aboutsummaryrefslogtreecommitdiff
path: root/src/RestoreFile.c
blob: 1867caa318feaa11a3f0d5a9e3d6eee25848f8e3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
 /*@@
   @file      RestoreFile.c
   @date      Thu Jun 18 16:34:59 1998
   @author    Tom Goodale
   @desc
              Routines to restore grid variables from a given file
   @enddesc
   @version   $Id$
 @@*/

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

#include "cctk.h"
#include "cctk_Parameters.h"
#include "util_String.h"

#include "CactusPUGH/PUGH/src/include/pugh.h"
#include "CactusBase/IOUtil/src/ioGH.h"
#include "ioFlexGH.h"

/* the rcs ID and its dummy function to use it */
static const char *rcsid = "$Id$";
CCTK_FILEVERSION(CactusPUGHIO_IOFlexIO_RestoreFile_c)


/********************************************************************
 ********************    Macro Definitions   ************************
 ********************************************************************/
/* tag base for MPI messages */
#define STARTUPBASE 1001
/* The maximum number of dimensions we can deal with.
   There's no routine provided by the IEEEIO lib to query the number of
   dims from a dataset. */
#define MAXDIM      10


/********************************************************************
 ********************    Internal Routines   ************************
 ********************************************************************/
static int GetCommonAttributes (cGH *GH, IOFile fid, int unchunked, int *vindex,
                                int *grouptype, int *timelevel, int *iteration,
                                int has_version);
#ifdef CCTK_MPI
static int GetChunkAttributes (IOFile fid, int vindex);
#endif


/********************************************************************
 ********************    External Routines   ************************
 ********************************************************************/
int IOFlexIOi_RecoverVariables (cGH *GH, fileinfo_t *file);


 /*@@
   @routine    IOFlexIO_RecoverVariables
   @date       Fri Jun 19 09:19:48 1998
   @author     Tom Goodale
   @desc
               Reads in data from an IEEEIO file.
               The file has to be opened already, and the file layout
               determined (ioproc, ioproc_every, unchunked).
               This information is used to read the file and distribute
               the data among all processors.
   @enddesc

   @history
   @hauthor    Gabrielle Allen
   @hdate      Oct 17 1998
   @hdesc      Changed logic so that cactus stops if any of the dimensions of
               the input file and the current cactus run differ.
   @hauthor    Thomas Radke
   @hdate      May 05 1999
   @hdesc      Added parameter unchunked
   @endhistory

   @var        GH
   @vdesc      Pointer to CCTK grid hierarchy
   @vtype      cGH *
   @vio        in
   @endvar
   @var        file
   @vdesc      IEEEIO file info structure
   @vtype      fileinfo_t *
   @vio        in
   @endvar
@@*/
int IOFlexIOi_RecoverVariables (cGH *GH, fileinfo_t *file)
{
  int vindex, gtype, timelevel, iteration, myproc;
  int nDatasets, currentDataset;
  const ioGH *ioUtilGH;
  char *fullname;
#ifdef CCTK_MPI
  int i, proc, nprocs;
  const pGH *pughGH;
  pGExtras *extras;
  CCTK_INT info[3];
  int dim, npoints, vtype;
  void *buffer, *data;
  int *chunkdims, *chunkorigin;
  int element_size, flexio_type;
  MPI_Datatype mpi_type;
  MPI_Status ms;
#endif
  DECLARE_CCTK_PARAMETERS


  /* suppress compiler warnings about potentially uninitialized variables */
  nDatasets = 0;

  myproc = CCTK_MyProc (GH);
  ioUtilGH = CCTK_GHExtension (GH, "IO");

#ifdef CCTK_MPI
  pughGH = PUGH_pGH (GH);
  nprocs = CCTK_nProcs (GH);
#endif

  /* all I/O procs determine the number of datasets in their checkpoint files */
  if (myproc == file->ioproc)
  {
    /* get the number of sets */
    nDatasets = IOnDatasets (file->fid);
    if (CCTK_Equals (verbose, "full"))
    {
      CCTK_VInfo (CCTK_THORNSTRING, "  Input file has %d datasets", nDatasets);
    }
  }

  /* In Cactus 3.x we had only datasets containing grid function data.
     This distributed data was stored as one dataset per processor within
     the group belonging to one IO processor. So there should be
     nGF*ioproc_every datasets within each checkpoint file.

