xref: /petsc/src/vec/is/sf/impls/basic/sfpack.c (revision 15229ffc342989b2bf0590a733d92c152a3348fc)
1 #include <petsc/private/sfimpl.h>
2 #include <../src/vec/is/sf/impls/basic/sfpack.h>
3 #include <../src/vec/is/sf/impls/basic/sfbasic.h>
4 
5 /* This is a C file that contains packing facilities, with dispatches to device if enabled. */
6 
7 /*
8  * MPI_Reduce_local is not really useful because it can't handle sparse data and it vectorizes "in the wrong direction",
9  * therefore we pack data types manually. This file defines packing routines for the standard data types.
10  */
11 
12 #define CPPJoin4(a, b, c, d) a##_##b##_##c##_##d
13 
14 /* Operations working like s += t */
15 #define OP_BINARY(op, s, t) \
16   do { \
17     (s) = (s)op(t); \
18   } while (0) /* binary ops in the middle such as +, *, && etc. */
19 #define OP_FUNCTION(op, s, t) \
20   do { \
21     (s) = op((s), (t)); \
22   } while (0) /* ops like a function, such as PetscMax, PetscMin */
23 #define OP_LXOR(op, s, t) \
24   do { \
25     (s) = (!(s)) != (!(t)); \
26   } while (0) /* logical exclusive OR */
27 #define OP_ASSIGN(op, s, t) \
28   do { \
29     (s) = (t); \
30   } while (0)
31 /* Ref MPI MAXLOC */
32 #define OP_XLOC(op, s, t) \
33   do { \
34     if ((s).u == (t).u) (s).i = PetscMin((s).i, (t).i); \
35     else if (!((s).u op(t).u)) s = t; \
36   } while (0)
37 
38 /* DEF_PackFunc - macro defining a Pack routine
39 
40    Arguments of the macro:
41    +Type      Type of the basic data in an entry, i.e., int, PetscInt, PetscReal etc. It is not the type of an entry.
42    .BS        Block size for vectorization. It is a factor of bsz.
43    -EQ        (bs == BS) ? 1 : 0. EQ is a compile-time const to help compiler optimizations. See below.
44 
45    Arguments of the Pack routine:
46    +count     Number of indices in idx[].
47    .start     When opt and idx are NULL, it means indices are contiguous & start is the first index; otherwise, not used.
48    .opt       Per-pack optimization plan. NULL means no such plan.
49    .idx       Indices of entries to packed.
50    .link      Provide a context for the current call, such as link->bs, number of basic types in an entry. Ex. if unit is MPI_2INT, then bs=2 and the basic type is int.
51    .unpacked  Address of the unpacked data. The entries will be packed are unpacked[idx[i]],for i in [0,count).
52    -packed    Address of the packed data.
53  */
54 #define DEF_PackFunc(Type, BS, EQ) \
55   static PetscErrorCode CPPJoin4(Pack, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt start, PetscSFPackOpt opt, const PetscInt *idx, const void *unpacked, void *packed) \
56   { \
57     const Type    *u = (const Type *)unpacked, *u2; \
58     Type          *p = (Type *)packed, *p2; \
59     PetscInt       i, j, k, X, Y, r, bs = link->bs; \
60     const PetscInt M   = (EQ) ? 1 : bs / BS; /* If EQ, then M=1 enables compiler's const-propagation */ \
61     const PetscInt MBS = M * BS;             /* MBS=bs. We turn MBS into a compile time const when EQ=1. */ \
62     PetscFunctionBegin; \
63     if (!idx) PetscCall(PetscArraycpy(p, u + start * MBS, MBS * count)); /* idx[] are contiguous */ \
64     else if (opt) { /* has optimizations available */ p2 = p; \
65       for (r = 0; r < opt->n; r++) { \
66         u2 = u + opt->start[r] * MBS; \
67         X  = opt->X[r]; \
68         Y  = opt->Y[r]; \
69         for (k = 0; k < opt->dz[r]; k++) \
70           for (j = 0; j < opt->dy[r]; j++) { \
71             PetscCall(PetscArraycpy(p2, u2 + (X * Y * k + X * j) * MBS, opt->dx[r] * MBS)); \
72             p2 += opt->dx[r] * MBS; \
73           } \
74       } \
75     } else { \
76       for (i = 0; i < count; i++) \
77         for (j = 0; j < M; j++)    /* Decent compilers should eliminate this loop when M = const 1 */ \
78           for (k = 0; k < BS; k++) /* Compiler either unrolls (BS=1) or vectorizes (BS=2,4,8,etc) this loop */ \
79             p[i * MBS + j * BS + k] = u[idx[i] * MBS + j * BS + k]; \
80     } \
81     PetscFunctionReturn(PETSC_SUCCESS); \
82   }
83 
84 /* DEF_Action - macro defining a UnpackAndInsert routine that unpacks data from a contiguous buffer
85                 and inserts into a sparse array.
86 
87    Arguments:
88   .Type       Type of the data
89   .BS         Block size for vectorization
90   .EQ        (bs == BS) ? 1 : 0. EQ is a compile-time const.
