xref: /petsc/src/dm/impls/plex/cgns/plexcgns2.c (revision 57d508425293f0bb93f59574d14951d8faac9af8)
1 #define PETSCDM_DLL
2 #include <petsc/private/dmpleximpl.h> /*I   "petscdmplex.h"   I*/
3 #include <petsc/private/viewercgnsimpl.h>
4 
5 #include <pcgnslib.h>
6 #include <cgns_io.h>
7 
8 #if !defined(CGNS_ENUMT)
9   #define CGNS_ENUMT(a) a
10 #endif
11 #if !defined(CGNS_ENUMV)
12   #define CGNS_ENUMV(a) a
13 #endif
14 // Permute plex closure ordering to CGNS
15 static PetscErrorCode DMPlexCGNSGetPermutation_Internal(DMPolytopeType cell_type, PetscInt closure_size, CGNS_ENUMT(ElementType_t) * element_type, const int **perm)
16 {
17   CGNS_ENUMT(ElementType_t) element_type_tmp;
18 
19   // https://cgns.github.io/CGNS_docs_current/sids/conv.html#unstructgrid
20   static const int bar_2[2]   = {0, 1};
21   static const int bar_3[3]   = {1, 2, 0};
22   static const int bar_4[4]   = {2, 3, 0, 1};
23   static const int bar_5[5]   = {3, 4, 0, 1, 2};
24   static const int tri_3[3]   = {0, 1, 2};
25   static const int tri_6[6]   = {3, 4, 5, 0, 1, 2};
26   static const int tri_10[10] = {7, 8, 9, 1, 2, 3, 4, 5, 6, 0};
27   static const int quad_4[4]  = {0, 1, 2, 3};
28   static const int quad_9[9]  = {
29     5, 6, 7, 8, // vertices
30     1, 2, 3, 4, // edges
31     0,          // center
32   };
33   static const int quad_16[] = {
34     12, 13, 14, 15,               // vertices
35     4,  5,  6,  7,  8, 9, 10, 11, // edges
36     0,  1,  3,  2,                // centers
37   };
38   static const int quad_25[] = {
39     21, 22, 23, 24,                                 // vertices
40     9,  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, // edges
41     0,  1,  2,  5,  8,  7,  6,  3,  4,              // centers
42   };
43   static const int tetra_4[4]   = {0, 2, 1, 3};
44   static const int tetra_10[10] = {6, 8, 7, 9, 2, 1, 0, 3, 5, 4};
45   static const int tetra_20[20] = {
46     16, 18, 17, 19,         // vertices
47     9,  8,  7,  6,  5,  4,  // bottom edges
48     10, 11, 14, 15, 13, 12, // side edges
49     0,  2,  3,  1,          // faces
50   };
51   static const int hexa_8[8]   = {0, 3, 2, 1, 4, 5, 6, 7};
52   static const int hexa_27[27] = {
53     19, 22, 21, 20, 23, 24, 25, 26, // vertices
54     10, 9,  8,  7,                  // bottom edges
55     16, 15, 18, 17,                 // mid edges
56     11, 12, 13, 14,                 // top edges
57     1,  3,  5,  4,  6,  2,          // faces
58     0,                              // center
59   };
60   static const int hexa_64[64] = {
61     // debug with $PETSC_ARCH/tests/dm/impls/plex/tests/ex49 -dm_plex_simplex 0 -dm_plex_dim 3 -dm_plex_box_faces 1,1,1 -dm_coord_petscspace_degree 3
62     56, 59, 58, 57, 60, 61, 62, 63, // vertices
63     39, 38, 37, 36, 35, 34, 33, 32, // bottom edges
64     51, 50, 48, 49, 52, 53, 55, 54, // mid edges; Paraview needs edge 21-22 swapped with 23-24
65     40, 41, 42, 43, 44, 45, 46, 47, // top edges
66     8,  10, 11, 9,                  // z-minus face
67     16, 17, 19, 18,                 // y-minus face
68     24, 25, 27, 26,                 // x-plus face
69     20, 21, 23, 22,                 // y-plus face
70     30, 28, 29, 31,                 // x-minus face
71     12, 13, 15, 14,                 // z-plus face
72     0,  1,  3,  2,  4,  5,  7,  6,  // center
73   };
74 
75   PetscFunctionBegin;
76   element_type_tmp = CGNS_ENUMV(ElementTypeNull);
77   *perm            = NULL;
78   switch (cell_type) {
79   case DM_POLYTOPE_SEGMENT:
80     switch (closure_size) {
81     case 2:
82       element_type_tmp = CGNS_ENUMV(BAR_2);
83       *perm            = bar_2;
84     case 3:
85       element_type_tmp = CGNS_ENUMV(BAR_3);
86       *perm            = bar_3;
87     case 4:
88       element_type_tmp = CGNS_ENUMV(BAR_4);
89       *perm            = bar_4;
90       break;
91     case 5:
92       element_type_tmp = CGNS_ENUMV(BAR_5);
93       *perm            = bar_5;
94       break;
95     default:
96       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
97     }
98     break;
99   case DM_POLYTOPE_TRIANGLE:
100     switch (closure_size) {
101     case 3:
102       element_type_tmp = CGNS_ENUMV(TRI_3);
103       *perm            = tri_3;
104       break;
105     case 6:
106       element_type_tmp = CGNS_ENUMV(TRI_6);
107       *perm            = tri_6;
108       break;
109     case 10:
110       element_type_tmp = CGNS_ENUMV(TRI_10);
111       *perm            = tri_10;
112       break;
113     default:
114       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
115     }
116     break;
117   case DM_POLYTOPE_QUADRILATERAL:
118     switch (closure_size) {
119     case 4:
120       element_type_tmp = CGNS_ENUMV(QUAD_4);
121       *perm            = quad_4;
122       break;
123     case 9:
124       element_type_tmp = CGNS_ENUMV(QUAD_9);
125       *perm            = quad_9;
126       break;
127     case 16:
128       element_type_tmp = CGNS_ENUMV(QUAD_16);
129       *perm            = quad_16;
130       break;
131     case 25:
132       element_type_tmp = CGNS_ENUMV(QUAD_25);
133       *perm            = quad_25;
134       break;
135     default:
136       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
137     }
138     break;
139   case DM_POLYTOPE_TETRAHEDRON:
140     switch (closure_size) {
141     case 4:
142       element_type_tmp = CGNS_ENUMV(TETRA_4);
143       *perm            = tetra_4;
144       break;
145     case 10:
146       element_type_tmp = CGNS_ENUMV(TETRA_10);
147       *perm            = tetra_10;
148       break;
149     case 20:
150       element_type_tmp = CGNS_ENUMV(TETRA_20);
151       *perm            = tetra_20;
152       break;
153     default:
154       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
155     }
156     break;
157   case DM_POLYTOPE_HEXAHEDRON:
158     switch (closure_size) {
159     case 8:
160       element_type_tmp = CGNS_ENUMV(HEXA_8);
161       *perm            = hexa_8;
162       break;
163     case 27:
164       element_type_tmp = CGNS_ENUMV(HEXA_27);
165       *perm            = hexa_27;
166       break;
167     case 64:
168       element_type_tmp = CGNS_ENUMV(HEXA_64);
169       *perm            = hexa_64;
170       break;
171     default:
172       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
173     }
174     break;
175   default:
176     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Cell type %s with closure size %" PetscInt_FMT, DMPolytopeTypes[cell_type], closure_size);
177   }
178   if (element_type) *element_type = element_type_tmp;
179   PetscFunctionReturn(PETSC_SUCCESS);
180 }
181 
182 /*
183   Input Parameters:
184 + cellType  - The CGNS-defined element type
185 
186   Output Parameters:
187 + dmcelltype  - The equivalent DMPolytopeType for the cellType
188 . numCorners - Number of corners of the polytope
189 - dim - The topological dimension of the polytope
190 
191 CGNS elements defined in: https://cgns.github.io/CGNS_docs_current/sids/conv.html#unstructgrid
192 */
193 static inline PetscErrorCode CGNSElementTypeGetTopologyInfo(CGNS_ENUMT(ElementType_t) cellType, DMPolytopeType *dmcelltype, PetscInt *numCorners, PetscInt *dim)
194 {
195   DMPolytopeType _dmcelltype;
196 
197   PetscFunctionBeginUser;
198   switch (cellType) {
199   case CGNS_ENUMV(BAR_2):
200   case CGNS_ENUMV(BAR_3):
201   case CGNS_ENUMV(BAR_4):
202   case CGNS_ENUMV(BAR_5):
203     _dmcelltype = DM_POLYTOPE_SEGMENT;
204     break;
205   case CGNS_ENUMV(TRI_3):
206   case CGNS_ENUMV(TRI_6):
207   case CGNS_ENUMV(TRI_9):
208   case CGNS_ENUMV(TRI_10):
209   case CGNS_ENUMV(TRI_12):
210   case CGNS_ENUMV(TRI_15):
211     _dmcelltype = DM_POLYTOPE_TRIANGLE;
212     break;
213   case CGNS_ENUMV(QUAD_4):
214   case CGNS_ENUMV(QUAD_8):
215   case CGNS_ENUMV(QUAD_9):
216   case CGNS_ENUMV(QUAD_12):
217   case CGNS_ENUMV(QUAD_16):
218   case CGNS_ENUMV(QUAD_P4_16):
219   case CGNS_ENUMV(QUAD_25):
220     _dmcelltype = DM_POLYTOPE_QUADRILATERAL;
221     break;
222   case CGNS_ENUMV(TETRA_4):
223   case CGNS_ENUMV(TETRA_10):
224   case CGNS_ENUMV(TETRA_16):
225   case CGNS_ENUMV(TETRA_20):
