xref: /petsc/include/petscis.h (revision 98d129c30f3ee9fdddc40fdbc5a989b7be64f888)
1 /*
2    An index set is a generalization of a subset of integers.  Index sets
3    are used for defining scatters and gathers.
4 */
5 #pragma once
6 
7 #include <petscsys.h>
8 #include <petscsftypes.h>
9 #include <petscsectiontypes.h>
10 #include <petscistypes.h> /*I  "petscis.h" I*/
11 
12 /* SUBMANSEC = IS */
13 
14 #define IS_FILE_CLASSID 1211218
15 PETSC_EXTERN PetscClassId IS_CLASSID;
16 
17 PETSC_EXTERN PetscErrorCode ISInitializePackage(void);
18 PETSC_EXTERN PetscErrorCode ISFinalizePackage(void);
19 
20 /*J
21     ISType - String with the name of a PETSc index set type
22 
23    Values:
24 +  `ISGENERAL` - the values are stored with an array of indices and generally have no structure
25 .  `ISSTRIDE`  - the values have a simple structure of an initial offset and then a step size between values
26 -  `ISBLOCK`   - values are an array of indices, each representing a block (of the same common length) of values
27 
28    Level: beginner
29 
30 .seealso: `ISSetType()`, `IS`, `ISCreateGeneral()`, `ISCreateStride()`, `ISCreateBlock()`, `ISCreate()`, `ISRegister()`,
31           `VecScatterCreate()`, `MatGetSubMatrices()`
32 J*/
33 typedef const char *ISType;
34 #define ISGENERAL "general"
35 #define ISSTRIDE  "stride"
36 #define ISBLOCK   "block"
37 
38 /* Dynamic creation and loading functions */
39 PETSC_EXTERN PetscFunctionList ISList;
40 PETSC_EXTERN PetscErrorCode    ISSetType(IS, ISType);
41 PETSC_EXTERN PetscErrorCode    ISGetType(IS, ISType *);
42 PETSC_EXTERN PetscErrorCode    ISRegister(const char[], PetscErrorCode (*)(IS));
43 PETSC_EXTERN PetscErrorCode    ISRegisterAll(void);
44 PETSC_EXTERN PetscErrorCode    ISCreate(MPI_Comm, IS *);
45 
46 PETSC_EXTERN PetscErrorCode ISDestroy(IS *);
47 PETSC_EXTERN PetscErrorCode ISSetPermutation(IS);
48 PETSC_EXTERN PetscErrorCode ISPermutation(IS, PetscBool *);
49 PETSC_EXTERN PetscErrorCode ISSetIdentity(IS);
50 PETSC_EXTERN PetscErrorCode ISIdentity(IS, PetscBool *);
51 PETSC_EXTERN PetscErrorCode ISContiguousLocal(IS, PetscInt, PetscInt, PetscInt *, PetscBool *);
52 
53 /*E
54    ISInfo - Info that may either be computed or set as known for an index set
55 
56    Level: intermediate
57 
58    Developer Note:
59    Entries that are negative need not be called collectively by all processes.
60 
61 .seealso: `IS`, `ISType`, `ISSetInfo()`
62 E*/
63 typedef enum {
64   IS_INFO_MIN    = -1,
65   IS_SORTED      = 0,
66   IS_UNIQUE      = 1,
67   IS_PERMUTATION = 2,
68   IS_INTERVAL    = 3,
69   IS_IDENTITY    = 4,
70   IS_INFO_MAX    = 5
71 } ISInfo;
72 
73 typedef enum {
74   IS_LOCAL,
75   IS_GLOBAL
76 } ISInfoType;
77 
78 PETSC_EXTERN PetscErrorCode ISSetInfo(IS, ISInfo, ISInfoType, PetscBool, PetscBool);
79 PETSC_EXTERN PetscErrorCode ISGetInfo(IS, ISInfo, ISInfoType, PetscBool, PetscBool *);
80 PETSC_EXTERN PetscErrorCode ISClearInfoCache(IS, PetscBool);
81 PETSC_EXTERN PetscErrorCode ISGetIndices(IS, const PetscInt *[]);
82 PETSC_EXTERN PetscErrorCode ISRestoreIndices(IS, const PetscInt *[]);
83 PETSC_EXTERN PetscErrorCode ISGetTotalIndices(IS, const PetscInt *[]);
84 PETSC_EXTERN PetscErrorCode ISRestoreTotalIndices(IS, const PetscInt *[]);
85 PETSC_EXTERN PetscErrorCode ISGetNonlocalIndices(IS, const PetscInt *[]);
86 PETSC_EXTERN PetscErrorCode ISRestoreNonlocalIndices(IS, const PetscInt *[]);
87 PETSC_EXTERN PetscErrorCode ISGetNonlocalIS(IS, IS *);