91 
92   Notes:
93    This macro is not combined with DEF_ActionAndOp because we want to use memcpy in this macro.
94  */
95 #define DEF_UnpackFunc(Type, BS, EQ) \
96   static PetscErrorCode CPPJoin4(UnpackAndInsert, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt start, PetscSFPackOpt opt, const PetscInt *idx, void *unpacked, const void *packed) \
97   { \
98     Type          *u = (Type *)unpacked, *u2; \
99     const Type    *p = (const Type *)packed; \
100     PetscInt       i, j, k, X, Y, r, bs = link->bs; \
101     const PetscInt M   = (EQ) ? 1 : bs / BS; /* If EQ, then M=1 enables compiler's const-propagation */ \
102     const PetscInt MBS = M * BS;             /* MBS=bs. We turn MBS into a compile time const when EQ=1. */ \
103     PetscFunctionBegin; \
104     if (!idx) { \
105       u += start * MBS; \
106       if (u != p) PetscCall(PetscArraycpy(u, p, count *MBS)); \
107     } else if (opt) { /* has optimizations available */ \
108       for (r = 0; r < opt->n; r++) { \
109         u2 = u + opt->start[r] * MBS; \
110         X  = opt->X[r]; \
111         Y  = opt->Y[r]; \
112         for (k = 0; k < opt->dz[r]; k++) \
113           for (j = 0; j < opt->dy[r]; j++) { \
114             PetscCall(PetscArraycpy(u2 + (X * Y * k + X * j) * MBS, p, opt->dx[r] * MBS)); \
115             p += opt->dx[r] * MBS; \
116           } \
117       } \
118     } else { \
119       for (i = 0; i < count; i++) \
120         for (j = 0; j < M; j++) \
121           for (k = 0; k < BS; k++) u[idx[i] * MBS + j * BS + k] = p[i * MBS + j * BS + k]; \
122     } \
123     PetscFunctionReturn(PETSC_SUCCESS); \
124   }
125 
126 /* DEF_UnpackAndOp - macro defining a UnpackAndOp routine where Op should not be Insert
127 
128    Arguments:
129   +Opname     Name of the Op, such as Add, Mult, LAND, etc.
130   .Type       Type of the data
131   .BS         Block size for vectorization
132   .EQ         (bs == BS) ? 1 : 0. EQ is a compile-time const.
133   .Op         Operator for the op, such as +, *, &&, ||, PetscMax, PetscMin, etc.
134   .OpApply    Macro defining application of the op. Could be OP_BINARY, OP_FUNCTION, OP_LXOR
135  */
136 #define DEF_UnpackAndOp(Type, BS, EQ, Opname, Op, OpApply) \
137   static PetscErrorCode CPPJoin4(UnpackAnd##Opname, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt start, PetscSFPackOpt opt, const PetscInt *idx, void *unpacked, const void *packed) \
138   { \
139     Type          *u = (Type *)unpacked, *u2; \
140     const Type    *p = (const Type *)packed; \
141     PetscInt       i, j, k, X, Y, r, bs = link->bs; \
142     const PetscInt M   = (EQ) ? 1 : bs / BS; /* If EQ, then M=1 enables compiler's const-propagation */ \
143     const PetscInt MBS = M * BS;             /* MBS=bs. We turn MBS into a compile time const when EQ=1. */ \
144     PetscFunctionBegin; \
145     if (!idx) { \
146       u += start * MBS; \
147       for (i = 0; i < count; i++) \
148         for (j = 0; j < M; j++) \
149           for (k = 0; k < BS; k++) OpApply(Op, u[i * MBS + j * BS + k], p[i * MBS + j * BS + k]); \
150     } else if (opt) { /* idx[] has patterns */ \
151       for (r = 0; r < opt->n; r++) { \
152         u2 = u + opt->start[r] * MBS; \
153         X  = opt->X[r]; \
154         Y  = opt->Y[r]; \
155         for (k = 0; k < opt->dz[r]; k++) \
156           for (j = 0; j < opt->dy[r]; j++) { \
157             for (i = 0; i < opt->dx[r] * MBS; i++) OpApply(Op, u2[(X * Y * k + X * j) * MBS + i], p[i]); \
158             p += opt->dx[r] * MBS; \
159           } \
160       } \
161     } else { \
