@@ -173,7 +188,7 @@ int IOPanda_OutputVarAs (const cGH *GH, const char *fullname, const char *alias)
    @calls      CheckSteerableParameters
 
    @var        GH
-   @vdesc      Pointer to CCTK GH
+   @vdesc      pointer to CCTK GH
    @vtype      const cGH *
    @vio        in
    @endvar
@@ -191,39 +206,32 @@ int IOPanda_OutputVarAs (const cGH *GH, const char *fullname, const char *alias)
 @@*/
 int IOPanda_TimeFor (const cGH *GH, int vindex)
 {
-  pandaGH *myGH;
+  int retval;
+  const pandaGH *myGH;
   char *fullname;
 
 
-  /* Get the GH extension for IOPanda */
-  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
-
-  CheckSteerableParameters (myGH);
-
-  /* Check if any output was requested */
-  if (myGH->out_every <= 0)
-  {
-    return (0);
-  }
-
-  /* Check this variable should be output */
-  if (! (myGH->do_out[vindex] && GH->cctk_iteration % myGH->out_every == 0))
-  {
-    return (0);
-  }
+  CheckSteerableParameters (GH);
 
-  /* Check variable not already output this iteration */
-  if (myGH->out_last [vindex] == GH->cctk_iteration)
+  /* check if this variable should be output */
+  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
+  retval = myGH->out_every > 0 && myGH->requests[vindex] &&
+           GH->cctk_iteration % myGH->out_every == 0;
+  if (retval)
   {
-    fullname = CCTK_FullName (vindex);
-    CCTK_VWarn (5, __LINE__, __FILE__, CCTK_THORNSTRING,
-                "Already done IOPanda output for variable '%s' in current "
-                "iteration (probably via triggers)", fullname);
-    free (fullname);
-    return (0);
+    /* check if variable was not already output this iteration */
+    if (myGH->out_last[vindex] == GH->cctk_iteration)
+    {
+      fullname = CCTK_FullName (vindex);
+      CCTK_VWarn (6, __LINE__, __FILE__, CCTK_THORNSTRING,
+                  "Already done IOPanda output for variable '%s' in current "
+                  "iteration (probably via triggers)", fullname);
+      free (fullname);
+      retval = 0;
+    }
   }
 
-  return (1);
+  return (retval);
 }
 
 
@@ -235,10 +243,10 @@ int IOPanda_TimeFor (const cGH *GH, int vindex)
                Triggers the output a variable using the IOPanda output method
    @enddesc
 
-   @calls      IOPanda_Timestep
+   @calls      DumpVar
 
    @var        GH
-   @vdesc      Pointer to CCTK GH
+   @vdesc      pointer to CCTK GH
    @vtype      const cGH *
    @vio        in
    @endvar
@@ -250,35 +258,32 @@ int IOPanda_TimeFor (const cGH *GH, int vindex)
 
    @returntype int
    @returndesc
-               return code of @seeroutine IOPanda_Timestep
+               return code of @seeroutine DumpVar
    @endreturndesc
 @@*/
 int IOPanda_TriggerOutput (const cGH *GH, int vindex)
 {
   int retval;
-  pandaGH *myGH;
+  const pandaGH *myGH;
   const char *varname;
   DECLARE_CCTK_PARAMETERS
 
 
   varname = CCTK_VarName (vindex);
-
-  /* Get the GH extension for IOPanda */
-  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
-
   if (verbose)
   {
     CCTK_VInfo (CCTK_THORNSTRING, "TriggerOutput: "
                 "name, index = %s, %d", varname, vindex);
   }
 
-  /* Do the output */
-  retval = IOPanda_Timestep (GH, vindex, varname);
+  /* do the output */
+  myGH = (const pandaGH *) CCTK_GHExtension (GH, "IOPanda");
+  retval = DumpVar (GH, myGH->requests[vindex], varname);
 
   if (retval == 0)
   {
-    /* Register variable as having output this iteration */
-    myGH->out_last [vindex] = GH->cctk_iteration;
+    /* register variable as having output this iteration */
+    myGH->out_last[vindex] = GH->cctk_iteration;
   }
 
   return (retval);
@@ -297,22 +302,25 @@ int IOPanda_TriggerOutput (const cGH *GH, int vindex)
                and does appropriate re-evaluation.
    @enddesc
 