226   case CGNS_ENUMV(TETRA_22):
227   case CGNS_ENUMV(TETRA_34):
228   case CGNS_ENUMV(TETRA_35):
229     _dmcelltype = DM_POLYTOPE_TETRAHEDRON;
230     break;
231   case CGNS_ENUMV(PYRA_5):
232   case CGNS_ENUMV(PYRA_13):
233   case CGNS_ENUMV(PYRA_14):
234   case CGNS_ENUMV(PYRA_21):
235   case CGNS_ENUMV(PYRA_29):
236   case CGNS_ENUMV(PYRA_P4_29):
237   case CGNS_ENUMV(PYRA_30):
238   case CGNS_ENUMV(PYRA_50):
239   case CGNS_ENUMV(PYRA_55):
240     _dmcelltype = DM_POLYTOPE_PYRAMID;
241     break;
242   case CGNS_ENUMV(PENTA_6):
243   case CGNS_ENUMV(PENTA_15):
244   case CGNS_ENUMV(PENTA_18):
245   case CGNS_ENUMV(PENTA_24):
246   case CGNS_ENUMV(PENTA_33):
247   case CGNS_ENUMV(PENTA_38):
248   case CGNS_ENUMV(PENTA_40):
249   case CGNS_ENUMV(PENTA_66):
250   case CGNS_ENUMV(PENTA_75):
251     _dmcelltype = DM_POLYTOPE_TRI_PRISM;
252     break;
253   case CGNS_ENUMV(HEXA_8):
254   case CGNS_ENUMV(HEXA_20):
255   case CGNS_ENUMV(HEXA_27):
256   case CGNS_ENUMV(HEXA_32):
257   case CGNS_ENUMV(HEXA_44):
258   case CGNS_ENUMV(HEXA_56):
259   case CGNS_ENUMV(HEXA_64):
260   case CGNS_ENUMV(HEXA_98):
261   case CGNS_ENUMV(HEXA_125):
262     _dmcelltype = DM_POLYTOPE_HEXAHEDRON;
263     break;
264   case CGNS_ENUMV(MIXED):
265     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid CGNS ElementType_t: MIXED");
266   default:
267     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid CGNS ElementType_t: %d", (int)cellType);
268   }
269 
270   if (dmcelltype) *dmcelltype = _dmcelltype;
271   if (numCorners) *numCorners = DMPolytopeTypeGetNumVertices(_dmcelltype);
272   if (dim) *dim = DMPolytopeTypeGetDim(_dmcelltype);
273   PetscFunctionReturn(PETSC_SUCCESS);
274 }
275 
276 /*
277   Input Parameters:
278 + cellType  - The CGNS-defined cell type
279 
280   Output Parameters:
281 + numClosure - Number of nodes that define the function space on the cell
282 - pOrder - The polynomial order of the cell
283 
284 CGNS elements defined in: https://cgns.github.io/CGNS_docs_current/sids/conv.html#unstructgrid
285 
286 Note: we only support "full" elements, ie. not seredipity elements
287 */
288 static inline PetscErrorCode CGNSElementTypeGetDiscretizationInfo(CGNS_ENUMT(ElementType_t) cellType, PetscInt *numClosure, PetscInt *pOrder)
289 {
290   PetscInt _numClosure, _pOrder;
291 
292   PetscFunctionBeginUser;
293   switch (cellType) {
294   case CGNS_ENUMV(BAR_2):
295     _numClosure = 2;
296     _pOrder     = 1;
297     break;
298   case CGNS_ENUMV(BAR_3):
299     _numClosure = 3;
300     _pOrder     = 2;
301     break;
302   case CGNS_ENUMV(BAR_4):
303     _numClosure = 4;
304     _pOrder     = 3;
305     break;
306   case CGNS_ENUMV(BAR_5):
307     _numClosure = 5;
308     _pOrder     = 4;
309     break;
310   case CGNS_ENUMV(TRI_3):
311     _numClosure = 3;
312     _pOrder     = 1;
313     break;
314   case CGNS_ENUMV(TRI_6):
315     _numClosure = 6;
316     _pOrder     = 2;
317     break;
318   case CGNS_ENUMV(TRI_10):
319     _numClosure = 10;
320     _pOrder     = 3;
321     break;
322   case CGNS_ENUMV(TRI_15):
323     _numClosure = 15;
324     _pOrder     = 4;
325     break;
326   case CGNS_ENUMV(QUAD_4):
327     _numClosure = 4;
328     _pOrder     = 1;
329     break;
330   case CGNS_ENUMV(QUAD_9):
331     _numClosure = 9;
332     _pOrder     = 2;
333     break;
334   case CGNS_ENUMV(QUAD_16):
335     _numClosure = 16;
336     _pOrder     = 3;
337     break;
338   case CGNS_ENUMV(QUAD_25):
339     _numClosure = 25;
340     _pOrder     = 4;
341     break;
342   case CGNS_ENUMV(TETRA_4):
343     _numClosure = 4;
344     _pOrder     = 1;
345     break;
346   case CGNS_ENUMV(TETRA_10):
347     _numClosure = 10;
348     _pOrder     = 2;
349     break;
350   case CGNS_ENUMV(TETRA_20):
351     _numClosure = 20;
352     _pOrder     = 3;
353     break;
354   case CGNS_ENUMV(TETRA_35):
355     _numClosure = 35;
356     _pOrder     = 4;
357     break;
358   case CGNS_ENUMV(PYRA_5):
359     _numClosure = 5;
360     _pOrder     = 1;
361     break;
362   case CGNS_ENUMV(PYRA_14):
363     _numClosure = 14;
364     _pOrder     = 2;
365     break;
366   case CGNS_ENUMV(PYRA_30):
367     _numClosure = 30;
368     _pOrder     = 3;
369     break;
370   case CGNS_ENUMV(PYRA_55):
371     _numClosure = 55;
372     _pOrder     = 4;
373     break;
374   case CGNS_ENUMV(PENTA_6):
375     _numClosure = 6;
376     _pOrder     = 1;
377     break;
378   case CGNS_ENUMV(PENTA_18):
379     _numClosure = 18;
380     _pOrder     = 2;
381     break;
382   case CGNS_ENUMV(PENTA_40):
383     _numClosure = 40;
384     _pOrder     = 3;
385     break;
386   case CGNS_ENUMV(PENTA_75):
387     _numClosure = 75;
388     _pOrder     = 4;
389     break;
390   case CGNS_ENUMV(HEXA_8):
391     _numClosure = 8;
392     _pOrder     = 1;
393     break;
394   case CGNS_ENUMV(HEXA_27):
395     _numClosure = 27;
396     _pOrder     = 2;
397     break;
398   case CGNS_ENUMV(HEXA_64):
399     _numClosure = 64;
400     _pOrder     = 3;
401     break;
402   case CGNS_ENUMV(HEXA_125):
403     _numClosure = 125;
404     _pOrder     = 4;
405     break;
406   case CGNS_ENUMV(MIXED):
407     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid CGNS ElementType_t: MIXED");
408   default:
409     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Unsupported or Invalid cell type %d", (int)cellType);
410   }
411   if (numClosure) *numClosure = _numClosure;
412   if (pOrder) *pOrder = _pOrder;
413   PetscFunctionReturn(PETSC_SUCCESS);
414 }
415 
416 static PetscErrorCode PetscCGNSDataType(PetscDataType pd, CGNS_ENUMT(DataType_t) * cd)
417 {
418   PetscFunctionBegin;
419   switch (pd) {
420   case PETSC_FLOAT:
421     *cd = CGNS_ENUMV(RealSingle);
422     break;
423   case PETSC_DOUBLE:
424     *cd = CGNS_ENUMV(RealDouble);
425     break;
426   case PETSC_COMPLEX:
427     *cd = CGNS_ENUMV(ComplexDouble);
428     break;
429   default:
430     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Data type %s", PetscDataTypes[pd]);
431   }
432   PetscFunctionReturn(PETSC_SUCCESS);
433 }
434 
435 PetscErrorCode DMPlexCreateCGNSFromFile_Internal(MPI_Comm comm, const char filename[], PetscBool interpolate, DM *dm)
436 {
437   int       cgid                = -1;
438   PetscBool use_parallel_viewer = PETSC_FALSE;
439 
440   PetscFunctionBegin;
441   PetscAssertPointer(filename, 2);
442   PetscCall(PetscViewerCGNSRegisterLogEvents_Internal());
443   PetscCall(PetscOptionsGetBool(NULL, NULL, "-dm_plex_cgns_parallel", &use_parallel_viewer, NULL));
444 
445   if (use_parallel_viewer) {
446     PetscCallCGNS(cgp_mpi_comm(comm));
447     PetscCallCGNSOpen(cgp_open(filename, CG_MODE_READ, &cgid), 0, 0);
448     PetscCheck(cgid > 0, PETSC_COMM_SELF, PETSC_ERR_LIB, "cgp_open(\"%s\",...) did not return a valid file ID", filename);
449     PetscCall(DMPlexCreateCGNS(comm, cgid, interpolate, dm));
450     PetscCallCGNSClose(cgp_close(cgid), 0, 0);
451   } else {
452     PetscCallCGNSOpen(cg_open(filename, CG_MODE_READ, &cgid), 0, 0);
453     PetscCheck(cgid > 0, PETSC_COMM_SELF, PETSC_ERR_LIB, "cg_open(\"%s\",...) did not return a valid file ID", filename);
454     PetscCall(DMPlexCreateCGNS(comm, cgid, interpolate, dm));
455     PetscCallCGNSClose(cg_close(cgid), 0, 0);
456   }
457   PetscFunctionReturn(PETSC_SUCCESS);
458 }
459 
460 PetscErrorCode DMPlexCreateCGNS_Internal_Serial(MPI_Comm comm, PetscInt cgid, PetscBool interpolate, DM *dm)
461 {
462   PetscMPIInt  num_proc, rank;
463   DM           cdm;
464   DMLabel      label;
465   PetscSection coordSection;
466   Vec          coordinates;
467   PetscScalar *coords;
468   PetscInt    *cellStart, *vertStart, v;
469   PetscInt     labelIdRange[2], labelId;
470   /* Read from file */
471   char      basename[CGIO_MAX_NAME_LENGTH + 1];
472   char      buffer[CGIO_MAX_NAME_LENGTH + 1];
473   int       dim = 0, physDim = 0, coordDim = 0, numVertices = 0, numCells = 0;
474   int       nzones = 0;
475   const int B      = 1; // Only support single base
476 
477   PetscFunctionBegin;
478   PetscCallMPI(MPI_Comm_rank(comm, &rank));
479   PetscCallMPI(MPI_Comm_size(comm, &num_proc));