162       for (i = 0; i < count; i++) \
163         for (j = 0; j < M; j++) \
164           for (k = 0; k < BS; k++) OpApply(Op, u[idx[i] * MBS + j * BS + k], p[i * MBS + j * BS + k]); \
165     } \
166     PetscFunctionReturn(PETSC_SUCCESS); \
167   }
168 
169 #define DEF_FetchAndOp(Type, BS, EQ, Opname, Op, OpApply) \
170   static PetscErrorCode CPPJoin4(FetchAnd##Opname, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt start, PetscSFPackOpt opt, const PetscInt *idx, void *unpacked, void *packed) \
171   { \
172     Type          *u = (Type *)unpacked, *p = (Type *)packed, tmp; \
173     PetscInt       i, j, k, r, l, bs = link->bs; \
174     const PetscInt M   = (EQ) ? 1 : bs / BS; \
175     const PetscInt MBS = M * BS; \
176     PetscFunctionBegin; \
177     for (i = 0; i < count; i++) { \
178       r = (!idx ? start + i : idx[i]) * MBS; \
179       l = i * MBS; \
180       for (j = 0; j < M; j++) \
181         for (k = 0; k < BS; k++) { \
182           tmp = u[r + j * BS + k]; \
183           OpApply(Op, u[r + j * BS + k], p[l + j * BS + k]); \
184           p[l + j * BS + k] = tmp; \
185         } \
186     } \
187     PetscFunctionReturn(PETSC_SUCCESS); \
188   }
189 
190 #define DEF_ScatterAndOp(Type, BS, EQ, Opname, Op, OpApply) \
191   static PetscErrorCode CPPJoin4(ScatterAnd##Opname, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt srcStart, PetscSFPackOpt srcOpt, const PetscInt *srcIdx, const void *src, PetscInt dstStart, PetscSFPackOpt dstOpt, const PetscInt *dstIdx, void *dst) \
192   { \
193     const Type    *u = (const Type *)src; \
194     Type          *v = (Type *)dst; \
195     PetscInt       i, j, k, s, t, X, Y, bs = link->bs; \
196     const PetscInt M   = (EQ) ? 1 : bs / BS; \
197     const PetscInt MBS = M * BS; \
198     PetscFunctionBegin; \
199     if (!srcIdx) { /* src is contiguous */ \
200       u += srcStart * MBS; \
201       PetscCall(CPPJoin4(UnpackAnd##Opname, Type, BS, EQ)(link, count, dstStart, dstOpt, dstIdx, dst, u)); \
202     } else if (srcOpt && !dstIdx) { /* src is 3D, dst is contiguous */ \
203       u += srcOpt->start[0] * MBS; \
204       v += dstStart * MBS; \
205       X = srcOpt->X[0]; \
206       Y = srcOpt->Y[0]; \
207       for (k = 0; k < srcOpt->dz[0]; k++) \
208         for (j = 0; j < srcOpt->dy[0]; j++) { \
209           for (i = 0; i < srcOpt->dx[0] * MBS; i++) OpApply(Op, v[i], u[(X * Y * k + X * j) * MBS + i]); \
210           v += srcOpt->dx[0] * MBS; \
211         } \
212     } else { /* all other cases */ \
213       for (i = 0; i < count; i++) { \
214         s = (!srcIdx ? srcStart + i : srcIdx[i]) * MBS; \
215         t = (!dstIdx ? dstStart + i : dstIdx[i]) * MBS; \
216         for (j = 0; j < M; j++) \
217           for (k = 0; k < BS; k++) OpApply(Op, v[t + j * BS + k], u[s + j * BS + k]); \
218       } \
219     } \
220     PetscFunctionReturn(PETSC_SUCCESS); \
221   }
222 
223 #define DEF_FetchAndOpLocal(Type, BS, EQ, Opname, Op, OpApply) \
224   static PetscErrorCode CPPJoin4(FetchAnd##Opname##Local, Type, BS, EQ)(PetscSFLink link, PetscInt count, PetscInt rootstart, PetscSFPackOpt rootopt, const PetscInt *rootidx, void *rootdata, PetscInt leafstart, PetscSFPackOpt leafopt, const PetscInt *leafidx, const void *leafdata, void *leafupdate) \
225   { \
226     Type          *rdata = (Type *)rootdata, *lupdate = (Type *)leafupdate; \
227     const Type    *ldata = (const Type *)leafdata; \
228     PetscInt       i, j, k, r, l, bs = link->bs; \
229     const PetscInt M   = (EQ) ? 1 : bs / BS; \
230     const PetscInt MBS = M * BS; \
231     PetscFunctionBegin; \