88 PETSC_EXTERN PetscErrorCode ISRestoreNonlocalIS(IS, IS *);
89 PETSC_EXTERN PetscErrorCode ISGetSize(IS, PetscInt *);
90 PETSC_EXTERN PetscErrorCode ISGetLocalSize(IS, PetscInt *);
91 PETSC_EXTERN PetscErrorCode ISInvertPermutation(IS, PetscInt, IS *);
92 PETSC_EXTERN PetscErrorCode ISView(IS, PetscViewer);
93 PETSC_EXTERN PetscErrorCode ISViewFromOptions(IS, PetscObject, const char[]);
94 PETSC_EXTERN PetscErrorCode ISLoad(IS, PetscViewer);
95 PETSC_EXTERN PetscErrorCode ISEqual(IS, IS, PetscBool *);
96 PETSC_EXTERN PetscErrorCode ISEqualUnsorted(IS, IS, PetscBool *);
97 PETSC_EXTERN PetscErrorCode ISSort(IS);
98 PETSC_EXTERN PetscErrorCode ISSortRemoveDups(IS);
99 PETSC_EXTERN PetscErrorCode ISSorted(IS, PetscBool *);
100 PETSC_EXTERN PetscErrorCode ISDifference(IS, IS, IS *);
101 PETSC_EXTERN PetscErrorCode ISSum(IS, IS, IS *);
102 PETSC_EXTERN PetscErrorCode ISExpand(IS, IS, IS *);
103 PETSC_EXTERN PetscErrorCode ISIntersect(IS, IS, IS *);
104 PETSC_EXTERN PetscErrorCode ISGetMinMax(IS, PetscInt *, PetscInt *);
105 
106 PETSC_EXTERN PetscErrorCode ISLocate(IS, PetscInt, PetscInt *);
107 PETSC_EXTERN PetscErrorCode ISGetPointRange(IS, PetscInt *, PetscInt *, const PetscInt **);
108 PETSC_EXTERN PetscErrorCode ISRestorePointRange(IS, PetscInt *, PetscInt *, const PetscInt **);
109 PETSC_EXTERN PetscErrorCode ISGetPointSubrange(IS, PetscInt, PetscInt, const PetscInt *);
110 
111 PETSC_EXTERN PetscErrorCode ISGetBlockSize(IS, PetscInt *);
112 PETSC_EXTERN PetscErrorCode ISSetBlockSize(IS, PetscInt);
113 
114 PETSC_EXTERN PetscErrorCode ISToGeneral(IS);
115 
116 PETSC_EXTERN PetscErrorCode ISDuplicate(IS, IS *);
117 PETSC_EXTERN PetscErrorCode ISCopy(IS, IS);
118 PETSC_EXTERN PetscErrorCode ISShift(IS, PetscInt, IS);
119 PETSC_EXTERN PetscErrorCode ISAllGather(IS, IS *);
120 PETSC_EXTERN PetscErrorCode ISComplement(IS, PetscInt, PetscInt, IS *);
121 PETSC_EXTERN PetscErrorCode ISConcatenate(MPI_Comm, PetscInt, const IS[], IS *);
122 PETSC_EXTERN PetscErrorCode ISListToPair(MPI_Comm, PetscInt, IS[], IS *, IS *);
123 PETSC_EXTERN PetscErrorCode ISPairToList(IS, IS, PetscInt *, IS *[]);
124 PETSC_EXTERN PetscErrorCode ISEmbed(IS, IS, PetscBool, IS *);
125 PETSC_EXTERN PetscErrorCode ISSortPermutation(IS, PetscBool, IS *);
126 PETSC_EXTERN PetscErrorCode ISOnComm(IS, MPI_Comm, PetscCopyMode, IS *);
127 PETSC_EXTERN PetscErrorCode ISRenumber(IS, IS, PetscInt *, IS *);
128 PETSC_EXTERN PetscErrorCode ISCreateSubIS(IS, IS, IS *);
129 
130 /* ISGENERAL specific */
131 PETSC_EXTERN PetscErrorCode ISCreateGeneral(MPI_Comm, PetscInt, const PetscInt[], PetscCopyMode, IS *);
132 PETSC_EXTERN PetscErrorCode ISGeneralSetIndices(IS, PetscInt, const PetscInt[], PetscCopyMode);
133 PETSC_EXTERN PetscErrorCode ISGeneralSetIndicesFromMask(IS, PetscInt, PetscInt, const PetscBool[]);
134 PETSC_EXTERN PetscErrorCode ISGeneralFilter(IS, PetscInt, PetscInt);
135 
136 /* ISBLOCK specific */
137 PETSC_EXTERN PetscErrorCode ISCreateBlock(MPI_Comm, PetscInt, PetscInt, const PetscInt[], PetscCopyMode, IS *);
138 PETSC_EXTERN PetscErrorCode ISBlockSetIndices(IS, PetscInt, PetscInt, const PetscInt[], PetscCopyMode);
139 PETSC_EXTERN PetscErrorCode ISBlockGetIndices(IS, const PetscInt *[]);
140 PETSC_EXTERN PetscErrorCode ISBlockRestoreIndices(IS, const PetscInt *[]);
141 PETSC_EXTERN PetscErrorCode ISBlockGetLocalSize(IS, PetscInt *);
142 PETSC_EXTERN PetscErrorCode ISBlockGetSize(IS, PetscInt *);
143 
144 /* ISSTRIDE specific */