-   @calls      CCTK_TraverseString
+   @calls      IOUtil_ParseVarsForOutput
 
-   @var        myGH
-   @vdesc      Pointer to IOPanda GH
-   @vtype      pandaGH *
+   @var        GH
+   @vdesc      pointer to CCTK GH
+   @vtype      const cGH *
    @vio        in
    @endvar
 @@*/
-static void CheckSteerableParameters (pandaGH *myGH)
+static void CheckSteerableParameters (const cGH *GH)
 {
-  int times_set;
+  int vindex, times_set;
+  pandaGH *myGH;
+  char *fullname;
   static int out_vars_lastset = -1;
   DECLARE_CCTK_PARAMETERS
 
 
   /* how often to output */
+  myGH = (pandaGH *) CCTK_GHExtension (GH, "IOPanda");
   myGH->out_every = out_every;
   if (myGH->out_every < 0)
   {
@@ -325,77 +333,57 @@ static void CheckSteerableParameters (pandaGH *myGH)
   times_set = CCTK_ParameterQueryTimesSet ("out_vars", CCTK_THORNSTRING);
   if (times_set != out_vars_lastset)
   {
-    memset (myGH->do_out, 0, CCTK_NumVars ());
-    CCTK_TraverseString (out_vars, SetOutputFlag, myGH->do_out,
-                         CCTK_GROUP_OR_VAR);
-
-    /* Save the last setting of 'out_vars' parameter */
-    out_vars_lastset = times_set;
-  }
-}
-
-
-/* check if this variable can be output (static conditions) */
-static int CheckOutputVar (int vindex)
-{
-  char *errormsg, *fullname;
-
-
-  errormsg = NULL;
-
-/*** FIXME: IEEEIO doesn't provide a COMPLEX datatype
-            so somehow CCTK_COMPLEX has to be mapped onto REALs or so.
-            We have to check this already here because if an IEEEIO file
-            is created and nothing is written to, it crashes at re-opening. ***/
-  if (CCTK_VarTypeI (vindex) == CCTK_VARIABLE_COMPLEX)
-  {
-    errormsg = "IOPanda output for complex variable '%s' not yet supported";
-  }
-  else if (CCTK_GroupTypeFromVarI (vindex) == CCTK_SCALAR)
-  {
-    errormsg = "IOPanda output for scalar variable '%s' not supported";
-  }
-
-  if (errormsg)
-  {
-    fullname = CCTK_FullName (vindex);
-    CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
-                errormsg, fullname);
-    free (fullname);
-  }
-
-  return (errormsg != NULL);
-}
-
-
-/* callback for CCTK_TraverseString() to set the output flag
-   for the given variable */
-static void SetOutputFlag (int vindex, const char *optstring, void *arg)
-{
-  char *flags = (char *) arg;
-
+    IOUtil_ParseVarsForOutput (GH, out_vars, myGH->requests);
+
+    /*** FIXME: IEEEIO doesn't provide a COMPLEX datatype
+                so we should map CCTK_COMPLEX to two REALs here.
+                We have to check for this already here because if an IEEEIO file
+                is created and nothing is written to it, it will crash
+                at re-opening. ***/
+    for (vindex = CCTK_NumVars () - 1; vindex >= 0; vindex--)
+    {
+      if (! myGH->requests[vindex])
+      {
+        continue;
+      }
 
-  /* Check the variable type */
-  flags[vindex] = CheckOutputVar (vindex) == 0;
+      if (strncmp (CCTK_VarTypeName (vindex), "CCTK_VARIABLE_COMPLEX", 21))
+      {
+        fullname = CCTK_FullName (vindex);
+        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
+                    "IOPanda output for complex variable '%s' not yet "
+                    "supported", fullname);
+        free (fullname);
+        IOUtil_FreeIORequest (&myGH->requests[vindex]);
+      }
+      else if (CCTK_GroupTypeFromVarI (vindex) == CCTK_SCALAR ||
+               CCTK_GroupDimFromVarI (vindex) != 3)
+      {
+        fullname = CCTK_FullName (vindex);
+        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
+                    "IOPanda output for variable '%s' not supported (can only "
+                    "do 3D grid arrays)", fullname);
+        free (fullname);
+        IOUtil_FreeIORequest (&myGH->requests[vindex]);
+      }
+    }
 