232     for (i = 0; i < count; i++) { \
233       r = (rootidx ? rootidx[i] : rootstart + i) * MBS; \
234       l = (leafidx ? leafidx[i] : leafstart + i) * MBS; \
235       for (j = 0; j < M; j++) \
236         for (k = 0; k < BS; k++) { \
237           lupdate[l + j * BS + k] = rdata[r + j * BS + k]; \
238           OpApply(Op, rdata[r + j * BS + k], ldata[l + j * BS + k]); \
239         } \
240     } \
241     PetscFunctionReturn(PETSC_SUCCESS); \
242   }
243 
244 /* Pack, Unpack/Fetch ops */
245 #define DEF_Pack(Type, BS, EQ) \
246   DEF_PackFunc(Type, BS, EQ) DEF_UnpackFunc(Type, BS, EQ) DEF_ScatterAndOp(Type, BS, EQ, Insert, =, OP_ASSIGN) static void CPPJoin4(PackInit_Pack, Type, BS, EQ)(PetscSFLink link) \
247   { \
248     link->h_Pack             = CPPJoin4(Pack, Type, BS, EQ); \
249     link->h_UnpackAndInsert  = CPPJoin4(UnpackAndInsert, Type, BS, EQ); \
250     link->h_ScatterAndInsert = CPPJoin4(ScatterAndInsert, Type, BS, EQ); \
251   }
252 
253 /* Add, Mult ops */
254 #define DEF_Add(Type, BS, EQ) \
255   DEF_UnpackAndOp(Type, BS, EQ, Add, +, OP_BINARY) DEF_UnpackAndOp(Type, BS, EQ, Mult, *, OP_BINARY) DEF_FetchAndOp(Type, BS, EQ, Add, +, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, Add, +, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, Mult, *, OP_BINARY) DEF_FetchAndOpLocal(Type, BS, EQ, Add, +, OP_BINARY) static void CPPJoin4(PackInit_Add, Type, BS, EQ)(PetscSFLink link) \
256   { \
257     link->h_UnpackAndAdd     = CPPJoin4(UnpackAndAdd, Type, BS, EQ); \
258     link->h_UnpackAndMult    = CPPJoin4(UnpackAndMult, Type, BS, EQ); \
259     link->h_FetchAndAdd      = CPPJoin4(FetchAndAdd, Type, BS, EQ); \
260     link->h_ScatterAndAdd    = CPPJoin4(ScatterAndAdd, Type, BS, EQ); \
261     link->h_ScatterAndMult   = CPPJoin4(ScatterAndMult, Type, BS, EQ); \
262     link->h_FetchAndAddLocal = CPPJoin4(FetchAndAddLocal, Type, BS, EQ); \
263   }
264 
265 /* Max, Min ops */
266 #define DEF_Cmp(Type, BS, EQ) \
267   DEF_UnpackAndOp(Type, BS, EQ, Max, PetscMax, OP_FUNCTION) DEF_UnpackAndOp(Type, BS, EQ, Min, PetscMin, OP_FUNCTION) DEF_ScatterAndOp(Type, BS, EQ, Max, PetscMax, OP_FUNCTION) DEF_ScatterAndOp(Type, BS, EQ, Min, PetscMin, OP_FUNCTION) static void CPPJoin4(PackInit_Compare, Type, BS, EQ)(PetscSFLink link) \
268   { \
269     link->h_UnpackAndMax  = CPPJoin4(UnpackAndMax, Type, BS, EQ); \
270     link->h_UnpackAndMin  = CPPJoin4(UnpackAndMin, Type, BS, EQ); \
271     link->h_ScatterAndMax = CPPJoin4(ScatterAndMax, Type, BS, EQ); \
272     link->h_ScatterAndMin = CPPJoin4(ScatterAndMin, Type, BS, EQ); \
273   }
274 
275 /* Logical ops.
276   The operator in OP_LXOR should be empty but is ||. It is not used. Put here to avoid
277   the compilation warning "empty macro arguments are undefined in ISO C90"
278  */
279 #define DEF_Log(Type, BS, EQ) \
280   DEF_UnpackAndOp(Type, BS, EQ, LAND, &&, OP_BINARY) DEF_UnpackAndOp(Type, BS, EQ, LOR, ||, OP_BINARY) DEF_UnpackAndOp(Type, BS, EQ, LXOR, ||, OP_LXOR) DEF_ScatterAndOp(Type, BS, EQ, LAND, &&, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, LOR, ||, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, LXOR, ||, OP_LXOR) static void CPPJoin4(PackInit_Logical, Type, BS, EQ)(PetscSFLink link) \
281   { \
282     link->h_UnpackAndLAND  = CPPJoin4(UnpackAndLAND, Type, BS, EQ); \
283     link->h_UnpackAndLOR   = CPPJoin4(UnpackAndLOR, Type, BS, EQ); \
284     link->h_UnpackAndLXOR  = CPPJoin4(UnpackAndLXOR, Type, BS, EQ); \
285     link->h_ScatterAndLAND = CPPJoin4(ScatterAndLAND, Type, BS, EQ); \