145 PETSC_EXTERN PetscErrorCode ISCreateStride(MPI_Comm, PetscInt, PetscInt, PetscInt, IS *);
146 PETSC_EXTERN PetscErrorCode ISStrideSetStride(IS, PetscInt, PetscInt, PetscInt);
147 PETSC_EXTERN PetscErrorCode ISStrideGetInfo(IS, PetscInt *, PetscInt *);
148 
149 #define IS_LTOGM_FILE_CLASSID 1211217
150 PETSC_EXTERN PetscClassId IS_LTOGM_CLASSID;
151 
152 /*E
153    ISGlobalToLocalMappingMode - Indicates mapping behavior if global indices are missing
154 
155    Values:
156 +  `IS_GTOLM_MASK` - missing global indices are masked by mapping them to a local index of -1
157 -  `IS_GTOLM_DROP` - missing global indices are dropped
158 
159    Level: beginner
160 
161 .seealso: `ISGlobalToLocalMappingApplyBlock()`, `ISGlobalToLocalMappingApply()`
162 E*/
163 typedef enum {
164   IS_GTOLM_MASK,
165   IS_GTOLM_DROP
166 } ISGlobalToLocalMappingMode;
167 
168 /*J
169    ISLocalToGlobalMappingType - String with the name of a mapping method
170 
171    Values:
172 +  `ISLOCALTOGLOBALMAPPINGBASIC` - a non-memory scalable way of storing `ISLocalToGlobalMapping` that allows applying `ISGlobalToLocalMappingApply()` efficiently
173 -  `ISLOCALTOGLOBALMAPPINGHASH`  - a memory scalable way of storing `ISLocalToGlobalMapping` that allows applying `ISGlobalToLocalMappingApply()` reasonably efficiently
174 
175    Level: beginner
176 
177 .seealso: `ISLocalToGlobalMapping`, `ISLocalToGlobalMappingSetType()`, `ISLocalToGlobalSetFromOptions()`, `ISGlobalToLocalMappingMode`
178 J*/
179 typedef const char *ISLocalToGlobalMappingType;
180 #define ISLOCALTOGLOBALMAPPINGBASIC "basic"
181 #define ISLOCALTOGLOBALMAPPINGHASH  "hash"
182 
183 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingSetType(ISLocalToGlobalMapping, ISLocalToGlobalMappingType);
184 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetType(ISLocalToGlobalMapping, ISLocalToGlobalMappingType *);
185 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRegister(const char[], PetscErrorCode (*)(ISLocalToGlobalMapping));
186 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRegisterAll(void);
187 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingCreate(MPI_Comm, PetscInt, PetscInt, const PetscInt[], PetscCopyMode, ISLocalToGlobalMapping *);
188 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingCreateIS(IS, ISLocalToGlobalMapping *);
189 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingCreateSF(PetscSF, PetscInt, ISLocalToGlobalMapping *);
190 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingSetFromOptions(ISLocalToGlobalMapping);
191 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingSetUp(ISLocalToGlobalMapping);
192 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingView(ISLocalToGlobalMapping, PetscViewer);
193 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingLoad(ISLocalToGlobalMapping, PetscViewer);
194 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingViewFromOptions(ISLocalToGlobalMapping, PetscObject, const char[]);
195 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingConcatenate(MPI_Comm, PetscInt, const ISLocalToGlobalMapping[], ISLocalToGlobalMapping *);
196 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingDuplicate(ISLocalToGlobalMapping, ISLocalToGlobalMapping *);
197 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingDestroy(ISLocalToGlobalMapping *);
198 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetSize(ISLocalToGlobalMapping, PetscInt *);
199 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetIndices(ISLocalToGlobalMapping, const PetscInt **);