480   PetscCall(DMCreate(comm, dm));
481   PetscCall(DMSetType(*dm, DMPLEX));
482 
483   /* Open CGNS II file and read basic information on rank 0, then broadcast to all processors */
484   if (rank == 0) {
485     int nbases, z;
486 
487     PetscCallCGNSRead(cg_nbases(cgid, &nbases), *dm, 0);
488     PetscCheck(nbases <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single base, not %d", nbases);
489     PetscCallCGNSRead(cg_base_read(cgid, B, basename, &dim, &physDim), *dm, 0);
490     PetscCallCGNSRead(cg_nzones(cgid, B, &nzones), *dm, 0);
491     PetscCall(PetscCalloc2(nzones + 1, &cellStart, nzones + 1, &vertStart));
492     for (z = 1; z <= nzones; ++z) {
493       cgsize_t sizes[3]; /* Number of vertices, number of cells, number of boundary vertices */
494 
495       PetscCallCGNSRead(cg_zone_read(cgid, B, z, buffer, sizes), *dm, 0);
496       numVertices += sizes[0];
497       numCells += sizes[1];
498       cellStart[z] += sizes[1] + cellStart[z - 1];
499       vertStart[z] += sizes[0] + vertStart[z - 1];
500     }
501     for (z = 1; z <= nzones; ++z) vertStart[z] += numCells;
502     coordDim = dim;
503   }
504   PetscCallMPI(MPI_Bcast(basename, CGIO_MAX_NAME_LENGTH + 1, MPI_CHAR, 0, comm));
505   PetscCallMPI(MPI_Bcast(&dim, 1, MPI_INT, 0, comm));
506   PetscCallMPI(MPI_Bcast(&coordDim, 1, MPI_INT, 0, comm));
507   PetscCallMPI(MPI_Bcast(&nzones, 1, MPI_INT, 0, comm));
508 
509   PetscCall(PetscObjectSetName((PetscObject)*dm, basename));
510   PetscCall(DMSetDimension(*dm, dim));
511   PetscCall(DMCreateLabel(*dm, "celltype"));
512   PetscCall(DMPlexSetChart(*dm, 0, numCells + numVertices));
513 
514   /* Read zone information */
515   if (rank == 0) {
516     int z, c, c_loc;
517 
518     /* Read the cell set connectivity table and build mesh topology
519        CGNS standard requires that cells in a zone be numbered sequentially and be pairwise disjoint. */
520     /* First set sizes */
521     for (z = 1, c = 0; z <= nzones; ++z) {
522       CGNS_ENUMT(ZoneType_t) zonetype;
523       int nsections;
524       CGNS_ENUMT(ElementType_t) cellType;
525       cgsize_t       start, end;
526       int            nbndry, parentFlag;
527       PetscInt       numCorners, pOrder;
528       DMPolytopeType ctype;
529       const int      S = 1; // Only support single section
530 
531       PetscCallCGNSRead(cg_zone_type(cgid, B, z, &zonetype), *dm, 0);
532       PetscCheck(zonetype != CGNS_ENUMV(Structured), PETSC_COMM_SELF, PETSC_ERR_LIB, "Can only handle Unstructured zones for CGNS");
533       PetscCallCGNSRead(cg_nsections(cgid, B, z, &nsections), *dm, 0);
534       PetscCheck(nsections <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single section, not %d", nsections);
535       PetscCallCGNSRead(cg_section_read(cgid, B, z, S, buffer, &cellType, &start, &end, &nbndry, &parentFlag), *dm, 0);
536       if (cellType == CGNS_ENUMV(MIXED)) {
537         cgsize_t elementDataSize, *elements;
538         PetscInt off;
539 
540         PetscCallCGNSRead(cg_ElementDataSize(cgid, B, z, S, &elementDataSize), *dm, 0);
541         PetscCall(PetscMalloc1(elementDataSize, &elements));
542         PetscCallCGNSReadData(cg_poly_elements_read(cgid, B, z, S, elements, NULL, NULL), *dm, 0);
543         for (c_loc = start, off = 0; c_loc <= end; ++c_loc, ++c) {
544           PetscCall(CGNSElementTypeGetTopologyInfo((CGNS_ENUMT(ElementType_t))elements[off], &ctype, &numCorners, NULL));
545           PetscCall(CGNSElementTypeGetDiscretizationInfo((CGNS_ENUMT(ElementType_t))elements[off], NULL, &pOrder));
546           PetscCheck(pOrder == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Serial CGNS reader only supports first order elements, not %" PetscInt_FMT " order", pOrder);
547           PetscCall(DMPlexSetConeSize(*dm, c, numCorners));
548           PetscCall(DMPlexSetCellType(*dm, c, ctype));
549           off += numCorners + 1;
550         }
551         PetscCall(PetscFree(elements));
552       } else {
553         PetscCall(CGNSElementTypeGetTopologyInfo(cellType, &ctype, &numCorners, NULL));
554         PetscCall(CGNSElementTypeGetDiscretizationInfo(cellType, NULL, &pOrder));
555         PetscCheck(pOrder == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Serial CGNS reader only supports first order elements, not %" PetscInt_FMT " order", pOrder);
556         for (c_loc = start; c_loc <= end; ++c_loc, ++c) {
557           PetscCall(DMPlexSetConeSize(*dm, c, numCorners));
558           PetscCall(DMPlexSetCellType(*dm, c, ctype));
559         }
560       }
561     }
562     for (v = numCells; v < numCells + numVertices; ++v) PetscCall(DMPlexSetCellType(*dm, v, DM_POLYTOPE_POINT));
563   }
564 
565   PetscCall(DMSetUp(*dm));
566 
567   PetscCall(DMCreateLabel(*dm, "zone"));
568   if (rank == 0) {
569     int z, c, c_loc, v_loc;
570 
571     PetscCall(DMGetLabel(*dm, "zone", &label));
572     for (z = 1, c = 0; z <= nzones; ++z) {
573       CGNS_ENUMT(ElementType_t) cellType;
574       cgsize_t  elementDataSize, *elements, start, end;
575       int       nbndry, parentFlag;
576       PetscInt *cone, numc, numCorners, maxCorners = 27, pOrder;
577       const int S = 1; // Only support single section
578 
579       PetscCallCGNSRead(cg_section_read(cgid, B, z, S, buffer, &cellType, &start, &end, &nbndry, &parentFlag), *dm, 0);
580       numc = end - start;
581       PetscCallCGNSRead(cg_ElementDataSize(cgid, B, z, S, &elementDataSize), *dm, 0);
582       PetscCall(PetscMalloc2(elementDataSize, &elements, maxCorners, &cone));
583       PetscCallCGNSReadData(cg_poly_elements_read(cgid, B, z, S, elements, NULL, NULL), *dm, 0);
584       if (cellType == CGNS_ENUMV(MIXED)) {
585         /* CGNS uses Fortran-based indexing, DMPlex uses C-style and numbers cell first then vertices. */
586         for (c_loc = 0, v = 0; c_loc <= numc; ++c_loc, ++c) {
587           PetscCall(CGNSElementTypeGetTopologyInfo((CGNS_ENUMT(ElementType_t))elements[v], NULL, &numCorners, NULL));
588           PetscCall(CGNSElementTypeGetDiscretizationInfo((CGNS_ENUMT(ElementType_t))elements[v], NULL, &pOrder));
589           PetscCheck(pOrder == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Serial CGNS reader only supports first order elements, not %" PetscInt_FMT " order", pOrder);
590           ++v;
591           for (v_loc = 0; v_loc < numCorners; ++v_loc, ++v) cone[v_loc] = elements[v] + numCells - 1;
592           PetscCall(DMPlexReorderCell(*dm, c, cone));
593           PetscCall(DMPlexSetCone(*dm, c, cone));
594           PetscCall(DMLabelSetValue(label, c, z));
595         }
596       } else {
597         PetscCall(CGNSElementTypeGetTopologyInfo(cellType, NULL, &numCorners, NULL));
598         PetscCall(CGNSElementTypeGetDiscretizationInfo(cellType, NULL, &pOrder));
599         PetscCheck(pOrder == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Serial CGNS reader only supports first order elements, not %" PetscInt_FMT " order", pOrder);
600         /* CGNS uses Fortran-based indexing, DMPlex uses C-style and numbers cell first then vertices. */
601         for (c_loc = 0, v = 0; c_loc <= numc; ++c_loc, ++c) {
602           for (v_loc = 0; v_loc < numCorners; ++v_loc, ++v) cone[v_loc] = elements[v] + numCells - 1;
603           PetscCall(DMPlexReorderCell(*dm, c, cone));
604           PetscCall(DMPlexSetCone(*dm, c, cone));
605           PetscCall(DMLabelSetValue(label, c, z));
606         }
607       }
608       PetscCall(PetscFree2(elements, cone));
609     }
610   }
611 
612   PetscCall(DMPlexSymmetrize(*dm));
613   PetscCall(DMPlexStratify(*dm));
614   if (interpolate) PetscCall(DMPlexInterpolateInPlace_Internal(*dm));
615 
616   /* Read coordinates */
617   PetscCall(DMSetCoordinateDim(*dm, coordDim));
618   PetscCall(DMGetCoordinateDM(*dm, &cdm));
619   PetscCall(DMGetLocalSection(cdm, &coordSection));
620   PetscCall(PetscSectionSetNumFields(coordSection, 1));
621   PetscCall(PetscSectionSetFieldComponents(coordSection, 0, coordDim));
622   PetscCall(PetscSectionSetChart(coordSection, numCells, numCells + numVertices));
623   for (v = numCells; v < numCells + numVertices; ++v) {