     This consistency condition is no longer true
     because now there might be datasets containing a SCALAR grouptype.
     These datasets are stored only from the IO processors,
     and they are just distributed to the non-IO processors again
     during recovery.

  if (nDatasets % file->ioproc_every != 0)
    CCTK_WARN (0, "Number of datasets isn't a multiple of nioprocs");
  */

  /* now process the datasets.
     All I/O processors read the datasets from their checkpoint file
     verify their contents and communicate them to the non-I/O processors. */

  /* at first the code for the I/O processors ... */
  if (myproc == file->ioproc)
  {
    /* seek here once to the beginning of the file, the file pointer
       is advanced then implicitely by subsequent calls to IOreadInfo() */
    FLEXIO_ERROR (IOseek (file->fid, 0));

    /* each IO processor loops over all available datasets, checks their
       consistency and broadcasts them to the non-IO processors */
    for (currentDataset = 0; currentDataset < nDatasets; currentDataset++)
    {
      /* read in the next dataset's attributes and verify them */
      if (GetCommonAttributes (GH, file->fid, file->unchunked, &vindex, &gtype,
                               &timelevel, &iteration, file->has_version) < 0)
      {
        CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                    "Ignoring dataset %d", currentDataset);
        continue;
      }

      /* if we read in initial data via the file reader interface
         check whether the user wants to have this variable restored */
      if (ioUtilGH->do_inVars && ioUtilGH->do_inVars[vindex] >= 0 &&
          ioUtilGH->do_inVars[vindex] != iteration + 1)
      {
        if (CCTK_Equals (verbose, "full"))
        {
          CCTK_VInfo (CCTK_THORNSTRING, "Ignoring dataset %d for file reader "
                      "recovery", currentDataset);
        }
        continue;
      }

      /* read in the data */
      if (CCTK_Equals (verbose, "full") ||
          (ioUtilGH->do_inVars && ! CCTK_Equals (verbose, "none")))
      {
        fullname = CCTK_FullName (vindex);
        CCTK_VInfo (CCTK_THORNSTRING, "    dataset %d: %s (timelevel %d, "
                    "cctk_iteration %d)",
                    currentDataset, fullname, timelevel, iteration);
        free (fullname);
      }

      if (file->ioproc_every == 1)
      {
        FLEXIO_ERROR (IOread (file->fid,
                              CCTK_VarDataPtrI (GH, timelevel, vindex)));
      }
#ifdef CCTK_MPI
      else
      {
        vtype = CCTK_VarTypeI (vindex);
        element_size = CCTK_VarTypeSize (vtype);
        mpi_type = PUGH_MPIDataType (pughGH, vtype);
        flexio_type = IOFlexIO_DataType (vtype);

        if (element_size <= 0 || mpi_type == MPI_DATATYPE_NULL || flexio_type<0)
        {
          CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                      "Unsupported variable type %d", vtype);
          continue;
        }

        /* get the pGExtras pointer as a shortcut */
        extras = ((pGA ***) pughGH->variables)[vindex][timelevel]->extras;
        data = CCTK_VarDataPtrI (GH, timelevel, vindex);

        /* get the dimension of the variable */
        dim = CCTK_GroupDimFromVarI (vindex);

        chunkorigin = malloc (2*dim * sizeof (int));
        chunkdims = chunkorigin + dim;

        /* read my own data directly into data,
           read others data into buffer and communicate it */
        if (! file->unchunked || gtype == CCTK_SCALAR)
        {
          FLEXIO_ERROR (IOread (file->fid, data));
        }
        else
        {
          if (extras->rnpoints[file->ioproc] > 0)
          {
            for (i = 0; i < dim; i++)
            {
              chunkdims[i] = extras->rnsize[file->ioproc][i];
              chunkorigin[i] = extras->lb[file->ioproc][i];
            }

            FLEXIO_ERROR (IOreadChunk (file->fid, chunkdims, chunkorigin,data));
          }
        }