-  if (optstring)
-  {
-    CCTK_VWarn (5, __LINE__, __FILE__, CCTK_THORNSTRING,
-                "Optional string '%s' in variable name ignored", optstring);
+    /* save the last setting of 'out_vars' parameter */
+    out_vars_lastset = times_set;
   }
 }
 
 
-static int IOPanda_Timestep (const cGH *GH, int vindex, const char *alias)
+static int DumpVar (const cGH *GH, const ioRequest *request, const char *alias)
 {
-  void *data;
-  int tmp[1], tmp1[3], tmp2[3];
+  void *hdata;
+  int tmp[1], tmp2[3];
   Distribution dist1[3], dist2[3];
-  CCTK_INT4 bnd[9];
-  int free_flag, timelevel;
+  int i, hdatasize, retval;
+  CCTK_INT mapping;
   ArrayInfo ainfo;
-  ioGH *ioUtilGH;
-  pGH *pughGH;
+  const ioGH *ioUtilGH;
+  const pGH *pughGH;
   char *fullname;
   union
   {
@@ -406,197 +394,262 @@ static int IOPanda_Timestep (const cGH *GH, int vindex, const char *alias)
 
 
   /* check if variable has storage assigned */
-  if (! CCTK_QueryGroupStorageI (GH, CCTK_GroupIndexFromVarI (vindex)))
+  if (! CCTK_QueryGroupStorageI (GH, CCTK_GroupIndexFromVarI (request->vindex)))
   {
-    fullname = CCTK_FullName (vindex);
+    fullname = CCTK_FullName (request->vindex);
     CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                 "No IOPanda output for '%s' (no storage)", fullname);
     free (fullname);
     return (-1);
   }
 
-  /* get the handles for PUGH and IOUtil GH extensions */
-  pughGH = PUGH_pGH (GH);
-  ioUtilGH = (ioGH *) CCTK_GHExtension (GH, "IO");
+  /* define the hyperslab mapping */
+  mapping = Hyperslab_DefineLocalMappingByIndex (GH, request->vindex,
+                                                 request->hdim,
+                                                 request->direction,
+                                                 request->origin,
+                                                 request->extent,
+                                                 request->downsample,
+                                                 -1, NULL,
+                                                 request->hsize_chunk,
+                                                 request->hsize,
+                                                 request->hoffset);
+  if (mapping < 0)
+  {
+    fullname = CCTK_FullName (request->vindex);
+    CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
+                "Failed to define hyperslab mapping for variable '%s'",
+                fullname);
+    free (fullname);
+    return (-1);
+  }
+
+  /* calculate the size of the hyperslab */
+  request->hsize_chunk[request->hdim] = 1;
+  for (i = 0; i < request->hdim; i++)
+  {
+    request->hsize_chunk[request->hdim] *= request->hsize_chunk[i];
+  }
+
+  /* get the hyperslab */
+  hdatasize = CCTK_VarTypeSize (request->hdatatype);
+  hdata = request->hsize_chunk[request->hdim] > 0 ?
+          malloc (request->hsize_chunk[request->hdim] * hdatasize) : NULL;
+  retval = Hyperslab_Get (GH, mapping, -1, request->vindex, request->timelevel,
+                          request->hdatatype, hdata);
+
+  /* release the mapping structure */
+  Hyperslab_FreeMapping (mapping);
+
+  if (retval)
+  {
+    fullname = CCTK_FullName (request->vindex);
+    CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
+                "Failed to extract hyperslab for variable '%s'", fullname);
+    free (fullname);
+    if (hdata)
+    {
+      free (hdata);
+    }
+    return (-2);
+  }
 
   /* prevent compiler warning "cast discards `const' from pointer target type"*/
   cast_to_const.const_char = alias;
   ainfo.name_ = cast_to_const.non_const_char;
 