286     link->h_ScatterAndLOR  = CPPJoin4(ScatterAndLOR, Type, BS, EQ); \
287     link->h_ScatterAndLXOR = CPPJoin4(ScatterAndLXOR, Type, BS, EQ); \
288   }
289 
290 /* Bitwise ops */
291 #define DEF_Bit(Type, BS, EQ) \
292   DEF_UnpackAndOp(Type, BS, EQ, BAND, &, OP_BINARY) DEF_UnpackAndOp(Type, BS, EQ, BOR, |, OP_BINARY) DEF_UnpackAndOp(Type, BS, EQ, BXOR, ^, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, BAND, &, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, BOR, |, OP_BINARY) DEF_ScatterAndOp(Type, BS, EQ, BXOR, ^, OP_BINARY) static void CPPJoin4(PackInit_Bitwise, Type, BS, EQ)(PetscSFLink link) \
293   { \
294     link->h_UnpackAndBAND  = CPPJoin4(UnpackAndBAND, Type, BS, EQ); \
295     link->h_UnpackAndBOR   = CPPJoin4(UnpackAndBOR, Type, BS, EQ); \
296     link->h_UnpackAndBXOR  = CPPJoin4(UnpackAndBXOR, Type, BS, EQ); \
297     link->h_ScatterAndBAND = CPPJoin4(ScatterAndBAND, Type, BS, EQ); \
298     link->h_ScatterAndBOR  = CPPJoin4(ScatterAndBOR, Type, BS, EQ); \
299     link->h_ScatterAndBXOR = CPPJoin4(ScatterAndBXOR, Type, BS, EQ); \
300   }
301 
302 /* Maxloc, Minloc ops */
303 #define DEF_Xloc(Type, BS, EQ) \
304   DEF_UnpackAndOp(Type, BS, EQ, Max, >, OP_XLOC) DEF_UnpackAndOp(Type, BS, EQ, Min, <, OP_XLOC) DEF_ScatterAndOp(Type, BS, EQ, Max, >, OP_XLOC) DEF_ScatterAndOp(Type, BS, EQ, Min, <, OP_XLOC) static void CPPJoin4(PackInit_Xloc, Type, BS, EQ)(PetscSFLink link) \
305   { \
306     link->h_UnpackAndMaxloc  = CPPJoin4(UnpackAndMax, Type, BS, EQ); \
307     link->h_UnpackAndMinloc  = CPPJoin4(UnpackAndMin, Type, BS, EQ); \
308     link->h_ScatterAndMaxloc = CPPJoin4(ScatterAndMax, Type, BS, EQ); \
309     link->h_ScatterAndMinloc = CPPJoin4(ScatterAndMin, Type, BS, EQ); \
310   }
311 
312 #define DEF_IntegerType(Type, BS, EQ) \
313   DEF_Pack(Type, BS, EQ) DEF_Add(Type, BS, EQ) DEF_Cmp(Type, BS, EQ) DEF_Log(Type, BS, EQ) DEF_Bit(Type, BS, EQ) static void CPPJoin4(PackInit_IntegerType, Type, BS, EQ)(PetscSFLink link) \
314   { \
315     CPPJoin4(PackInit_Pack, Type, BS, EQ)(link); \
316     CPPJoin4(PackInit_Add, Type, BS, EQ)(link); \
317     CPPJoin4(PackInit_Compare, Type, BS, EQ)(link); \
318     CPPJoin4(PackInit_Logical, Type, BS, EQ)(link); \
319     CPPJoin4(PackInit_Bitwise, Type, BS, EQ)(link); \
320   }
321 
322 #define DEF_RealType(Type, BS, EQ) \
323   DEF_Pack(Type, BS, EQ) DEF_Add(Type, BS, EQ) DEF_Cmp(Type, BS, EQ) static void CPPJoin4(PackInit_RealType, Type, BS, EQ)(PetscSFLink link) \
324   { \
325     CPPJoin4(PackInit_Pack, Type, BS, EQ)(link); \
326     CPPJoin4(PackInit_Add, Type, BS, EQ)(link); \
327     CPPJoin4(PackInit_Compare, Type, BS, EQ)(link); \
328   }
329 
330 #if defined(PETSC_HAVE_COMPLEX)
331   #define DEF_ComplexType(Type, BS, EQ) \
332     DEF_Pack(Type, BS, EQ) DEF_Add(Type, BS, EQ) static void CPPJoin4(PackInit_ComplexType, Type, BS, EQ)(PetscSFLink link) \
333     { \
334       CPPJoin4(PackInit_Pack, Type, BS, EQ)(link); \
335       CPPJoin4(PackInit_Add, Type, BS, EQ)(link); \
336     }
337 #endif
338 
339 #define DEF_DumbType(Type, BS, EQ) \
340   DEF_Pack(Type, BS, EQ) static void CPPJoin4(PackInit_DumbType, Type, BS, EQ)(PetscSFLink link) \
341   { \
342     CPPJoin4(PackInit_Pack, Type, BS, EQ)(link); \
343   }
344 
345 /* Maxloc, Minloc */
346 #define DEF_PairType(Type, BS, EQ) \
347   DEF_Pack(Type, BS, EQ) DEF_Xloc(Type, BS, EQ) static void CPPJoin4(PackInit_PairType, Type, BS, EQ)(PetscSFLink link) \
348   { \
349     CPPJoin4(PackInit_Pack, Type, BS, EQ)(link); \
350     CPPJoin4(PackInit_Xloc, Type, BS, EQ)(link); \
351   }
352 
353 DEF_IntegerType(PetscInt, 1, 1)   /* unit = 1 MPIU_INT  */