624     PetscCall(PetscSectionSetDof(coordSection, v, dim));
625     PetscCall(PetscSectionSetFieldDof(coordSection, v, 0, coordDim));
626   }
627   PetscCall(PetscSectionSetUp(coordSection));
628 
629   PetscCall(DMCreateLocalVector(cdm, &coordinates));
630   PetscCall(VecGetArray(coordinates, &coords));
631   if (rank == 0) {
632     PetscInt off = 0;
633     float   *x[3];
634     int      z, d;
635 
636     PetscCall(PetscMalloc3(numVertices, &x[0], numVertices, &x[1], numVertices, &x[2]));
637     for (z = 1; z <= nzones; ++z) {
638       CGNS_ENUMT(DataType_t) datatype;
639       cgsize_t sizes[3]; /* Number of vertices, number of cells, number of boundary vertices */
640       cgsize_t range_min[3] = {1, 1, 1};
641       cgsize_t range_max[3] = {1, 1, 1};
642       int      ngrids, ncoords;
643 
644       PetscCallCGNSRead(cg_zone_read(cgid, B, z, buffer, sizes), *dm, 0);
645       range_max[0] = sizes[0];
646       PetscCallCGNSRead(cg_ngrids(cgid, B, z, &ngrids), *dm, 0);
647       PetscCheck(ngrids <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single grid, not %d", ngrids);
648       PetscCallCGNSRead(cg_ncoords(cgid, B, z, &ncoords), *dm, 0);
649       PetscCheck(ncoords == coordDim, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a coordinate array for each dimension, not %d", ncoords);
650       for (d = 0; d < coordDim; ++d) {
651         PetscCallCGNSRead(cg_coord_info(cgid, B, z, 1 + d, &datatype, buffer), *dm, 0);
652         PetscCallCGNSReadData(cg_coord_read(cgid, B, z, buffer, CGNS_ENUMV(RealSingle), range_min, range_max, x[d]), *dm, 0);
653       }
654       if (coordDim >= 1) {
655         for (v = 0; v < sizes[0]; ++v) coords[(v + off) * coordDim + 0] = x[0][v];
656       }
657       if (coordDim >= 2) {
658         for (v = 0; v < sizes[0]; ++v) coords[(v + off) * coordDim + 1] = x[1][v];
659       }
660       if (coordDim >= 3) {
661         for (v = 0; v < sizes[0]; ++v) coords[(v + off) * coordDim + 2] = x[2][v];
662       }
663       off += sizes[0];
664     }
665     PetscCall(PetscFree3(x[0], x[1], x[2]));
666   }
667   PetscCall(VecRestoreArray(coordinates, &coords));
668 
669   PetscCall(PetscObjectSetName((PetscObject)coordinates, "coordinates"));
670   PetscCall(VecSetBlockSize(coordinates, coordDim));
671   PetscCall(DMSetCoordinatesLocal(*dm, coordinates));
672   PetscCall(VecDestroy(&coordinates));
673 
674   /* Read boundary conditions */
675   PetscCall(DMGetNumLabels(*dm, &labelIdRange[0]));
676   if (rank == 0) {
677     CGNS_ENUMT(BCType_t) bctype;
678     CGNS_ENUMT(DataType_t) datatype;
679     CGNS_ENUMT(PointSetType_t) pointtype;
680     cgsize_t  *points;
681     PetscReal *normals;
682     int        normal[3];
683     char      *bcname = buffer;
684     cgsize_t   npoints, nnormals;
685     int        z, nbc, bc, c, ndatasets;
686 
687     for (z = 1; z <= nzones; ++z) {
688       PetscCallCGNSRead(cg_nbocos(cgid, B, z, &nbc), *dm, 0);
689       for (bc = 1; bc <= nbc; ++bc) {
690         PetscCallCGNSRead(cg_boco_info(cgid, B, z, bc, bcname, &bctype, &pointtype, &npoints, normal, &nnormals, &datatype, &ndatasets), *dm, 0);
691         PetscCall(DMCreateLabel(*dm, bcname));
692         PetscCall(DMGetLabel(*dm, bcname, &label));
693         PetscCall(PetscMalloc2(npoints, &points, nnormals, &normals));
694         PetscCallCGNSReadData(cg_boco_read(cgid, B, z, bc, points, (void *)normals), *dm, 0);
695         if (pointtype == CGNS_ENUMV(ElementRange)) {
696           // Range of cells: assuming half-open interval
697           for (c = points[0]; c < points[1]; ++c) PetscCall(DMLabelSetValue(label, c - cellStart[z - 1], 1));
698         } else if (pointtype == CGNS_ENUMV(ElementList)) {
699           // List of cells
700           for (c = 0; c < npoints; ++c) PetscCall(DMLabelSetValue(label, points[c] - cellStart[z - 1], 1));
701         } else if (pointtype == CGNS_ENUMV(PointRange)) {
702           CGNS_ENUMT(GridLocation_t) gridloc;
703 
704           // List of points:
705           PetscCallCGNS(cg_goto(cgid, 1, "Zone_t", z, "BC_t", bc, "end"));
706           PetscCallCGNSRead(cg_gridlocation_read(&gridloc), *dm, 0);
707           // Range of points: assuming half-open interval
708           for (c = points[0]; c < points[1]; ++c) {
709             if (gridloc == CGNS_ENUMV(Vertex)) PetscCall(DMLabelSetValue(label, c - vertStart[z - 1], 1));
710             else PetscCall(DMLabelSetValue(label, c - cellStart[z - 1], 1));
711           }
712         } else if (pointtype == CGNS_ENUMV(PointList)) {
713           CGNS_ENUMT(GridLocation_t) gridloc;
714 
715           // List of points:
716           PetscCallCGNS(cg_goto(cgid, 1, "Zone_t", z, "BC_t", bc, "end"));
717           PetscCallCGNSRead(cg_gridlocation_read(&gridloc), *dm, 0);
718           for (c = 0; c < npoints; ++c) {
719             if (gridloc == CGNS_ENUMV(Vertex)) PetscCall(DMLabelSetValue(label, points[c] - vertStart[z - 1], 1));
720             else PetscCall(DMLabelSetValue(label, points[c] - cellStart[z - 1], 1));
721           }
722         } else SETERRQ(comm, PETSC_ERR_SUP, "Unsupported point set type %d", (int)pointtype);
723         PetscCall(PetscFree2(points, normals));
724       }
725     }
726     PetscCall(PetscFree2(cellStart, vertStart));
727   }
728   PetscCall(DMGetNumLabels(*dm, &labelIdRange[1]));
729   PetscCallMPI(MPI_Bcast(labelIdRange, 2, MPIU_INT, 0, comm));
730 
731   /* Create BC labels at all processes */
732   for (labelId = labelIdRange[0]; labelId < labelIdRange[1]; ++labelId) {
733     char       *labelName = buffer;
734     size_t      len       = sizeof(buffer);
735     const char *locName;
736 
737     if (rank == 0) {
738       PetscCall(DMGetLabelByNum(*dm, labelId, &label));
739       PetscCall(PetscObjectGetName((PetscObject)label, &locName));
740       PetscCall(PetscStrncpy(labelName, locName, len));
741     }
742     PetscCallMPI(MPI_Bcast(labelName, (PetscMPIInt)len, MPIU_INT, 0, comm));
743     PetscCallMPI(DMCreateLabel(*dm, labelName));
744   }
745   PetscFunctionReturn(PETSC_SUCCESS);
746 }
747 
748 PetscErrorCode DMPlexCreateCGNS_Internal_Parallel(MPI_Comm comm, PetscInt cgid, PetscBool interpolate, DM *dm)
749 {
750   PetscMPIInt num_proc, rank;
751   /* Read from file */
752   char     basename[CGIO_MAX_NAME_LENGTH + 1];
753   char     buffer[CGIO_MAX_NAME_LENGTH + 1];
754   int      dim = 0, physDim = 0, coordDim = 0;
755   PetscInt NVertices = 0, NCells = 0;
756   int      nzones = 0, nbases;
757   int      z      = 1; // Only supports single zone files
758   int      B      = 1; // Only supports single base
759 
760   PetscFunctionBegin;
761   PetscCallMPI(MPI_Comm_rank(comm, &rank));
762   PetscCallMPI(MPI_Comm_size(comm, &num_proc));
763   PetscCall(DMCreate(comm, dm));
764   PetscCall(DMSetType(*dm, DMPLEX));
765 
766   PetscCallCGNSRead(cg_nbases(cgid, &nbases), *dm, 0);
767   PetscCheck(nbases <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single base, not %d", nbases);
768   //  From the CGNS web page                 cell_dim  phys_dim (embedding space in PETSc) CGNS defines as length of spatial vectors/components)
769   PetscCallCGNSRead(cg_base_read(cgid, B, basename, &dim, &physDim), *dm, 0);
770   PetscCallCGNSRead(cg_nzones(cgid, B, &nzones), *dm, 0);
771   PetscCheck(nzones == 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "Parallel reader limited to one zone, not %d", nzones);
772   {
773     cgsize_t sizes[3]; /* Number of vertices, number of cells, number of boundary vertices */
774 
775     PetscCallCGNSRead(cg_zone_read(cgid, B, z, buffer, sizes), *dm, 0);
776     NVertices = sizes[0];
777     NCells    = sizes[1];
778   }
779 
780   PetscCall(PetscObjectSetName((PetscObject)*dm, basename));
781   PetscCall(DMSetDimension(*dm, dim));
782   coordDim = dim;
783 
784   // This is going to be a headache for mixed-topology and multiple sections. We may have to restore reading the data twice (once before  the SetChart
785   // call to get this right but continuing for now with single section, single topology, one zone.