-  ainfo.rank_ = 3;
-  tmp1[0] = GH->cctk_gsh[2];
-  tmp1[1] = GH->cctk_gsh[1];
-  tmp1[2] = GH->cctk_gsh[0];
-  ainfo.size_ = tmp1;
+  /* copy from CCTK_INT[] to int[] */
+  ainfo.size_ = (int *) malloc (request->hdim * sizeof (int));
+  for (ainfo.rank_ = 0; ainfo.rank_ < request->hdim; ainfo.rank_++)
+  {
+    ainfo.size_[ainfo.rank_] = request->hsize[i];
+  }
 
-  switch (CCTK_VarTypeI (vindex))
+  switch (request->hdatatype)
   {
-    case CCTK_VARIABLE_CHAR:
-      ainfo.esize_ = CHAR;
-      break;
+    case CCTK_VARIABLE_CHAR:   ainfo.esize_ = CHAR; break;
 
     case CCTK_VARIABLE_INT:
 #ifdef  CCTK_INTEGER_PRECISION_8
-      ainfo.esize_ = INT64;
+                               ainfo.esize_ = INT64; break;
 #elif   CCTK_INTEGER_PRECISION_4
-      ainfo.esize_ = INT32;
+                               ainfo.esize_ = INT32; break;
 #elif   CCTK_INTEGER_PRECISION_2
-      ainfo.esize_ = INT16;
+                               ainfo.esize_ = INT16; break;
 #endif
-      break;
 
     case CCTK_VARIABLE_REAL:
-      if (ioUtilGH->out_single)
-      {
-        ainfo.esize_ = FLOAT32;
-      }
-      else
-      {
-#ifdef  CCTK_REAL_PRECISION_8
-        ainfo.esize_ = FLOAT64;
-#elif   CCTK_REAL_PRECISION_4
-        ainfo.esize_ = FLOAT32;
+#ifdef  CCTK_REAL_PRECISION_4
+                               ainfo.esize_ = FLOAT32; break;
+#elif   CCTK_REAL_PRECISION_8
+                               ainfo.esize_ = FLOAT64; break;
 #endif
-      }
+
+#ifdef CCTK_INT2
+    case CCTK_VARIABLE_INT2:   ainfo.esize_ = INT16; break;
+#endif
+#ifdef CCTK_INT4
+    case CCTK_VARIABLE_INT4:   ainfo.esize_ = INT32; break;
+#endif
+#ifdef CCTK_INT8
+    case CCTK_VARIABLE_INT8:   ainfo.esize_ = INT64; break;
+#endif
+#ifdef CCTK_REAL4
+    case CCTK_VARIABLE_REAL4:  ainfo.esize_ = FLOAT32; break;
+#endif
+#ifdef CCTK_REAL8
+    case CCTK_VARIABLE_REAL8:  ainfo.esize_ = FLOAT64; break;
+#endif
+
+    default: CCTK_VWarn (0, __LINE__, __FILE__, CCTK_THORNSTRING, "Unsupported "
+                         "CCTK variable datatype %d", request->hdatatype);
+             break;
   }
 
   /* FIXME: rank */
   ainfo.mem_rank_ = 3;
-  tmp2[0] = pughGH->Connectivity [2]->nprocs [2];
-  tmp2[1] = pughGH->Connectivity [2]->nprocs [1];
-  tmp2[2] = pughGH->Connectivity [2]->nprocs [0];
+  pughGH = PUGH_pGH (GH);
+  tmp2[0] = pughGH->Connectivity[2]->nprocs[2];
+  tmp2[1] = pughGH->Connectivity[2]->nprocs[1];
+  tmp2[2] = pughGH->Connectivity[2]->nprocs[0];
   ainfo.mem_layout_ = tmp2;
   dist1[0] = dist1[1] = dist1[2] = BLOCK;
   ainfo.mem_dist_ = dist1;
 
   ainfo.disk_rank_ = 1;
   dist2[0] = BLOCK; dist2[1] = dist2[2] = NONE;
+  ioUtilGH = (const ioGH *) CCTK_GHExtension (GH, "IO");
   tmp[0]= ((CCTK_nProcs(GH) - 1) / ioUtilGH->ioproc_every + 1);
 
   ainfo.disk_layout_ = tmp;
   ainfo.disk_dist_ = dist2;
 