200 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreIndices(ISLocalToGlobalMapping, const PetscInt **);
201 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetBlockIndices(ISLocalToGlobalMapping, const PetscInt **);
202 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreBlockIndices(ISLocalToGlobalMapping, const PetscInt **);
203 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetBlockSize(ISLocalToGlobalMapping, PetscInt *);
204 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingSetBlockSize(ISLocalToGlobalMapping, PetscInt);
205 
206 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingApply(ISLocalToGlobalMapping, PetscInt, const PetscInt[], PetscInt[]);
207 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingApplyBlock(ISLocalToGlobalMapping, PetscInt, const PetscInt[], PetscInt[]);
208 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingApplyIS(ISLocalToGlobalMapping, IS, IS *);
209 PETSC_EXTERN PetscErrorCode ISGlobalToLocalMappingApply(ISLocalToGlobalMapping, ISGlobalToLocalMappingMode, PetscInt, const PetscInt[], PetscInt *, PetscInt[]);
210 PETSC_EXTERN PetscErrorCode ISGlobalToLocalMappingApplyBlock(ISLocalToGlobalMapping, ISGlobalToLocalMappingMode, PetscInt, const PetscInt[], PetscInt *, PetscInt[]);
211 PETSC_EXTERN PetscErrorCode ISGlobalToLocalMappingApplyIS(ISLocalToGlobalMapping, ISGlobalToLocalMappingMode, IS, IS *);
212 
213 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetNodeInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt **[]);
214 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreNodeInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt **[]);
215 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt *[], PetscInt **[]);
216 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt *[], PetscInt **[]);
217 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetBlockNodeInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt **[]);
218 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreBlockNodeInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt **[]);
219 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetBlockInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt *[], PetscInt **[]);
220 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingRestoreBlockInfo(ISLocalToGlobalMapping, PetscInt *, PetscInt *[], PetscInt *[], PetscInt **[]);
221 PETSC_EXTERN PetscErrorCode ISLocalToGlobalMappingGetBlockMultiLeavesSF(ISLocalToGlobalMapping, PetscSF *);
222 
223 /*E
224    ISColoringType - determines if the coloring is for the entire parallel grid/graph/matrix
225                     or for just the local ghosted portion
226 
227    Values:
228 +  `IS_COLORING_GLOBAL` - does not include the colors for ghost points, this is used when the function
229                           is called synchronously in parallel. This requires generating a "parallel coloring".
230 -  `IS_COLORING_LOCAL`  - includes colors for ghost points, this is used when the function can be called
231                           separately on individual processes with the ghost points already filled in. Does not
232                           require a "parallel coloring", rather each process colors its local + ghost part.
233                           Using this can result in much less parallel communication. Currently only works
234                           with `DMDA` and if you call `MatFDColoringSetFunction()` with the local function.