786   // establish element ranges for my rank
787   PetscInt    mystarte, myende, mystartv, myendv, myownede, myownedv;
788   PetscLayout elem_map, vtx_map;
789   PetscCall(PetscLayoutCreateFromSizes(comm, PETSC_DECIDE, NCells, 1, &elem_map));
790   PetscCall(PetscLayoutCreateFromSizes(comm, PETSC_DECIDE, NVertices, 1, &vtx_map));
791   PetscCall(PetscLayoutGetRange(elem_map, &mystarte, &myende));
792   PetscCall(PetscLayoutGetLocalSize(elem_map, &myownede));
793   PetscCall(PetscLayoutGetRange(vtx_map, &mystartv, &myendv));
794   PetscCall(PetscLayoutGetLocalSize(vtx_map, &myownedv));
795 
796   // -- Build Plex in parallel
797   DMPolytopeType dm_cell_type = DM_POLYTOPE_UNKNOWN;
798   PetscInt       pOrder = 1, numClosure = -1;
799   cgsize_t      *elements;
800   {
801     int        nsections;
802     PetscInt  *elementsQ1, numCorners = -1;
803     const int *perm;
804     cgsize_t   start, end; // Throwaway
805 
806     cg_nsections(cgid, B, z, &nsections);
807     // Read element connectivity
808     for (int index_sect = 1; index_sect <= nsections; index_sect++) {
809       int      nbndry, parentFlag;
810       PetscInt cell_dim;
811       CGNS_ENUMT(ElementType_t) cellType;
812 
813       PetscCallCGNSRead(cg_section_read(cgid, B, z, index_sect, buffer, &cellType, &start, &end, &nbndry, &parentFlag), *dm, 0);
814 
815       PetscCall(CGNSElementTypeGetTopologyInfo(cellType, &dm_cell_type, &numCorners, &cell_dim));
816       // Skip over element that are not max dimension (ie. boundary elements)
817       if (cell_dim != dim) continue;
818       PetscCall(CGNSElementTypeGetDiscretizationInfo(cellType, &numClosure, &pOrder));
819       PetscCall(PetscMalloc1(myownede * numClosure, &elements));
820       PetscCallCGNSReadData(cgp_elements_read_data(cgid, B, z, index_sect, mystarte + 1, myende, elements), *dm, 0);
821       for (PetscInt v = 0; v < myownede * numClosure; ++v) elements[v] -= 1; // 0 based
822       break;
823     }
824 
825     // Create corners-only connectivity
826     PetscCall(PetscMalloc1(myownede * numCorners, &elementsQ1));
827     PetscCall(DMPlexCGNSGetPermutation_Internal(dm_cell_type, numCorners, NULL, &perm));
828     for (PetscInt e = 0; e < myownede; ++e) {
829       for (PetscInt v = 0; v < numCorners; ++v) elementsQ1[e * numCorners + perm[v]] = elements[e * numClosure + v];
830     }
831 
832     // Build cell-vertex Plex
833     PetscCall(DMPlexBuildFromCellListParallel(*dm, myownede, myownedv, NVertices, numCorners, elementsQ1, NULL, NULL));
834     PetscCall(DMViewFromOptions(*dm, NULL, "-corner_dm_view"));
835     PetscCall(PetscFree(elementsQ1));
836   }
837 
838   if (interpolate) PetscCall(DMPlexInterpolateInPlace_Internal(*dm));
839 
840   // -- Create SF for naive nodal-data read to elements
841   PetscSF plex_to_cgns_sf;
842   {
843     PetscInt     nleaves, num_comp;
844     PetscInt    *leaf, num_leaves = 0;
845     PetscInt     cStart, cEnd;
846     const int   *perm;
847     PetscSF      cgns_to_local_sf;
848     PetscSection local_section;
849     PetscFE      fe;
850 
851     // sfNatural requires PetscSection to handle DMDistribute, so we use PetscFE to define the section
852     // Use number of components = 1 to work with just the nodes themselves
853     PetscCall(PetscFECreateLagrangeByCell(PETSC_COMM_SELF, dim, 1, dm_cell_type, pOrder, PETSC_DETERMINE, &fe));
854     PetscCall(PetscObjectSetName((PetscObject)fe, "FE for sfNatural"));
855     PetscCall(DMAddField(*dm, NULL, (PetscObject)fe));
856     PetscCall(DMCreateDS(*dm));
857     PetscCall(PetscFEDestroy(&fe));
858 
859     PetscCall(DMGetLocalSection(*dm, &local_section));
860     PetscCall(PetscSectionViewFromOptions(local_section, NULL, "-fe_natural_section_view"));
861     PetscCall(PetscSectionGetFieldComponents(local_section, 0, &num_comp));
862     PetscCall(PetscSectionGetStorageSize(local_section, &nleaves));
863     nleaves /= num_comp;
864     PetscCall(PetscMalloc1(nleaves, &leaf));
865     for (PetscInt i = 0; i < nleaves; i++) leaf[i] = -1;
866 
867     // Get the permutation from CGNS closure numbering to PLEX closure numbering
868     PetscCall(DMPlexCGNSGetPermutation_Internal(dm_cell_type, numClosure, NULL, &perm));
869     PetscCall(DMPlexGetHeightStratum(*dm, 0, &cStart, &cEnd));
870     for (PetscInt cell = cStart; cell < cEnd; ++cell) {
871       PetscInt num_closure_dof, *closure_idx = NULL;
872 
873       PetscCall(DMPlexGetClosureIndices(*dm, local_section, local_section, cell, PETSC_FALSE, &num_closure_dof, &closure_idx, NULL, NULL));
874       PetscAssert(numClosure * num_comp == num_closure_dof, comm, PETSC_ERR_PLIB, "Closure dof size does not match polytope");
875       for (PetscInt i = 0; i < numClosure; i++) {
876         PetscInt li = closure_idx[perm[i] * num_comp] / num_comp;
877         if (li < 0) continue;
878 
879         PetscInt cgns_idx = elements[cell * numClosure + i];
880         if (leaf[li] == -1) {
881           leaf[li] = cgns_idx;
882           num_leaves++;
883         } else PetscAssert(leaf[li] == cgns_idx, PETSC_COMM_SELF, PETSC_ERR_PLIB, "leaf does not match previously set");
884       }
885       PetscCall(DMPlexRestoreClosureIndices(*dm, local_section, local_section, cell, PETSC_FALSE, &num_closure_dof, &closure_idx, NULL, NULL));
886     }
887     PetscAssert(num_leaves == nleaves, PETSC_COMM_SELF, PETSC_ERR_PLIB, "leaf count in closure does not match nleaves");
888     PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)*dm), &cgns_to_local_sf));
889     PetscCall(PetscSFSetGraphLayout(cgns_to_local_sf, vtx_map, nleaves, NULL, PETSC_USE_POINTER, leaf));
890     PetscCall(PetscObjectSetName((PetscObject)cgns_to_local_sf, "CGNS to Plex SF"));
891     PetscCall(PetscSFViewFromOptions(cgns_to_local_sf, NULL, "-CGNStoPlex_sf_view"));
892     PetscCall(PetscFree(leaf));
893     PetscCall(PetscFree(elements));
894 
895     { // Convert cgns_to_local to global_to_cgns
896       PetscSF sectionsf, cgns_to_global_sf;
897 
898       PetscCall(DMGetSectionSF(*dm, &sectionsf));
899       PetscCall(PetscSFComposeInverse(cgns_to_local_sf, sectionsf, &cgns_to_global_sf));
900       PetscCall(PetscSFDestroy(&cgns_to_local_sf));
901       PetscCall(PetscSFCreateInverseSF(cgns_to_global_sf, &plex_to_cgns_sf));
902       PetscCall(PetscObjectSetName((PetscObject)plex_to_cgns_sf, "Global Plex to CGNS"));
903       PetscCall(PetscSFDestroy(&cgns_to_global_sf));
904     }
905   }
906 
907   { // -- Set coordinates for DM
908     PetscScalar *coords;
909     float       *x[3];
910     double      *xd[3];
911     PetscBool    read_with_double;
912     PetscFE      cfe;
913 
914     // Setup coordinate space first. Use pOrder here for isoparametric; revisit with CPEX-0045 High Order.
915     PetscCall(PetscFECreateLagrangeByCell(PETSC_COMM_SELF, dim, coordDim, dm_cell_type, pOrder, PETSC_DETERMINE, &cfe));
916     PetscCall(DMSetCoordinateDisc(*dm, cfe, PETSC_FALSE, PETSC_FALSE));
917     PetscCall(PetscFEDestroy(&cfe));
918 
919     { // Determine if coords are written in single or double precision
920       CGNS_ENUMT(DataType_t) datatype;
921 
922       PetscCallCGNSRead(cg_coord_info(cgid, B, z, 1, &datatype, buffer), *dm, 0);
923       read_with_double = datatype == CGNS_ENUMV(RealDouble) ? PETSC_TRUE : PETSC_FALSE;
924     }
925 
926     // Read coords from file and set into component-major ordering
927     if (read_with_double) PetscCall(PetscMalloc3(myownedv, &xd[0], myownedv, &xd[1], myownedv, &xd[2]));
928     else PetscCall(PetscMalloc3(myownedv, &x[0], myownedv, &x[1], myownedv, &x[2]));
929     PetscCall(PetscMalloc1(myownedv * coordDim, &coords));
930     {
931       cgsize_t sizes[3]; /* Number of vertices, number of cells, number of boundary vertices */
932       cgsize_t range_min[3] = {mystartv + 1, 1, 1};
933       cgsize_t range_max[3] = {myendv, 1, 1};
934       int      ngrids, ncoords;
935 
936       PetscCallCGNSRead(cg_zone_read(cgid, B, z, buffer, sizes), *dm, 0);
937       PetscCallCGNSRead(cg_ngrids(cgid, B, z, &ngrids), *dm, 0);
938       PetscCheck(ngrids <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single grid, not %d", ngrids);
939       PetscCallCGNSRead(cg_ncoords(cgid, B, z, &ncoords), *dm, 0);
940       PetscCheck(ncoords == coordDim, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a coordinate array for each dimension, not %d", ncoords);
941       if (read_with_double) {
942         for (int d = 0; d < coordDim; ++d) PetscCallCGNSReadData(cgp_coord_read_data(cgid, B, z, (d + 1), range_min, range_max, xd[d]), *dm, 0);
943         if (coordDim >= 1) {
944           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 0] = xd[0][v];
945         }
946         if (coordDim >= 2) {
947           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 1] = xd[1][v];
948         }
949         if (coordDim >= 3) {
950           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 2] = xd[2][v];
951         }
952       } else {
953         for (int d = 0; d < coordDim; ++d) PetscCallCGNSReadData(cgp_coord_read_data(cgid, 1, z, (d + 1), range_min, range_max, x[d]), *dm, 0);
954         if (coordDim >= 1) {
955           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 0] = x[0][v];
956         }
957         if (coordDim >= 2) {
958           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 1] = x[1][v];
959         }
960         if (coordDim >= 3) {
961           for (PetscInt v = 0; v < myownedv; ++v) coords[v * coordDim + 2] = x[2][v];
962         }
963       }
964     }
965     if (read_with_double) PetscCall(PetscFree3(xd[0], xd[1], xd[2]));
966     else PetscCall(PetscFree3(x[0], x[1], x[2]));
967 
968     { // Reduce CGNS-ordered coordinate nodes to Plex ordering, and set DM's coordinates
969       Vec          coord_global;
970       MPI_Datatype unit;
971       PetscScalar *coord_global_array;
972       DM           cdm;
973 
974       PetscCall(DMGetCoordinateDM(*dm, &cdm));
975       PetscCall(DMCreateGlobalVector(cdm, &coord_global));
976       PetscCall(VecGetArrayWrite(coord_global, &coord_global_array));
977       PetscCallMPI(MPI_Type_contiguous(coordDim, MPIU_SCALAR, &unit));
978       PetscCallMPI(MPI_Type_commit(&unit));
979       PetscCall(PetscSFReduceBegin(plex_to_cgns_sf, unit, coords, coord_global_array, MPI_REPLACE));
980       PetscCall(PetscSFReduceEnd(plex_to_cgns_sf, unit, coords, coord_global_array, MPI_REPLACE));
981       PetscCall(VecRestoreArrayWrite(coord_global, &coord_global_array));
982       PetscCallMPI(MPI_Type_free(&unit));
983       PetscCall(DMSetCoordinates(*dm, coord_global));
984       PetscCall(VecDestroy(&coord_global));
985     }
986     PetscCall(PetscFree(coords));
987   }
988 
989   // -- Set sfNatural for solution vectors in CGNS file
990   // NOTE: We set sfNatural to be the map between the original CGNS ordering of nodes and the Plex ordering of nodes.