-  timelevel = 0;
-
-  IOPanda_getDumpData(GH, vindex, timelevel, &data, &free_flag, bnd, ainfo.esize_);
-  ainfo.data_ = (char *)data;
-
   /*** FIXME: asymmetric ghostzones */
-  ainfo.stencil_width_ = GH->cctk_nghostzones [0];
+  ainfo.stencil_width_ = GH->cctk_nghostzones[0];
+
+  ainfo.data_ = (char *) hdata;
 
   PandaTimestep(&ainfo);
-  if (free_flag)
+  if (hdata)
   {
-    free (data);
+    free (hdata);
   }
 
-  IOPanda_AddCommonAttributes(GH, vindex, timelevel, ainfo.size_, ainfo.name_);
+  AddCommonAttributes(GH, request, ainfo.name_);
 
   if (! ioUtilGH->unchunked)
   {
-    /* Write chunk attributes */
-    IOPanda_AddChunkAttributes (GH, vindex, bnd, ainfo.name_);
+    /* write chunk attributes */
+    AddChunkAttributes (GH, request, ainfo.name_);
   }
 
   if (PandaIsNewFile(ainfo.name_))
   {
-    IOPanda_IEEEIOStructDump(GH, ainfo.name_);
+    IEEEIOStructDump(GH, ainfo.name_);
   }
 
-  return (0);
+  return (retval);
 }
 
 
-static void IOPanda_AddCommonAttributes (const cGH *GH,
-                                         int vindex,
-                                         int timelevel,
-                                         int global_size[3],
-                                         char *fname)
+static void AddCommonAttributes (const cGH *GH, const ioRequest *request,
+                                 const char *fname)
 {
-  DECLARE_CCTK_PARAMETERS
-  CCTK_REAL d3_to_IO [6]; /* buffer for writing doubles to IEEEIO */
-  CCTK_INT4 i_to_IO;      /* buffer for writing an int to IEEEIO */
-  CCTK_INT4 i3_to_IO[3];  /* buffer for writing ints to IEEEIO */
-  CCTK_REAL dummy;
-  char *name, *gname;
-  ioGH *ioUtilGH;
+  int i;
+  char *name;
+  CCTK_INT4 *itmp;
+  CCTK_REAL *dtmp;
+  const ioGH *ioUtilGH;
+  char coord_system_name[20];
 
 
-  /* Get the handle for IO extensions */
-  ioUtilGH = (ioGH *) CCTK_GHExtension (GH, "IO");
+  itmp = (CCTK_INT4 *) malloc (request->hdim * sizeof (CCTK_INT4));
 
-  name = CCTK_FullName (vindex);
+  name = CCTK_FullName (request->vindex);
   Panda_WriteAttribute (fname, "name", BYTE, strlen (name) + 1, name);
   free (name);
 
-  gname = CCTK_GroupNameFromVarI (vindex);
-  Panda_WriteAttribute (fname, "groupname", BYTE, strlen (gname) + 1, gname);
-  free (gname);
+  name = CCTK_GroupNameFromVarI (request->vindex);
+  Panda_WriteAttribute (fname, "groupname", BYTE, strlen (name) + 1, name);
+  free (name);
 
-  i_to_IO = CCTK_GroupTypeFromVarI (vindex);
-  Panda_WriteAttribute (fname, "grouptype", INT32, 1, &i_to_IO);
+  itmp[0] = CCTK_GroupTypeFromVarI (request->vindex);
+  Panda_WriteAttribute (fname, "grouptype", INT32, 1, itmp);
 
-  i_to_IO = CCTK_NumTimeLevelsFromVarI (vindex);
-  Panda_WriteAttribute (fname, "ntimelevels", INT32, 1, &i_to_IO);
+  itmp[0] = CCTK_NumTimeLevelsFromVarI (request->vindex);
+  Panda_WriteAttribute (fname, "ntimelevels", INT32, 1, itmp);
 
-  i_to_IO = timelevel;
-  Panda_WriteAttribute (fname, "timelevel", INT32, 1, &i_to_IO);
+  itmp[0] = request->timelevel;
+  Panda_WriteAttribute (fname, "timelevel", INT32, 1, itmp);
 