354   DEF_IntegerType(PetscInt, 2, 1) /* unit = 2 MPIU_INTs */
355   DEF_IntegerType(PetscInt, 4, 1) /* unit = 4 MPIU_INTs */
356   DEF_IntegerType(PetscInt, 8, 1) /* unit = 8 MPIU_INTs */
357   DEF_IntegerType(PetscInt, 1, 0) /* unit = 1*n MPIU_INTs, n>1 */
358   DEF_IntegerType(PetscInt, 2, 0) /* unit = 2*n MPIU_INTs, n>1 */
359   DEF_IntegerType(PetscInt, 4, 0) /* unit = 4*n MPIU_INTs, n>1 */
360   DEF_IntegerType(PetscInt, 8, 0) /* unit = 8*n MPIU_INTs, n>1. Routines with bigger BS are tried first. */
361 
362 #if defined(PETSC_USE_64BIT_INDICES) /* Do not need (though it is OK) to generate redundant functions if PetscInt is int */
363   DEF_IntegerType(int, 1, 1) DEF_IntegerType(int, 2, 1) DEF_IntegerType(int, 4, 1) DEF_IntegerType(int, 8, 1) DEF_IntegerType(int, 1, 0) DEF_IntegerType(int, 2, 0) DEF_IntegerType(int, 4, 0) DEF_IntegerType(int, 8, 0)
364 #endif
365 
366   /* The typedefs are used to get a typename without space that CPPJoin can handle */
367   typedef signed char SignedChar;
368 DEF_IntegerType(SignedChar, 1, 1) DEF_IntegerType(SignedChar, 2, 1) DEF_IntegerType(SignedChar, 4, 1) DEF_IntegerType(SignedChar, 8, 1) DEF_IntegerType(SignedChar, 1, 0) DEF_IntegerType(SignedChar, 2, 0) DEF_IntegerType(SignedChar, 4, 0) DEF_IntegerType(SignedChar, 8, 0)
369 
370   typedef unsigned char UnsignedChar;
371 DEF_IntegerType(UnsignedChar, 1, 1) DEF_IntegerType(UnsignedChar, 2, 1) DEF_IntegerType(UnsignedChar, 4, 1) DEF_IntegerType(UnsignedChar, 8, 1) DEF_IntegerType(UnsignedChar, 1, 0) DEF_IntegerType(UnsignedChar, 2, 0) DEF_IntegerType(UnsignedChar, 4, 0) DEF_IntegerType(UnsignedChar, 8, 0)
372 
373   DEF_RealType(PetscReal, 1, 1) DEF_RealType(PetscReal, 2, 1) DEF_RealType(PetscReal, 4, 1) DEF_RealType(PetscReal, 8, 1) DEF_RealType(PetscReal, 1, 0) DEF_RealType(PetscReal, 2, 0) DEF_RealType(PetscReal, 4, 0) DEF_RealType(PetscReal, 8, 0)
374 #if defined(PETSC_HAVE_COMPLEX)
375     DEF_ComplexType(PetscComplex, 1, 1) DEF_ComplexType(PetscComplex, 2, 1) DEF_ComplexType(PetscComplex, 4, 1) DEF_ComplexType(PetscComplex, 8, 1) DEF_ComplexType(PetscComplex, 1, 0) DEF_ComplexType(PetscComplex, 2, 0) DEF_ComplexType(PetscComplex, 4, 0) DEF_ComplexType(PetscComplex, 8, 0)
376 #endif
377 
378 #define PairType(Type1, Type2) Type1##_##Type2
379       typedef struct {
380   int u;
381   int i;
382 } PairType(int, int);
383 typedef struct {
384   PetscInt u;
385   PetscInt i;
386 } PairType(PetscInt, PetscInt);
387 DEF_PairType(PairType(int, int), 1, 1) DEF_PairType(PairType(PetscInt, PetscInt), 1, 1)
388 
389   /* If we don't know the basic type, we treat it as a stream of chars or ints */
390   DEF_DumbType(char, 1, 1) DEF_DumbType(char, 2, 1) DEF_DumbType(char, 4, 1) DEF_DumbType(char, 1, 0) DEF_DumbType(char, 2, 0) DEF_DumbType(char, 4, 0)
391 
392     typedef int DumbInt; /* To have a different name than 'int' used above. The name is used to make routine names. */
393 DEF_DumbType(DumbInt, 1, 1) DEF_DumbType(DumbInt, 2, 1) DEF_DumbType(DumbInt, 4, 1) DEF_DumbType(DumbInt, 8, 1) DEF_DumbType(DumbInt, 1, 0) DEF_DumbType(DumbInt, 2, 0) DEF_DumbType(DumbInt, 4, 0) DEF_DumbType(DumbInt, 8, 0)
394 
395   PetscErrorCode PetscSFLinkDestroy(PetscSF sf, PetscSFLink link)
396 {
397   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
398   PetscInt       i, nreqs = (bas->nrootreqs + sf->nleafreqs) * 8;
399 
400   PetscFunctionBegin;
401   /* Destroy device-specific fields */
402   if (link->deviceinited) PetscCall((*link->Destroy)(sf, link));
403 
404   /* Destroy host related fields */