        /* read data for non-IO processors */
        if (gtype == CCTK_SCALAR)
        {
          npoints = 1;
          buffer = data;
        }
        else
        {
          /* allocate memory for the biggest chunk */
          npoints = extras->rnpoints[file->ioproc + 1];
          for (proc = 2; proc < file->ioproc_every; proc++)
          {
            if (npoints < extras->rnpoints[file->ioproc + proc])
            {
              npoints = extras->rnpoints[file->ioproc + proc];
            }
          }
          buffer = npoints > 0 ? malloc (npoints * element_size) : NULL;
        }

        for (proc = file->ioproc + 1;
             proc < file->ioproc + file->ioproc_every && proc < nprocs;
             proc++)
        {
          if (gtype != CCTK_SCALAR)
          {
            npoints = extras->rnpoints[proc];

            if (! file->unchunked)
            {
              /* Also increment dataset counter here !!! */
              currentDataset++;

              if (GetChunkAttributes (file->fid, vindex) < 0)
              {
                CCTK_VWarn (1, __LINE__, __FILE__, CCTK_THORNSTRING,
                            "Ignoring chunk in dataset %d", currentDataset+1);
                continue;
              }

              FLEXIO_ERROR (IOread (file->fid, buffer));
            }
            else if (npoints > 0)
            {
              for (i = 0; i < dim; i++)
              {
                chunkdims[i] = extras->rnsize[proc][i];
                chunkorigin[i] = extras->lb[proc][i];
              }

              FLEXIO_ERROR (IOreadChunk (file->fid, chunkdims, chunkorigin,
                                         buffer));
            }
          }

          /* and finally send the index and the data */
          info[0] = vindex; info[1] = timelevel; info[2] = npoints;
          CACTUS_MPI_ERROR (MPI_Send (info, 3, PUGH_MPI_INT, proc,
                                      STARTUPBASE, pughGH->PUGH_COMM_WORLD));
          if (npoints > 0)
          {
            CACTUS_MPI_ERROR (MPI_Send (buffer, npoints, mpi_type, proc,
                                        STARTUPBASE, pughGH->PUGH_COMM_WORLD));
          }
        }

        /* free allocated chunk */
        if (buffer != data)
        {
          free (buffer);
        }

        free (chunkorigin);

      } /* reading data for file->ioproc_every processors */
#endif

    } /* end of loop over all datasets */

#ifdef CCTK_MPI
    /* finally an invalid variable index is communicated
       to indicate completion to the non-I/O processors */
    info[0] = -1;
    for (proc = file->ioproc + 1;
         proc < file->ioproc + file->ioproc_every && proc < nprocs;
         proc++)
    {
      CACTUS_MPI_ERROR (MPI_Send (info, 3, PUGH_MPI_INT, proc,
                                  STARTUPBASE, pughGH->PUGH_COMM_WORLD));
    }
#endif

  }
  else
  {
    /* and here the code for non-IO processors: */
#ifdef CCTK_MPI
    /* They don't know how many datasets there are, because the IO processors
       could skip some on the fly during their consistency checks.
       The IO Processor sends the index of the variable to be processed next.
       So, all non-IO processors execute a loop where the termination condition
       is when an invalid index was received.
    */
    while (1)
    {
      /* receive the next variable index from the IO processor */
      CACTUS_MPI_ERROR (MPI_Recv (info, 3, PUGH_MPI_INT, file->ioproc,
                                  STARTUPBASE, pughGH->PUGH_COMM_WORLD, &ms));
      vindex = info[0]; timelevel = info[1]; npoints = info[2];

      /* check for termination condition */
      if (vindex < 0)
      {
        break;
      }

      /* receive following data from my IO processor */
      if (npoints > 0)
      {
        mpi_type = PUGH_MPIDataType (pughGH, CCTK_VarTypeI (vindex));
        CACTUS_MPI_ERROR (MPI_Recv (CCTK_VarDataPtrI (GH, timelevel, vindex),
                                    npoints, mpi_type, file->ioproc,
                                    STARTUPBASE, pughGH->PUGH_COMM_WORLD, &ms));
      }
    }
#endif
  }

  return (0);
}


/********************************************************************
 ********************    Internal Routines   ************************
 ********************************************************************/
/* local routine getDatasetAttributes() reads in the next dataset's attributes
   and verifies them:

  * checks if there is a variable with the name given by the name attribute
  * verifies that this variable still belongs to the same group
  * checks the group data info:
    - group type
    - variable type
    - ntimelevels
    - iteration number
    - sizes (rank, dimensions) according to chunking mode