-  Panda_WriteAttribute (fname, "time", FLOAT64, 1,&GH->cctk_time);
+  Panda_WriteAttribute (fname, "time", FLOAT64, 1, &GH->cctk_time);
 
-  d3_to_IO [0] = CCTK_CoordRange (GH, &d3_to_IO [0], &dummy, -1, "x", "cart3d");
-  d3_to_IO [1] = CCTK_CoordRange (GH, &d3_to_IO [1], &dummy, -1, "y", "cart3d");
-  d3_to_IO [2] = CCTK_CoordRange (GH, &d3_to_IO [2], &dummy, -1, "z", "cart3d");
-  Panda_WriteAttribute (fname, "origin", FLOAT64,3,d3_to_IO);
-  CCTK_CoordRange (GH, &d3_to_IO [0], &d3_to_IO [3], -1, "x", "cart3d");
-  CCTK_CoordRange (GH, &d3_to_IO [1], &d3_to_IO [4], -1, "y", "cart3d");
-  CCTK_CoordRange (GH, &d3_to_IO [2], &d3_to_IO [5], -1, "z", "cart3d");
-  Panda_WriteAttribute (fname, "min_ext", FLOAT64, 3, d3_to_IO);
-  Panda_WriteAttribute (fname, "max_ext", FLOAT64, 3, d3_to_IO+3);
+  /* attributes describing the underlying grid
+     These are only stored for CCTK_GF variables if they are associated
+     with coordinates. */
+  /* FIXME: This is hardcoded for cartesian coordinate systems.
+            A better solution would be to be able to query the coordinate
+            system which is associated with the variable. */
+  ioUtilGH = (ioGH *) CCTK_GHExtension (GH, "IO");
+  sprintf (coord_system_name, "cart%dd", request->hdim);
+  if (CCTK_GroupTypeFromVarI (request->vindex) == CCTK_GF &&
+      CCTK_CoordSystemHandle (coord_system_name) >= 0)
+  {
+    dtmp = (CCTK_REAL *) malloc (3 * request->hdim * sizeof (CCTK_REAL));
+    for (i = 0; i < request->hdim; i++)
+    {
+      CCTK_CoordRange (GH, &dtmp[i], &dtmp[i + request->hdim], i + 1,
+                       NULL, coord_system_name);
+      dtmp[i + 2*request->hdim] = GH->cctk_delta_space[i] *
+                                  ioUtilGH->downsample[i];
+    }
 
-  /* FIXME: dimension */
-  d3_to_IO [0] = GH->cctk_delta_space [0] * ioUtilGH->downsample[0];
-  d3_to_IO [1] = GH->cctk_delta_space [1] * ioUtilGH->downsample[1];
-  d3_to_IO [2] = GH->cctk_delta_space [2] * ioUtilGH->downsample[2];
-  Panda_WriteAttribute (fname, "delta", FLOAT64, 3, d3_to_IO);
+    Panda_WriteAttribute (fname, "origin", FLOAT64, request->hdim, dtmp);
+    Panda_WriteAttribute (fname, "min_ext", FLOAT64, request->hdim, dtmp);
+    Panda_WriteAttribute (fname, "max_ext", FLOAT64, request->hdim,
+                          dtmp + 1*request->hdim);
+    Panda_WriteAttribute (fname, "delta", FLOAT64, request->hdim,
+                          dtmp  + 2*request->hdim);
 
-  if (ioUtilGH->downsample[0] > 1 ||
-      ioUtilGH->downsample[1] > 1 ||
-      ioUtilGH->downsample[2] > 1)
+    if (ioUtilGH->downsample[0] > 1 ||
+        ioUtilGH->downsample[1] > 1 ||
+        ioUtilGH->downsample[2] > 1)
+    {
+      Panda_WriteAttribute (fname, "evolution_delta", FLOAT64, request->hdim,
+                            GH->cctk_delta_space);
+    }
+
+    free (dtmp);
+  }
+
+  for (i = 0; i < request->hdim; i++)
   {
-    d3_to_IO [0] = GH->cctk_delta_space [0];
-    d3_to_IO [1] = GH->cctk_delta_space [1];
-    d3_to_IO [2] = GH->cctk_delta_space [2];
-    Panda_WriteAttribute (fname, "evolution_delta", FLOAT64, 3, d3_to_IO);
+    itmp[i] = request->hsize[i];
   }
+  Panda_WriteAttribute (fname, "global_size", INT32, 3, itmp);
 