405   if (!link->isbuiltin) PetscCallMPI(MPI_Type_free(&link->unit));
406   if (!link->use_nvshmem) {
407     for (i = 0; i < nreqs; i++) { /* Persistent reqs must be freed. */
408       if (link->reqs[i] != MPI_REQUEST_NULL) PetscCallMPI(MPI_Request_free(&link->reqs[i]));
409     }
410     PetscCall(PetscFree(link->reqs));
411     for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
412       PetscCall(PetscFree(link->rootbuf_alloc[i][PETSC_MEMTYPE_HOST]));
413       PetscCall(PetscFree(link->leafbuf_alloc[i][PETSC_MEMTYPE_HOST]));
414     }
415   }
416   PetscCall(PetscFree(link));
417   PetscFunctionReturn(PETSC_SUCCESS);
418 }
419 
420 PetscErrorCode PetscSFLinkCreate(PetscSF sf, MPI_Datatype unit, PetscMemType rootmtype, const void *rootdata, PetscMemType leafmtype, const void *leafdata, MPI_Op op, PetscSFOperation sfop, PetscSFLink *mylink)
421 {
422   PetscFunctionBegin;
423   PetscCall(PetscSFSetErrorOnUnsupportedOverlap(sf, unit, rootdata, leafdata));
424 #if defined(PETSC_HAVE_NVSHMEM)
425   {
426     PetscBool use_nvshmem;
427     PetscCall(PetscSFLinkNvshmemCheck(sf, rootmtype, rootdata, leafmtype, leafdata, &use_nvshmem));
428     if (use_nvshmem) {
429       PetscCall(PetscSFLinkCreate_NVSHMEM(sf, unit, rootmtype, rootdata, leafmtype, leafdata, op, sfop, mylink));
430       PetscFunctionReturn(PETSC_SUCCESS);
431     }
432   }
433 #endif
434   PetscCall(PetscSFLinkCreate_MPI(sf, unit, rootmtype, rootdata, leafmtype, leafdata, op, sfop, mylink));
435   PetscFunctionReturn(PETSC_SUCCESS);
436 }
437 
438 PetscErrorCode PetscSFLinkGetInUse(PetscSF sf, MPI_Datatype unit, const void *rootdata, const void *leafdata, PetscCopyMode cmode, PetscSFLink *mylink)
439 {
440   PetscSFLink    link, *p;
441   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
442 
443   PetscFunctionBegin;
444   /* Look for types in cache */
445   for (p = &bas->inuse; (link = *p); p = &link->next) {
446     PetscBool match;
447     PetscCall(MPIPetsc_Type_compare(unit, link->unit, &match));
448     if (match && (rootdata == link->rootdata) && (leafdata == link->leafdata)) {
449       switch (cmode) {
450       case PETSC_OWN_POINTER:
451         *p = link->next;
452         break; /* Remove from inuse list */
453       case PETSC_USE_POINTER:
454         break;
455       default:
456         SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "invalid cmode");
457       }
458       *mylink = link;
459       PetscFunctionReturn(PETSC_SUCCESS);
460     }
461   }
462   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Could not find pack");
463 }
464 
465 PetscErrorCode PetscSFLinkReclaim(PetscSF sf, PetscSFLink *mylink)
466 {
467   PetscSF_Basic *bas  = (PetscSF_Basic *)sf->data;
468   PetscSFLink    link = *mylink;
469 
470   PetscFunctionBegin;
471   link->rootdata = NULL;
472   link->leafdata = NULL;
473   link->next     = bas->avail;
474   bas->avail     = link;
475   *mylink        = NULL;
476   PetscFunctionReturn(PETSC_SUCCESS);
477 }
478 
479 /* Error out on unsupported overlapped communications */
480 PetscErrorCode PetscSFSetErrorOnUnsupportedOverlap(PetscSF sf, MPI_Datatype unit, const void *rootdata, const void *leafdata)
481 {
482   PetscSFLink    link, *p;
483   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
484   PetscBool      match;
485 
486   PetscFunctionBegin;
487   if (PetscDefined(USE_DEBUG)) {
488     /* Look up links in use and error out if there is a match. When both rootdata and leafdata are NULL, ignore
489        the potential overlapping since this process does not participate in communication. Overlapping is harmless.