991   PetscCall(PetscSFViewFromOptions(plex_to_cgns_sf, NULL, "-sfNatural_init_view"));
992   PetscCall(DMSetNaturalSF(*dm, plex_to_cgns_sf));
993   PetscCall(DMSetUseNatural(*dm, PETSC_TRUE));
994   PetscCall(PetscSFDestroy(&plex_to_cgns_sf));
995 
996   PetscCall(PetscLayoutDestroy(&elem_map));
997   PetscCall(PetscLayoutDestroy(&vtx_map));
998   PetscFunctionReturn(PETSC_SUCCESS);
999 }
1000 
1001 // node_l2g must be freed
1002 static PetscErrorCode DMPlexCreateNodeNumbering(DM dm, PetscInt *num_local_nodes, PetscInt *num_global_nodes, PetscInt *nStart, PetscInt *nEnd, const PetscInt **node_l2g)
1003 {
1004   PetscSection    local_section;
1005   PetscSF         point_sf;
1006   PetscInt        pStart, pEnd, spStart, spEnd, *points, nleaves, ncomp, *nodes;
1007   PetscMPIInt     comm_size;
1008   const PetscInt *ilocal, field = 0;
1009 
1010   PetscFunctionBegin;
1011   *num_local_nodes  = -1;
1012   *num_global_nodes = -1;
1013   *nStart           = -1;
1014   *nEnd             = -1;
1015   *node_l2g         = NULL;
1016 
1017   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &comm_size));
1018   PetscCall(DMGetLocalSection(dm, &local_section));
1019   PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
1020   PetscCall(PetscSectionGetChart(local_section, &spStart, &spEnd));
1021   PetscCall(DMGetPointSF(dm, &point_sf));
1022   if (comm_size == 1) nleaves = 0;
1023   else PetscCall(PetscSFGetGraph(point_sf, NULL, &nleaves, &ilocal, NULL));
1024   PetscCall(PetscSectionGetFieldComponents(local_section, field, &ncomp));
1025 
1026   PetscInt local_node = 0, owned_node = 0, owned_start = 0;
1027   for (PetscInt p = spStart, leaf = 0; p < spEnd; p++) {
1028     PetscInt dof;
1029     PetscCall(PetscSectionGetFieldDof(local_section, p, field, &dof));
1030     PetscAssert(dof % ncomp == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Field dof %" PetscInt_FMT " must be divisible by components %" PetscInt_FMT, dof, ncomp);
1031     local_node += dof / ncomp;
1032     if (leaf < nleaves && p == ilocal[leaf]) { // skip points owned by a different process
1033       leaf++;
1034     } else {
1035       owned_node += dof / ncomp;
1036     }
1037   }
1038   PetscCallMPI(MPI_Exscan(&owned_node, &owned_start, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)dm)));
1039   PetscCall(PetscMalloc1(pEnd - pStart, &points));
1040   owned_node = 0;
1041   for (PetscInt p = spStart, leaf = 0; p < spEnd; p++) {
1042     if (leaf < nleaves && p == ilocal[leaf]) { // skip points owned by a different process
1043       points[p - pStart] = -1;
1044       leaf++;
1045       continue;
1046     }
1047     PetscInt dof, offset;
1048     PetscCall(PetscSectionGetFieldDof(local_section, p, field, &dof));
1049     PetscCall(PetscSectionGetFieldOffset(local_section, p, field, &offset));
1050     PetscAssert(offset % ncomp == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Field offset %" PetscInt_FMT " must be divisible by components %" PetscInt_FMT, offset, ncomp);
1051     points[p - pStart] = owned_start + owned_node;
1052     owned_node += dof / ncomp;
1053   }
1054   if (comm_size > 1) {
1055     PetscCall(PetscSFBcastBegin(point_sf, MPIU_INT, points, points, MPI_REPLACE));
1056     PetscCall(PetscSFBcastEnd(point_sf, MPIU_INT, points, points, MPI_REPLACE));
1057   }
1058 
1059   // Set up global indices for each local node
1060   PetscCall(PetscMalloc1(local_node, &nodes));
1061   for (PetscInt p = spStart; p < spEnd; p++) {
1062     PetscInt dof, offset;
1063     PetscCall(PetscSectionGetFieldDof(local_section, p, field, &dof));
1064     PetscCall(PetscSectionGetFieldOffset(local_section, p, field, &offset));
1065     for (PetscInt n = 0; n < dof / ncomp; n++) nodes[offset / ncomp + n] = points[p - pStart] + n;
1066   }
1067   PetscCall(PetscFree(points));
1068   *num_local_nodes = local_node;
1069   *nStart          = owned_start;
1070   *nEnd            = owned_start + owned_node;
1071   PetscCallMPI(MPIU_Allreduce(&owned_node, num_global_nodes, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)dm)));
1072   *node_l2g = nodes;
1073   PetscFunctionReturn(PETSC_SUCCESS);
1074 }
1075 
1076 PetscErrorCode DMView_PlexCGNS(DM dm, PetscViewer viewer)
1077 {
1078   PetscViewer_CGNS *cgv = (PetscViewer_CGNS *)viewer->data;
1079   PetscInt          fvGhostStart;
1080   PetscInt          topo_dim, coord_dim, num_global_elems;
1081   PetscInt          cStart, cEnd, num_local_nodes, num_global_nodes, nStart, nEnd;
1082   const PetscInt   *node_l2g;
1083   Vec               coord;
1084   DM                colloc_dm, cdm;
1085   PetscMPIInt       size;
1086   const char       *dm_name;
1087   int               base, zone;
1088   cgsize_t          isize[3];
1089 
1090   PetscFunctionBegin;
1091   if (!cgv->file_num) {
1092     PetscInt time_step;
1093     PetscCall(DMGetOutputSequenceNumber(dm, &time_step, NULL));
1094     PetscCall(PetscViewerCGNSFileOpen_Internal(viewer, time_step));
1095   }
1096   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
1097   PetscCall(DMGetDimension(dm, &topo_dim));
1098   PetscCall(DMGetCoordinateDim(dm, &coord_dim));
1099   PetscCall(PetscObjectGetName((PetscObject)dm, &dm_name));
1100   PetscCallCGNSWrite(cg_base_write(cgv->file_num, dm_name, topo_dim, coord_dim, &base), dm, viewer);
1101   PetscCallCGNS(cg_goto(cgv->file_num, base, NULL));
1102   PetscCallCGNSWrite(cg_dataclass_write(CGNS_ENUMV(NormalizedByDimensional)), dm, viewer);
1103 
1104   {
1105     PetscFE        fe, fe_coord;
1106     PetscClassId   ds_id;
1107     PetscDualSpace dual_space, dual_space_coord;
1108     PetscInt       num_fields, field_order = -1, field_order_coord;
1109     PetscBool      is_simplex;
1110     PetscCall(DMGetNumFields(dm, &num_fields));
1111     if (num_fields > 0) {
1112       PetscCall(DMGetField(dm, 0, NULL, (PetscObject *)&fe));
1113       PetscCall(PetscObjectGetClassId((PetscObject)fe, &ds_id));
1114       if (ds_id != PETSCFE_CLASSID) {
1115         fe = NULL;
1116         if (ds_id == PETSCFV_CLASSID) field_order = -1; // use whatever is present for coords; field will be CellCenter
1117         else field_order = 1;                           // assume vertex-based linear elements
1118       }
1119     } else fe = NULL;
1120     if (fe) {
1121       PetscCall(PetscFEGetDualSpace(fe, &dual_space));
1122       PetscCall(PetscDualSpaceGetOrder(dual_space, &field_order));
1123     }
1124     PetscCall(DMGetCoordinateDM(dm, &cdm));
1125     PetscCall(DMGetField(cdm, 0, NULL, (PetscObject *)&fe_coord));
1126     {
1127       PetscClassId id;
1128       PetscCall(PetscObjectGetClassId((PetscObject)fe_coord, &id));
1129       if (id != PETSCFE_CLASSID) fe_coord = NULL;
1130     }
1131     if (fe_coord) {
1132       PetscCall(PetscFEGetDualSpace(fe_coord, &dual_space_coord));
1133       PetscCall(PetscDualSpaceGetOrder(dual_space_coord, &field_order_coord));
1134     } else field_order_coord = 1;
1135     if (field_order > 0 && field_order != field_order_coord) {
1136       PetscInt quadrature_order = field_order;
1137       PetscCall(DMClone(dm, &colloc_dm));
1138       { // Inform the new colloc_dm that it is a coordinate DM so isoperiodic affine corrections can be applied
1139         const PetscSF *face_sfs;
1140         PetscInt       num_face_sfs;
1141         PetscCall(DMPlexGetIsoperiodicFaceSF(dm, &num_face_sfs, &face_sfs));
1142         PetscCall(DMPlexSetIsoperiodicFaceSF(colloc_dm, num_face_sfs, (PetscSF *)face_sfs));
1143         if (face_sfs) colloc_dm->periodic.setup = DMPeriodicCoordinateSetUp_Internal;
1144       }
1145       PetscCall(DMPlexIsSimplex(dm, &is_simplex));
1146       PetscCall(PetscFECreateLagrange(PetscObjectComm((PetscObject)dm), topo_dim, coord_dim, is_simplex, field_order, quadrature_order, &fe));
1147       PetscCall(DMSetCoordinateDisc(colloc_dm, fe, PETSC_FALSE, PETSC_TRUE));
1148       PetscCall(PetscFEDestroy(&fe));
1149     } else {
1150       PetscCall(PetscObjectReference((PetscObject)dm));
1151       colloc_dm = dm;
1152     }
1153   }
1154   PetscCall(DMGetCoordinateDM(colloc_dm, &cdm));
1155   PetscCall(DMPlexCreateNodeNumbering(cdm, &num_local_nodes, &num_global_nodes, &nStart, &nEnd, &node_l2g));
1156   PetscCall(DMGetCoordinatesLocal(colloc_dm, &coord));
1157   PetscCall(DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd));
1158   PetscCall(DMPlexGetCellTypeStratum(dm, DM_POLYTOPE_FV_GHOST, &fvGhostStart, NULL));
1159   if (fvGhostStart >= 0) cEnd = fvGhostStart;
1160   num_global_elems = cEnd - cStart;
1161   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &num_global_elems, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)dm)));
1162   isize[0] = num_global_nodes;
1163   isize[1] = num_global_elems;
1164   isize[2] = 0;
1165   PetscCallCGNSWrite(cg_zone_write(cgv->file_num, base, "Zone", isize, CGNS_ENUMV(Unstructured), &zone), dm, viewer);
1166 
1167   {
1168     const PetscScalar *X;
1169     PetscScalar       *x;
1170     int                coord_ids[3];
1171 