 If there is a mismatch a warning (warning level 2) is printed and value of -1
 is returned to indicate that this dataset should be ignored.
 If successful, the global variable index, the group type and the timelevel
 to restore are stored in {*index, *grouptype, *timelevel}, and 0 is returned.
*/

static int GetCommonAttributes (cGH *GH, IOFile fid, int unchunked, int *vindex,
                                int *grouptype, int *timelevel, int *iteration,
                                int has_version)
{
  int i, flag, atype, vartype_stored, rank_stored, groupindex, result;
  Long asize;
  cGroup group_static_data;
  cGroupDynamicData group_dynamic_data;
  CCTK_INT4 grouptype_stored, numtimelevels_stored, timelevel_stored,
            iteration_stored;
  char *groupname, *msg, *oldmsg;
  const int *dims;
  int dims_stored[MAXDIM];
  char fullname[512], groupname_stored[512];


  /* read the next dataset's info from the file */
  result = IOreadInfo (fid, &vartype_stored, &rank_stored, dims_stored, MAXDIM);
  FLEXIO_ERROR (result);
  if (result == 0)
  {
    CCTK_WARN (1, "Can't read dataset info");
    return (-1);
  }

  /* retrieve the name attribute */
  i = IOreadAttributeInfo (fid, "name", &atype, &asize);
  if (i < 0 || atype != CHAR || asize >= (int) sizeof (fullname))
  {
    CCTK_WARN (2, "Can't read name attribute");
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, fullname));

  /* check if there is a matching variable */
  *vindex = CCTK_VarIndex (fullname);
  if (*vindex < 0)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "No matching variable found for '%s'", fullname);
    return (-1);
  }

  /* read and verify the group name */
  i = IOreadAttributeInfo (fid, "groupname", &atype, &asize);
  if (i < 0 || atype != CHAR ||
      (unsigned int) asize >= sizeof (groupname_stored))
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read groupname attribute of '%s'", fullname);
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, groupname_stored));
  groupname = CCTK_GroupNameFromVarI (*vindex);
  if (! CCTK_Equals (groupname_stored, groupname))
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Groupnames don't match for '%s'", fullname);
    return (-1);
  }
  free (groupname);

  /* read the group type */
  i = IOreadAttributeInfo (fid, "grouptype", &atype, &asize);
  if (i < 0 || atype != FLEXIO_INT4 || asize != 1)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read grouptype attribute for '%s'", fullname);
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, &grouptype_stored));
  /* be backwards compatible */
  switch (grouptype_stored)
  {
  case 1: grouptype_stored = CCTK_SCALAR; break;
  case 2: grouptype_stored = CCTK_GF; break;
  case 3: grouptype_stored = CCTK_ARRAY; break;
  }

  /* read the iteration number */
  i = IOreadAttributeInfo (fid, "iteration", &atype, &asize);
  if (i < 0 || atype != FLEXIO_INT4 || asize != 1)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read iteration attribute for '%s'", fullname);
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, &iteration_stored));
  *iteration = iteration_stored;

  /* read the number of timelevels */
  i = IOreadAttributeInfo (fid, "ntimelevels", &atype, &asize);
  if (i < 0 || atype != FLEXIO_INT4 || asize != 1)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read ntimelevels attribute for '%s'", fullname);
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, &numtimelevels_stored));

  /* read the timelevel to restore */
  i = IOreadAttributeInfo (fid, "timelevel", &atype, &asize);
  if (i < 0 || atype != FLEXIO_INT4 || asize != 1)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read timelevel attribute for '%s'", fullname);
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, &timelevel_stored));
  *timelevel = (int) timelevel_stored;

  /* verify group type, variable type, dims, sizes and ntimelevels */
  groupindex = CCTK_GroupIndex (groupname_stored);
  if (CCTK_GroupData (groupindex, &group_static_data) != 0)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Could not get group info for '%s'", fullname);
    return (-1);
  }
  if (group_static_data.grouptype != grouptype_stored)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Group types don't match for '%s'", fullname);
    return (-1);
  }
  if (group_static_data.numtimelevels != numtimelevels_stored)
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Number of timelevels don't match for '%s'", fullname);
    return (-1);
  }
  /* increment the timelevel for data from old checkpoint files */
  if (! has_version && numtimelevels_stored > 1)
  {
    (*timelevel)++;
  }
  /* The CCTK variable type defines do not correlate with the IEEEIO defines
     so compare them explicitely here. */
  if ((vartype_stored == FLEXIO_REAL &&
       group_static_data.vartype == CCTK_VARIABLE_REAL) ||
      (vartype_stored == FLEXIO_INT  &&
       group_static_data.vartype == CCTK_VARIABLE_INT) ||
      (vartype_stored == FLEXIO_BYTE &&
       group_static_data.vartype == CCTK_VARIABLE_BYTE) ||
#if 0
/* FIXME: Don't know how to support COMPLEX type too !! */
      (vartype_stored == FLEXIO_REAL &&
       group_static_data.vartype == CCTK_VARIABLE_COMPLEX))
#else
       0)
  {
#endif
    /* everything is okay */
  }
  else
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Variable types don't match for '%s'", fullname);
    return (-1);
  }