-  i3_to_IO[0] = global_size[0];
-  i3_to_IO[1] = global_size[1];
-  i3_to_IO[2] = global_size[2];
-  Panda_WriteAttribute (fname, "global_size", INT32, 3, i3_to_IO);
+  itmp[0] = CCTK_nProcs (GH);
+  Panda_WriteAttribute (fname, "nprocs", INT32, 1, itmp);
 
-  i_to_IO = CCTK_nProcs (GH);
-  Panda_WriteAttribute (fname, "nprocs", INT32, 1, &i_to_IO);
+  itmp[0] = ioUtilGH->ioproc_every;
+  Panda_WriteAttribute (fname, "ioproc_every", INT32, 1, itmp);
 
-  i_to_IO = ioUtilGH->ioproc_every;
-  Panda_WriteAttribute (fname, "ioproc_every", INT32, 1, &i_to_IO);
+  itmp[0] = ioUtilGH->unchunked;
+  Panda_WriteAttribute (fname, "unchunked", INT32, 1, itmp);
 
-  i_to_IO = ioUtilGH->unchunked;
-  Panda_WriteAttribute (fname, "unchunked", INT32, 1, &i_to_IO);
+  itmp[0] = GH->cctk_iteration;
+  Panda_WriteAttribute (fname, "iteration", INT32, 1, itmp);
 
-  i_to_IO = GH->cctk_iteration;
-  Panda_WriteAttribute (fname, "iteration", INT32, 1, &i_to_IO);
+  free (itmp);
 }
 
 
-static void IOPanda_AddChunkAttributes (const cGH *GH,
-                                        int vindex,
-                                        CCTK_INT4 *geom,
-                                        char *fname)
+static void AddChunkAttributes (const cGH *GH, const ioRequest *request,
+                                const char *fname)
 {
-  int dim;
-  char *name;
-  CCTK_INT4 i_to_IO;
+  int i;
+  char *fullname;
+  CCTK_INT4 *itmp;
 
 
   /* there is nothing to do for a serial run */
@@ -605,46 +658,53 @@ static void IOPanda_AddChunkAttributes (const cGH *GH,
     return;
   }
 
-  /* get the dimension of the variable */
-  dim = CCTK_GroupDimI (CCTK_GroupIndexFromVarI (vindex));
+  itmp = (CCTK_INT4 *) malloc (2 * request->hdim * sizeof (CCTK_INT4));
 
-  Panda_WriteAttribute (fname, "chunk_origin", INT32, dim, &geom[0]);
-  Panda_WriteAttribute (fname, "subchunk_lb", INT32, dim, &geom[0]);
-  Panda_WriteAttribute (fname, "global_size", INT32, dim, &geom[2*dim]);
+  /* copy from CCTK_INT[] to CCTK_INT4[] */
+  for (i = 0; i < request->hdim; i++)
+  {
+    itmp[0*request->hdim + i] = request->hoffset[i];
+    itmp[1*request->hdim + i] = request->hsize[i];
+  }
 
-  i_to_IO = GH->cctk_iteration;
-  Panda_WriteAttribute (fname, "chunk_dataset", INT32, 1, &i_to_IO);
+  Panda_WriteAttribute (fname, "chunk_origin", INT32, request->hdim, &itmp[0]);
+  Panda_WriteAttribute (fname, "subchunk_lb", INT32, request->hdim, &itmp[0]);
+  Panda_WriteAttribute (fname, "global_size", INT32, request->hdim,
+                        &itmp[request->hdim]);
 
-  name = CCTK_FullName (vindex);
-  Panda_WriteAttribute (fname, "name", CHAR, strlen (name)+1, name);
-  free (name);
+  itmp[0] = GH->cctk_iteration;
+  Panda_WriteAttribute (fname, "chunk_dataset", INT32, 1, itmp);
+
+  fullname = CCTK_FullName (request->vindex);
+  Panda_WriteAttribute (fname, "name", CHAR, strlen (fullname)+1, fullname);
+
+  free (fullname);
+  free (itmp);
 }
 