1172     PetscCall(VecGetArrayRead(coord, &X));
1173     for (PetscInt d = 0; d < coord_dim; d++) {
1174       const double exponents[] = {0, 1, 0, 0, 0};
1175       char         coord_name[64];
1176       PetscCall(PetscSNPrintf(coord_name, sizeof coord_name, "Coordinate%c", 'X' + (int)d));
1177       PetscCallCGNSWrite(cgp_coord_write(cgv->file_num, base, zone, CGNS_ENUMV(RealDouble), coord_name, &coord_ids[d]), dm, viewer);
1178       PetscCallCGNS(cg_goto(cgv->file_num, base, "Zone_t", zone, "GridCoordinates", 0, coord_name, 0, NULL));
1179       PetscCallCGNSWrite(cg_exponents_write(CGNS_ENUMV(RealDouble), exponents), dm, viewer);
1180     }
1181 
1182     int        section;
1183     cgsize_t   e_owned, e_global, e_start, *conn = NULL;
1184     const int *perm;
1185     CGNS_ENUMT(ElementType_t) element_type = CGNS_ENUMV(ElementTypeNull);
1186     {
1187       PetscCall(PetscMalloc1(nEnd - nStart, &x));
1188       for (PetscInt d = 0; d < coord_dim; d++) {
1189         for (PetscInt n = 0; n < num_local_nodes; n++) {
1190           PetscInt gn = node_l2g[n];
1191           if (gn < nStart || nEnd <= gn) continue;
1192           x[gn - nStart] = X[n * coord_dim + d];
1193         }
1194         // CGNS nodes use 1-based indexing
1195         cgsize_t start = nStart + 1, end = nEnd;
1196         PetscCallCGNSWriteData(cgp_coord_write_data(cgv->file_num, base, zone, coord_ids[d], &start, &end, x), dm, viewer);
1197       }
1198       PetscCall(PetscFree(x));
1199       PetscCall(VecRestoreArrayRead(coord, &X));
1200     }
1201 
1202     e_owned = cEnd - cStart;
1203     if (e_owned > 0) {
1204       DMPolytopeType cell_type;
1205 
1206       PetscCall(DMPlexGetCellType(dm, cStart, &cell_type));
1207       for (PetscInt i = cStart, c = 0; i < cEnd; i++) {
1208         PetscInt closure_dof, *closure_indices, elem_size;
1209 
1210         PetscCall(DMPlexGetClosureIndices(cdm, cdm->localSection, cdm->localSection, i, PETSC_FALSE, &closure_dof, &closure_indices, NULL, NULL));
1211         elem_size = closure_dof / coord_dim;
1212         if (!conn) PetscCall(PetscMalloc1(e_owned * elem_size, &conn));
1213         PetscCall(DMPlexCGNSGetPermutation_Internal(cell_type, closure_dof / coord_dim, &element_type, &perm));
1214         for (PetscInt j = 0; j < elem_size; j++) conn[c++] = node_l2g[closure_indices[perm[j] * coord_dim] / coord_dim] + 1;
1215         PetscCall(DMPlexRestoreClosureIndices(cdm, cdm->localSection, cdm->localSection, i, PETSC_FALSE, &closure_dof, &closure_indices, NULL, NULL));
1216       }
1217     }
1218 
1219     { // Get global element_type (for ranks that do not have owned elements)
1220       PetscInt local_element_type, global_element_type;
1221 
1222       local_element_type = e_owned > 0 ? element_type : -1;
1223       PetscCallMPI(MPIU_Allreduce(&local_element_type, &global_element_type, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)viewer)));
1224       if (local_element_type != -1) PetscCheck(local_element_type == global_element_type, PETSC_COMM_SELF, PETSC_ERR_SUP, "Ranks with different element types not supported");
1225       element_type = (CGNS_ENUMT(ElementType_t))global_element_type;
1226     }
1227     PetscCallMPI(MPIU_Allreduce(&e_owned, &e_global, 1, MPIU_CGSIZE, MPI_SUM, PetscObjectComm((PetscObject)dm)));
1228     PetscCheck(e_global == num_global_elems, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unexpected number of elements %" PRIdCGSIZE " vs %" PetscInt_FMT, e_global, num_global_elems);
1229     e_start = 0;
1230     PetscCallMPI(MPI_Exscan(&e_owned, &e_start, 1, MPIU_CGSIZE, MPI_SUM, PetscObjectComm((PetscObject)dm)));
1231     PetscCallCGNSWrite(cgp_section_write(cgv->file_num, base, zone, "Elem", element_type, 1, e_global, 0, &section), dm, viewer);
1232     PetscCallCGNSWriteData(cgp_elements_write_data(cgv->file_num, base, zone, section, e_start + 1, e_start + e_owned, conn), dm, viewer);
1233     PetscCall(PetscFree(conn));
1234 
1235     cgv->base            = base;
1236     cgv->zone            = zone;
1237     cgv->node_l2g        = node_l2g;
1238     cgv->num_local_nodes = num_local_nodes;
1239     cgv->nStart          = nStart;
1240     cgv->nEnd            = nEnd;
1241     cgv->eStart          = e_start;
1242     cgv->eEnd            = e_start + e_owned;
1243     if (1) {
1244       PetscMPIInt rank;
1245       int        *efield;
1246       int         sol, field;
1247       DMLabel     label;
1248       PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
1249       PetscCall(PetscMalloc1(e_owned, &efield));
1250       for (PetscInt i = 0; i < e_owned; i++) efield[i] = rank;
1251       PetscCallCGNSWrite(cg_sol_write(cgv->file_num, base, zone, "CellInfo", CGNS_ENUMV(CellCenter), &sol), dm, viewer);
1252       PetscCallCGNSWrite(cgp_field_write(cgv->file_num, base, zone, sol, CGNS_ENUMV(Integer), "Rank", &field), dm, viewer);
1253       cgsize_t start = e_start + 1, end = e_start + e_owned;
1254       PetscCallCGNSWriteData(cgp_field_write_data(cgv->file_num, base, zone, sol, field, &start, &end, efield), dm, viewer);
1255       PetscCall(DMGetLabel(dm, "Cell Sets", &label));
1256       if (label) {
1257         for (PetscInt c = cStart; c < cEnd; c++) {
1258           PetscInt value;
1259           PetscCall(DMLabelGetValue(label, c, &value));
1260           efield[c - cStart] = value;
1261         }
1262         PetscCallCGNSWrite(cgp_field_write(cgv->file_num, base, zone, sol, CGNS_ENUMV(Integer), "CellSet", &field), dm, viewer);
1263         PetscCallCGNSWriteData(cgp_field_write_data(cgv->file_num, base, zone, sol, field, &start, &end, efield), dm, viewer);
1264       }
1265       PetscCall(PetscFree(efield));
1266     }
1267   }
1268   PetscCall(DMDestroy(&colloc_dm));
1269   PetscFunctionReturn(PETSC_SUCCESS);
1270 }
1271 
1272 PetscErrorCode VecView_Plex_Local_CGNS(Vec V, PetscViewer viewer)
1273 {
1274   PetscViewer_CGNS  *cgv = (PetscViewer_CGNS *)viewer->data;
1275   DM                 dm;
1276   PetscSection       section;
1277   PetscInt           time_step, num_fields, pStart, pEnd, fvGhostStart;
1278   PetscReal          time, *time_slot;
1279   size_t            *step_slot;
1280   const PetscScalar *v;
1281   char               solution_name[PETSC_MAX_PATH_LEN];
1282   int                sol;
1283 
1284   PetscFunctionBegin;
1285   PetscCall(VecGetDM(V, &dm));
1286   PetscCall(DMGetLocalSection(dm, &section));
1287   PetscCall(PetscSectionGetChart(section, &pStart, &pEnd));
1288   PetscCall(DMPlexGetCellTypeStratum(dm, DM_POLYTOPE_FV_GHOST, &fvGhostStart, NULL));
1289   if (fvGhostStart >= 0) pEnd = fvGhostStart;
1290 
1291   if (!cgv->node_l2g) PetscCall(DMView(dm, viewer));
1292   if (!cgv->grid_loc) { // Determine if writing to cell-centers or to nodes
1293     PetscInt cStart, cEnd;
1294     PetscInt local_grid_loc, global_grid_loc;
1295 
1296     PetscCall(DMPlexGetHeightStratum(dm, 0, &cStart, &cEnd));
1297     if (fvGhostStart >= 0) cEnd = fvGhostStart;
1298     if (cgv->num_local_nodes == 0) local_grid_loc = -1;
1299     else if (cStart == pStart && cEnd == pEnd) local_grid_loc = CGNS_ENUMV(CellCenter);
1300     else local_grid_loc = CGNS_ENUMV(Vertex);
1301 
1302     PetscCallMPI(MPIU_Allreduce(&local_grid_loc, &global_grid_loc, 1, MPIU_INT, MPI_MAX, PetscObjectComm((PetscObject)viewer)));
1303     if (local_grid_loc != -1)
1304       PetscCheck(local_grid_loc == global_grid_loc, PETSC_COMM_SELF, PETSC_ERR_SUP, "Ranks with different grid locations not supported. Local has %" PetscInt_FMT ", allreduce returned %" PetscInt_FMT, local_grid_loc, global_grid_loc);
1305     PetscCheck((global_grid_loc == CGNS_ENUMV(CellCenter)) || (global_grid_loc == CGNS_ENUMV(Vertex)), PetscObjectComm((PetscObject)viewer), PETSC_ERR_SUP, "Grid location should only be CellCenter (%d) or Vertex(%d), but have %" PetscInt_FMT, CGNS_ENUMV(CellCenter), CGNS_ENUMV(Vertex), global_grid_loc);
1306     cgv->grid_loc = (CGNS_ENUMT(GridLocation_t))global_grid_loc;
1307   }
1308   if (!cgv->nodal_field) {
1309     switch (cgv->grid_loc) {
1310     case CGNS_ENUMV(Vertex): {
1311       PetscCall(PetscMalloc1(cgv->nEnd - cgv->nStart, &cgv->nodal_field));
1312     } break;
1313     case CGNS_ENUMV(CellCenter): {
1314       PetscCall(PetscMalloc1(cgv->eEnd - cgv->eStart, &cgv->nodal_field));
1315     } break;
1316     default:
1317       SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Can only write for Vertex and CellCenter grid locations");
1318     }
1319   }
1320   if (!cgv->output_times) PetscCall(PetscSegBufferCreate(sizeof(PetscReal), 20, &cgv->output_times));
1321   if (!cgv->output_steps) PetscCall(PetscSegBufferCreate(sizeof(size_t), 20, &cgv->output_steps));
1322 
1323   PetscCall(DMGetOutputSequenceNumber(dm, &time_step, &time));
1324   if (time_step < 0) {
1325     time_step = 0;
1326     time      = 0.;
1327   }
1328   // Avoid "Duplicate child name found" error by not writing an already-written solution.
1329   // This usually occurs when a solution is written and then diverges on the very next timestep.