  /* verify the dims and sizes */
  if (group_static_data.grouptype == CCTK_SCALAR)
  {
    rank_stored = 0;
  }
  flag = group_static_data.dim != rank_stored;
  if (group_static_data.grouptype == CCTK_SCALAR)
  {
    flag |= dims_stored[0] != 1;
  }
  else
  {
    if (CCTK_GroupDynamicData (GH, groupindex, &group_dynamic_data) != 0)
    {
      CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "Cannot get dynamic group data for '%s'", fullname);
      return (-1);
    }

    dims = unchunked ? group_dynamic_data.gsh : group_dynamic_data.lsh;
    for (i = 0; i < group_static_data.dim; i++)
    {
      flag |= dims[i] != dims_stored[i];
    }
  }
  if (flag)
  {
    if (group_static_data.dim != rank_stored)
    {
      CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                  "Variable dimensions don't match for '%s', got %d, expected "
                  "%d", fullname, rank_stored, group_static_data.dim);
    }
    else
    {
      msg = NULL;
      Util_asprintf (&msg, "Variable sizes don't match for '%s', got (%d",
                     fullname, dims_stored[0]);
      for (i = 1; i < group_static_data.dim; i++)
      {
        oldmsg = msg;
        Util_asprintf (&msg, "%s, %d", msg, dims_stored[i]);
        free (oldmsg);
      }
      dims = unchunked ? group_dynamic_data.gsh : group_dynamic_data.lsh;
      oldmsg = msg;
      Util_asprintf (&msg, "%s), expected (%d", msg,
                     dims[group_static_data.dim - 1]);
      free (oldmsg);
      for (i = 1; i < group_static_data.dim; i++)
      {
        oldmsg = msg;
        Util_asprintf (&msg, "%s, %d", msg, dims[group_static_data.dim-i-1]);
        free (oldmsg);
      }
      oldmsg = msg;
      Util_asprintf (&msg, "%s)", msg);
      free (oldmsg);
      CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING, msg);
      free (msg);
    }

    return (-1);
  }

  if (! CCTK_QueryGroupStorageI (GH, CCTK_GroupIndexFromVarI (*vindex)))
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "Can't read into '%s': no storage assigned", fullname);
    return (-1);
  }

  *grouptype = group_static_data.grouptype;

  return (0);
}


/* local routine GetChunkAttributes() reads in the info of the next dataset
   that should be a chunk.
   It verifies via the name attribute that this chunk belongs to the
   current variable given by its index. */
#ifdef CCTK_MPI
static int GetChunkAttributes (IOFile fid, int vindex)
{
  int i, atype, vtype_stored, rank_stored;
  Long asize;
  int dims_stored[MAXDIM];
  char fullname[512];


  /* read the next dataset's info from the file */
  if (! IOreadInfo (fid, &vtype_stored, &rank_stored, dims_stored, MAXDIM))
  {
    CCTK_WARN (1, "Can't read dataset info");
    return (-1);
  }

  /* retrieve the name attribute */
  i = IOreadAttributeInfo (fid, "name", &atype, &asize);
  if (i < 0 || atype != CHAR || asize >= (int) sizeof (fullname))
  {
    CCTK_WARN (2, "Can't read name attribute");
    return (-1);
  }
  FLEXIO_ERROR (IOreadAttribute (fid, i, fullname));

  /* check if there is a matching variable */
  if (vindex != CCTK_VarIndex (fullname))
  {
    CCTK_VWarn (2, __LINE__, __FILE__, CCTK_THORNSTRING,
                "No matching variable found for '%s'", fullname);
    return (-1);
  }

  return (0);
}
#endif