 
-static void IOPanda_IEEEIOStructDump (const cGH *GH,
-                                      const char *fname)
+static void IEEEIOStructDump (const cGH *GH, const char *fname)
 {
-  DECLARE_CCTK_PARAMETERS
   int len;
-  CCTK_INT4 i_temp;
-  CCTK_REAL d_temp;
-  ioGH *ioUtilGH;
+  CCTK_INT4 itmp;
+  CCTK_REAL dtmp;
+  const ioGH *ioUtilGH;
   char buffer[128];
+  DECLARE_CCTK_PARAMETERS
 
 
-  ioUtilGH = (ioGH *) CCTK_GHExtension (GH, "IO");
-
-  i_temp = GH->cctk_iteration;
-  Panda_WriteAttribute (fname, "GH$iteration", INT32, 1, &i_temp);
+  itmp = GH->cctk_iteration;
+  Panda_WriteAttribute (fname, "GH$iteration", INT32, 1, &itmp);
 
-  i_temp = ioUtilGH->ioproc_every;
-  Panda_WriteAttribute (fname, "GH$ioproc_every", INT32, 1, &i_temp);
+  ioUtilGH = (const ioGH *) CCTK_GHExtension (GH, "IO");
+  itmp = ioUtilGH->ioproc_every;
+  Panda_WriteAttribute (fname, "GH$ioproc_every", INT32, 1, &itmp);
 
-  i_temp = CCTK_nProcs (GH);
-  Panda_WriteAttribute (fname, "GH$nprocs", INT32, 1, &i_temp);
+  itmp = CCTK_nProcs (GH);
+  Panda_WriteAttribute (fname, "GH$nprocs", INT32, 1, &itmp);
 
-  d_temp = GH->cctk_time;
-  Panda_WriteAttribute (fname, "GH$time", FLOAT64, 1, &d_temp);
+  dtmp = GH->cctk_time;
+  Panda_WriteAttribute (fname, "GH$time", FLOAT64, 1, &dtmp);
 
   /* add the parameter filename and the creation date
      as file identification attributes */
diff --git a/src/Startup.c b/src/Startup.c
index 04a5fe6..d5f59c1 100644
--- a/src/Startup.c
+++ b/src/Startup.c
@@ -18,6 +18,7 @@
 #include "CactusBase/IOUtil/src/ioGH.h"
 #include "CactusBase/IOUtil/src/ioutil_Utils.h"
 #include "ioPandaGH.h"
+#include "Panda/c_interface.h"
 
 /* the rcs ID and its dummy function to use it */
 static const char *rcsid = "$Id$";
@@ -143,7 +144,7 @@ static void *SetupGH (tFleshConfig *config, int convergence_level, cGH *GH)
   /* allocate a new GH extension structure */
   myGH = (pandaGH *) malloc (sizeof (pandaGH));
   numvars = CCTK_NumVars ();
-  myGH->do_out = (char *) malloc (numvars * sizeof (char));
+  myGH->requests  = (ioRequest **) calloc (numvars, sizeof (ioRequest *));
   myGH->out_last = (int *) malloc (numvars * sizeof (int));
 
   for (i = 0; i < numvars; i++)
diff --git a/src/ioPandaGH.h b/src/ioPandaGH.h
index d066d37..7434e1f 100644
--- a/src/ioPandaGH.h
+++ b/src/ioPandaGH.h
@@ -12,15 +12,21 @@
 #define _IOPANDA_IOPANDAGH_H_ 1
 
 #include "StoreNamedData.h"
+#include "CactusBase/IOUtil/src/ioutil_Utils.h"
 
 
-typedef struct IOPandaGH
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+typedef struct
 {
   /* the number of times to output */
   int  out_every;
 
-  /* flags indicating output for variable[i] */
-  char *do_out;
+  /* I/O request descriptions for all CCTK variables */
+  ioRequest **requests;
 
   /* directory in which to output */
   char *outdir;
@@ -30,11 +36,6 @@ typedef struct IOPandaGH
 } pandaGH;
 
 
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
 /* prototypes of functions to be registered as IOPanda's IO method */
 int IOPanda_OutputGH (const cGH *GH);
 int IOPanda_TriggerOutput (const cGH *GH, int);