1330   if (time_step == cgv->previous_output_step) PetscFunctionReturn(PETSC_SUCCESS);
1331 
1332   PetscCall(PetscSegBufferGet(cgv->output_times, 1, &time_slot));
1333   *time_slot = time;
1334   PetscCall(PetscSegBufferGet(cgv->output_steps, 1, &step_slot));
1335   *step_slot = cgv->previous_output_step = time_step;
1336   PetscCall(PetscSNPrintf(solution_name, sizeof solution_name, "FlowSolution%" PetscInt_FMT, time_step));
1337   PetscCallCGNSWrite(cg_sol_write(cgv->file_num, cgv->base, cgv->zone, solution_name, cgv->grid_loc, &sol), V, viewer);
1338   PetscCall(VecGetArrayRead(V, &v));
1339   PetscCall(PetscSectionGetNumFields(section, &num_fields));
1340   for (PetscInt field = 0; field < num_fields; field++) {
1341     PetscInt    ncomp;
1342     const char *field_name;
1343     PetscCall(PetscSectionGetFieldName(section, field, &field_name));
1344     PetscCall(PetscSectionGetFieldComponents(section, field, &ncomp));
1345     for (PetscInt comp = 0; comp < ncomp; comp++) {
1346       int         cgfield;
1347       const char *comp_name;
1348       char        cgns_field_name[32]; // CGNS max field name is 32
1349       CGNS_ENUMT(DataType_t) datatype;
1350       PetscCall(PetscSectionGetComponentName(section, field, comp, &comp_name));
1351       if (ncomp == 1 && comp_name[0] == '0' && comp_name[1] == '\0' && field_name[0] != '\0') PetscCall(PetscStrncpy(cgns_field_name, field_name, sizeof cgns_field_name));
1352       else if (field_name[0] == '\0') PetscCall(PetscStrncpy(cgns_field_name, comp_name, sizeof cgns_field_name));
1353       else PetscCall(PetscSNPrintf(cgns_field_name, sizeof cgns_field_name, "%s.%s", field_name, comp_name));
1354       PetscCall(PetscCGNSDataType(PETSC_SCALAR, &datatype));
1355       PetscCallCGNSWrite(cgp_field_write(cgv->file_num, cgv->base, cgv->zone, sol, datatype, cgns_field_name, &cgfield), V, viewer);
1356       for (PetscInt p = pStart, n = 0; p < pEnd; p++) {
1357         PetscInt off, dof;
1358         PetscCall(PetscSectionGetFieldDof(section, p, field, &dof));
1359         if (dof == 0) continue;
1360         PetscCall(PetscSectionGetFieldOffset(section, p, field, &off));
1361         for (PetscInt c = comp; c < dof; c += ncomp, n++) {
1362           switch (cgv->grid_loc) {
1363           case CGNS_ENUMV(Vertex): {
1364             PetscInt gn = cgv->node_l2g[n];
1365             if (gn < cgv->nStart || cgv->nEnd <= gn) continue;
1366             cgv->nodal_field[gn - cgv->nStart] = v[off + c];
1367           } break;
1368           case CGNS_ENUMV(CellCenter): {
1369             cgv->nodal_field[n] = v[off + c];
1370           } break;
1371           default:
1372             SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Can only pack for Vertex and CellCenter grid locations");
1373           }
1374         }
1375       }
1376       // CGNS nodes use 1-based indexing
1377       cgsize_t start, end;
1378       switch (cgv->grid_loc) {
1379       case CGNS_ENUMV(Vertex): {
1380         start = cgv->nStart + 1;
1381         end   = cgv->nEnd;
1382       } break;
1383       case CGNS_ENUMV(CellCenter): {
1384         start = cgv->eStart + 1;
1385         end   = cgv->eEnd;
1386       } break;
1387       default:
1388         SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Can only write for Vertex and CellCenter grid locations");
1389       }
1390       PetscCallCGNSWriteData(cgp_field_write_data(cgv->file_num, cgv->base, cgv->zone, sol, cgfield, &start, &end, cgv->nodal_field), V, viewer);
1391     }
1392   }
1393   PetscCall(VecRestoreArrayRead(V, &v));
1394   PetscCall(PetscViewerCGNSCheckBatch_Internal(viewer));
1395   PetscFunctionReturn(PETSC_SUCCESS);
1396 }
1397 
1398 PetscErrorCode VecLoad_Plex_CGNS_Internal(Vec V, PetscViewer viewer)
1399 {
1400   MPI_Comm          comm;
1401   char              buffer[CGIO_MAX_NAME_LENGTH + 1];
1402   PetscViewer_CGNS *cgv                 = (PetscViewer_CGNS *)viewer->data;
1403   int               cgid                = cgv->file_num;
1404   PetscBool         use_parallel_viewer = PETSC_FALSE;
1405   int               z                   = 1; // Only support one zone
1406   int               B                   = 1; // Only support one base
1407   int               numComp;
1408   PetscInt          V_numComps, mystartv, myendv, myownedv;
1409 
1410   PetscFunctionBeginUser;
1411   PetscCall(PetscObjectGetComm((PetscObject)V, &comm));
1412 
1413   PetscCall(PetscOptionsGetBool(NULL, NULL, "-dm_plex_cgns_parallel", &use_parallel_viewer, NULL));
1414   PetscCheck(use_parallel_viewer, comm, PETSC_ERR_USER_INPUT, "Cannot use VecLoad with CGNS file in serial reader; use -dm_plex_cgns_parallel to enable parallel reader");
1415 
1416   { // Get CGNS node ownership information
1417     int         nbases, nzones;
1418     PetscInt    NVertices;
1419     PetscLayout vtx_map;
1420     cgsize_t    sizes[3]; /* Number of vertices, number of cells, number of boundary vertices */
1421 
1422     PetscCallCGNSRead(cg_nbases(cgid, &nbases), V, viewer);
1423     PetscCheck(nbases <= 1, PETSC_COMM_SELF, PETSC_ERR_LIB, "CGNS file must have a single base, not %d", nbases);
1424     PetscCallCGNSRead(cg_nzones(cgid, B, &nzones), V, viewer);
1425     PetscCheck(nzones == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "limited to one zone %d", (int)nzones);
1426 
1427     PetscCallCGNSRead(cg_zone_read(cgid, B, z, buffer, sizes), V, viewer);
1428     NVertices = sizes[0];
1429 
1430     PetscCall(PetscLayoutCreateFromSizes(comm, PETSC_DECIDE, NVertices, 1, &vtx_map));
1431     PetscCall(PetscLayoutGetRange(vtx_map, &mystartv, &myendv));
1432     PetscCall(PetscLayoutGetLocalSize(vtx_map, &myownedv));
1433     PetscCall(PetscLayoutDestroy(&vtx_map));
1434   }
1435 
1436   { // -- Read data from file into Vec
1437     PetscScalar *fields = NULL;
1438     PetscSF      sfNatural;
1439 
1440     { // Check compatibility between sfNatural and the data source and sink
1441       DM       dm;
1442       PetscInt nleaves, nroots, V_local_size;
1443 
1444       PetscCall(VecGetDM(V, &dm));
1445       PetscCall(DMGetNaturalSF(dm, &sfNatural));
1446       PetscCheck(sfNatural, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "DM of Vec must have sfNatural");
1447       PetscCall(PetscSFGetGraph(sfNatural, &nroots, &nleaves, NULL, NULL));
1448       PetscCall(VecGetLocalSize(V, &V_local_size));
1449       PetscCheck(nleaves == myownedv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Number of locally owned vertices (% " PetscInt_FMT ") must match number of leaves in sfNatural (% " PetscInt_FMT ")", myownedv, nleaves);
1450       PetscCheck(V_local_size % nroots == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Local Vec size (% " PetscInt_FMT ") not evenly divisible by number of roots in sfNatural (% " PetscInt_FMT ")", V_local_size, nroots);
1451       V_numComps = V_local_size / nroots;
1452     }
1453 
1454     { // Read data into component-major ordering
1455       int isol, numSols;
1456       CGNS_ENUMT(DataType_t) datatype;
1457       double *fields_CGNS;
1458 
1459       PetscCallCGNSRead(cg_nsols(cgid, B, z, &numSols), V, viewer);
1460       PetscCall(PetscViewerCGNSGetSolutionFileIndex_Internal(viewer, &isol));
1461       PetscCallCGNSRead(cg_nfields(cgid, B, z, isol, &numComp), V, viewer);
1462       PetscCheck(V_numComps == numComp, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Vec sized for  % " PetscInt_FMT " components per node, but file has %d components per node", V_numComps, numComp);
1463 
1464       cgsize_t range_min[3] = {mystartv + 1, 1, 1};
1465       cgsize_t range_max[3] = {myendv, 1, 1};
1466       PetscCall(PetscMalloc1(myownedv * numComp, &fields_CGNS));
1467       PetscCall(PetscMalloc1(myownedv * numComp, &fields));
1468       for (int d = 0; d < numComp; ++d) {
1469         PetscCallCGNSRead(cg_field_info(cgid, B, z, isol, (d + 1), &datatype, buffer), V, viewer);
1470         PetscCheck(datatype == CGNS_ENUMV(RealDouble), PETSC_COMM_SELF, PETSC_ERR_ARG_NOTSAMETYPE, "Field %s in file is not of type double", buffer);
1471         PetscCallCGNSReadData(cgp_field_read_data(cgid, B, z, isol, (d + 1), range_min, range_max, &fields_CGNS[d * myownedv]), V, viewer);
1472       }
1473       for (int d = 0; d < numComp; ++d) {
1474         for (PetscInt v = 0; v < myownedv; ++v) fields[v * numComp + d] = fields_CGNS[d * myownedv + v];
1475       }
1476       PetscCall(PetscFree(fields_CGNS));
1477     }
1478 
1479     { // Reduce fields into Vec array
1480       PetscScalar *V_array;
1481       MPI_Datatype fieldtype;
1482 
1483       PetscCall(VecGetArrayWrite(V, &V_array));
1484       PetscCallMPI(MPI_Type_contiguous(numComp, MPIU_SCALAR, &fieldtype));
1485       PetscCallMPI(MPI_Type_commit(&fieldtype));
1486       PetscCall(PetscSFReduceBegin(sfNatural, fieldtype, fields, V_array, MPI_REPLACE));
1487       PetscCall(PetscSFReduceEnd(sfNatural, fieldtype, fields, V_array, MPI_REPLACE));
1488       PetscCallMPI(MPI_Type_free(&fieldtype));
1489       PetscCall(VecRestoreArrayWrite(V, &V_array));
1490     }
1491     PetscCall(PetscFree(fields));
1492   }
1493   PetscFunctionReturn(PETSC_SUCCESS);
1494 }
1495