235 
236    Level: beginner
237 
238 .seealso: `ISColoring`, `ISColoringSetType()`, `ISColoringGetType()`, `DMCreateColoring()`
239 E*/
240 typedef enum {
241   IS_COLORING_GLOBAL,
242   IS_COLORING_LOCAL
243 } ISColoringType;
244 
245 PETSC_EXTERN const char *const                ISColoringTypes[];
246 typedef unsigned PETSC_IS_COLORING_VALUE_TYPE ISColoringValue;
247 #define IS_COLORING_MAX     PETSC_IS_COLORING_MAX
248 #define MPIU_COLORING_VALUE PETSC_MPIU_IS_COLORING_VALUE_TYPE
249 PETSC_EXTERN PetscErrorCode ISAllGatherColors(MPI_Comm, PetscInt, ISColoringValue *, PetscInt *, ISColoringValue *[]);
250 
251 PETSC_EXTERN PetscErrorCode ISColoringCreate(MPI_Comm, PetscInt, PetscInt, const ISColoringValue[], PetscCopyMode, ISColoring *);
252 PETSC_EXTERN PetscErrorCode ISColoringDestroy(ISColoring *);
253 PETSC_EXTERN PetscErrorCode ISColoringView(ISColoring, PetscViewer);
254 PETSC_EXTERN PetscErrorCode ISColoringViewFromOptions(ISColoring, PetscObject, const char[]);
255 PETSC_EXTERN PetscErrorCode ISColoringGetIS(ISColoring, PetscCopyMode, PetscInt *, IS *[]);
256 PETSC_EXTERN PetscErrorCode ISColoringRestoreIS(ISColoring, PetscCopyMode, IS *[]);
257 PETSC_EXTERN PetscErrorCode ISColoringReference(ISColoring);
258 PETSC_EXTERN PetscErrorCode ISColoringSetType(ISColoring, ISColoringType);
259 PETSC_EXTERN PetscErrorCode ISColoringGetType(ISColoring, ISColoringType *);
260 PETSC_EXTERN PetscErrorCode ISColoringGetColors(ISColoring, PetscInt *, PetscInt *, const ISColoringValue **);
261 
262 PETSC_EXTERN PetscErrorCode ISBuildTwoSided(IS, IS, IS *);
263 PETSC_EXTERN PetscErrorCode ISPartitioningToNumbering(IS, IS *);
264 PETSC_EXTERN PetscErrorCode ISPartitioningCount(IS, PetscInt, PetscInt[]);
265 
266 PETSC_EXTERN PetscErrorCode ISCompressIndicesGeneral(PetscInt, PetscInt, PetscInt, PetscInt, const IS[], IS[]);
267 PETSC_DEPRECATED_FUNCTION(3, 19, 0, "ISCompressIndicesGeneral()", ) static inline PetscErrorCode ISCompressIndicesSorted(PetscInt n, PetscInt bs, PetscInt imax, const IS is_in[], IS is_out[])
268 {
269   return ISCompressIndicesGeneral(n, bs, n, imax, is_in, is_out);
270 }
271 PETSC_EXTERN PetscErrorCode ISExpandIndicesGeneral(PetscInt, PetscInt, PetscInt, PetscInt, const IS[], IS[]);
272 
273 struct _n_PetscLayout {
274   MPI_Comm               comm;
275   PetscMPIInt            size;
276   PetscInt               n, N;         /* local, global vector size */
277   PetscInt               rstart, rend; /* local start, local end + 1 */
278   PetscInt              *range;        /* the offset of each processor */
279   PetscBool              range_alloc;  /* should range be freed in Destroy? */
280   PetscInt               bs;           /* number of elements in each block (generally for multi-component
281                                        * problems). Defaults to -1 and can be arbitrarily lazy so always use
282                                        * PetscAbs(map->bs) when accessing directly and expecting result to be
283                                        * positive. Do NOT multiply above numbers by bs */
284   PetscInt               refcnt;       /* MPI Vecs obtained with VecDuplicate() and from MatCreateVecs() reuse map of input object */
285   ISLocalToGlobalMapping mapping;      /* mapping used in Vec/MatSetValuesLocal() */
286   PetscBool              setupcalled;  /* Forbid setup more than once */
287   PetscInt               oldn, oldN;   /* Checking if setup is allowed */
288   PetscInt               oldbs;        /* And again */
289 };
290 
291 /*@C
292    PetscLayoutFindOwner - Find the owning MPI process for a global index
293 
294    Not Collective; No Fortran Support
295 
296    Input Parameters:
297 +  map - the layout
298 -  idx - global index to find the owner of
299 
300    Output Parameter:
301 .  owner - the owning rank
302 
303    Level: developer
304 
305 .seealso: `PetscLayout`, `PetscLayoutFindOwnerIndex()`
306 @*/
307 static inline PetscErrorCode PetscLayoutFindOwner(PetscLayout map, PetscInt idx, PetscMPIInt *owner)
308 {
309   PetscMPIInt lo = 0, hi, t;
310 
311   PetscFunctionBegin;
312   *owner = -1; /* GCC erroneously issues warning about possibly uninitialized use when error condition */
313   PetscAssert((map->n >= 0) && (map->N >= 0) && (map->range), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "PetscLayoutSetUp() must be called first");
314   PetscAssert(idx >= 0 && idx <= map->N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Index %" PetscInt_FMT " is out of range", idx);
315   hi = map->size;
316   while (hi - lo > 1) {
317     t = lo + (hi - lo) / 2;
318     if (idx < map->range[t]) hi = t;
319     else lo = t;
320   }
321   *owner = lo;
322   PetscFunctionReturn(PETSC_SUCCESS);
323 }
324 
325 /*@C
326     PetscLayoutFindOwnerIndex - Find the owning MPI process and the local index on that process for a global index
327 
328     Not Collective; No Fortran Support
329 
330    Input Parameters:
331 +  map   - the layout
332 -  idx   - global index to find the owner of
333 
334    Output Parameters:
335 +  owner - the owning rank
336 -  lidx  - local index used by the owner for `idx`
337 
338    Level: developer
339 
340 .seealso: `PetscLayout`, `PetscLayoutFindOwner()`
341 @*/
342 static inline PetscErrorCode PetscLayoutFindOwnerIndex(PetscLayout map, PetscInt idx, PetscMPIInt *owner, PetscInt *lidx)
343 {
344   PetscMPIInt lo = 0, hi, t;
345 
346   PetscFunctionBegin;
347   PetscAssert((map->n >= 0) && (map->N >= 0) && (map->range), PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "PetscLayoutSetUp() must be called first");
348   PetscAssert(idx >= 0 && idx <= map->N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Index %" PetscInt_FMT " is out of range", idx);
349   hi = map->size;
350   while (hi - lo > 1) {
351     t = lo + (hi - lo) / 2;
352     if (idx < map->range[t]) hi = t;
353     else lo = t;
354   }
355   if (owner) *owner = lo;
356   if (lidx) *lidx = idx - map->range[lo];
357   PetscFunctionReturn(PETSC_SUCCESS);
358 }
359 
360 PETSC_EXTERN PetscErrorCode PetscLayoutCreate(MPI_Comm, PetscLayout *);
361 PETSC_EXTERN PetscErrorCode PetscLayoutCreateFromSizes(MPI_Comm, PetscInt, PetscInt, PetscInt, PetscLayout *);
362 PETSC_EXTERN PetscErrorCode PetscLayoutCreateFromRanges(MPI_Comm, const PetscInt[], PetscCopyMode, PetscInt, PetscLayout *);
363 PETSC_EXTERN PetscErrorCode PetscLayoutSetUp(PetscLayout);
364 PETSC_EXTERN PetscErrorCode PetscLayoutDestroy(PetscLayout *);
365 PETSC_EXTERN PetscErrorCode PetscLayoutDuplicate(PetscLayout, PetscLayout *);
366 PETSC_EXTERN PetscErrorCode PetscLayoutReference(PetscLayout, PetscLayout *);
367 PETSC_EXTERN PetscErrorCode PetscLayoutSetLocalSize(PetscLayout, PetscInt);
368 PETSC_EXTERN PetscErrorCode PetscLayoutGetLocalSize(PetscLayout, PetscInt *);
369 PETSC_EXTERN PetscErrorCode PetscLayoutSetSize(PetscLayout, PetscInt);
370 PETSC_EXTERN PetscErrorCode PetscLayoutGetSize(PetscLayout, PetscInt *);
371 PETSC_EXTERN PetscErrorCode PetscLayoutSetBlockSize(PetscLayout, PetscInt);
372 PETSC_EXTERN PetscErrorCode PetscLayoutGetBlockSize(PetscLayout, PetscInt *);
373 PETSC_EXTERN PetscErrorCode PetscLayoutGetRange(PetscLayout, PetscInt *, PetscInt *);
374 PETSC_EXTERN PetscErrorCode PetscLayoutGetRanges(PetscLayout, const PetscInt *[]);
375 PETSC_EXTERN PetscErrorCode PetscLayoutCompare(PetscLayout, PetscLayout, PetscBool *);
376 PETSC_EXTERN PetscErrorCode PetscLayoutSetISLocalToGlobalMapping(PetscLayout, ISLocalToGlobalMapping);
377 PETSC_EXTERN PetscErrorCode PetscLayoutMapLocal(PetscLayout, PetscInt, const PetscInt[], PetscInt *, PetscInt **, PetscInt **);
378 
379 PETSC_EXTERN PetscErrorCode PetscParallelSortInt(PetscLayout, PetscLayout, PetscInt *, PetscInt *);
380 
381 PETSC_EXTERN PetscErrorCode ISGetLayout(IS, PetscLayout *);
382 PETSC_EXTERN PetscErrorCode ISSetLayout(IS, PetscLayout);
383