490     */
491     if (rootdata || leafdata) {
492       for (p = &bas->inuse; (link = *p); p = &link->next) {
493         PetscCall(MPIPetsc_Type_compare(unit, link->unit, &match));
494         PetscCheck(!match || rootdata != link->rootdata || leafdata != link->leafdata, PETSC_COMM_SELF, PETSC_ERR_SUP, "Overlapped PetscSF with the same rootdata(%p), leafdata(%p) and data type. Undo the overlapping to avoid the error.", rootdata, leafdata);
495       }
496     }
497   }
498   PetscFunctionReturn(PETSC_SUCCESS);
499 }
500 
501 static PetscErrorCode PetscSFLinkMemcpy_Host(PetscSFLink link, PetscMemType dstmtype, void *dst, PetscMemType srcmtype, const void *src, size_t n)
502 {
503   PetscFunctionBegin;
504   if (n) PetscCall(PetscMemcpy(dst, src, n));
505   PetscFunctionReturn(PETSC_SUCCESS);
506 }
507 
508 PetscErrorCode PetscSFLinkSetUp_Host(PetscSF sf, PetscSFLink link, MPI_Datatype unit)
509 {
510   PetscInt    nSignedChar = 0, nUnsignedChar = 0, nInt = 0, nPetscInt = 0, nPetscReal = 0;
511   PetscBool   is2Int, is2PetscInt;
512   PetscMPIInt ni, na, nd, combiner;
513 #if defined(PETSC_HAVE_COMPLEX)
514   PetscInt nPetscComplex = 0;
515 #endif
516 
517   PetscFunctionBegin;
518   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_SIGNED_CHAR, &nSignedChar));
519   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_UNSIGNED_CHAR, &nUnsignedChar));
520   /* MPI_CHAR is treated below as a dumb type that does not support reduction according to MPI standard */
521   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_INT, &nInt));
522   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_INT, &nPetscInt));
523   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_REAL, &nPetscReal));
524 #if defined(PETSC_HAVE_COMPLEX)
525   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_COMPLEX, &nPetscComplex));
526 #endif
527   PetscCall(MPIPetsc_Type_compare(unit, MPI_2INT, &is2Int));
528   PetscCall(MPIPetsc_Type_compare(unit, MPIU_2INT, &is2PetscInt));
529   /* TODO: shaell we also handle Fortran MPI_2REAL? */
530   PetscCallMPI(MPI_Type_get_envelope(unit, &ni, &na, &nd, &combiner));
531   link->isbuiltin = (combiner == MPI_COMBINER_NAMED) ? PETSC_TRUE : PETSC_FALSE; /* unit is MPI builtin */
532   link->bs        = 1;                                                           /* default */
533 
534   if (is2Int) {
535     PackInit_PairType_int_int_1_1(link);
536     link->bs        = 1;
537     link->unitbytes = 2 * sizeof(int);
538     link->isbuiltin = PETSC_TRUE; /* unit is PETSc builtin */
539     link->basicunit = MPI_2INT;
540     link->unit      = MPI_2INT;
541   } else if (is2PetscInt) { /* TODO: when is2PetscInt and nPetscInt=2, we don't know which path to take. The two paths support different ops. */
542     PackInit_PairType_PetscInt_PetscInt_1_1(link);
543     link->bs        = 1;
544     link->unitbytes = 2 * sizeof(PetscInt);
545     link->basicunit = MPIU_2INT;
546     link->isbuiltin = PETSC_TRUE; /* unit is PETSc builtin */
547     link->unit      = MPIU_2INT;
548   } else if (nPetscReal) {
549     if (nPetscReal == 8) PackInit_RealType_PetscReal_8_1(link);
550     else if (nPetscReal % 8 == 0) PackInit_RealType_PetscReal_8_0(link);
551     else if (nPetscReal == 4) PackInit_RealType_PetscReal_4_1(link);
552     else if (nPetscReal % 4 == 0) PackInit_RealType_PetscReal_4_0(link);
553     else if (nPetscReal == 2) PackInit_RealType_PetscReal_2_1(link);
554     else if (nPetscReal % 2 == 0) PackInit_RealType_PetscReal_2_0(link);
555     else if (nPetscReal == 1) PackInit_RealType_PetscReal_1_1(link);
556     else if (nPetscReal % 1 == 0) PackInit_RealType_PetscReal_1_0(link);
557     link->bs        = nPetscReal;
558     link->unitbytes = nPetscReal * sizeof(PetscReal);
559     link->basicunit = MPIU_REAL;
560     if (link->bs == 1) {
561       link->isbuiltin = PETSC_TRUE;
562       link->unit      = MPIU_REAL;
563     }
564   } else if (nPetscInt) {
565     if (nPetscInt == 8) PackInit_IntegerType_PetscInt_8_1(link);
566     else if (nPetscInt % 8 == 0) PackInit_IntegerType_PetscInt_8_0(link);
567     else if (nPetscInt == 4) PackInit_IntegerType_PetscInt_4_1(link);
568     else if (nPetscInt % 4 == 0) PackInit_IntegerType_PetscInt_4_0(link);
569     else if (nPetscInt == 2) PackInit_IntegerType_PetscInt_2_1(link);
570     else if (nPetscInt % 2 == 0) PackInit_IntegerType_PetscInt_2_0(link);
571     else if (nPetscInt == 1) PackInit_IntegerType_PetscInt_1_1(link);
572     else if (nPetscInt % 1 == 0) PackInit_IntegerType_PetscInt_1_0(link);
573     link->bs        = nPetscInt;
574     link->unitbytes = nPetscInt * sizeof(PetscInt);
575     link->basicunit = MPIU_INT;
576     if (link->bs == 1) {
577       link->isbuiltin = PETSC_TRUE;
578       link->unit      = MPIU_INT;
579     }
580 #if defined(PETSC_USE_64BIT_INDICES)
581   } else if (nInt) {
582     if (nInt == 8) PackInit_IntegerType_int_8_1(link);
583     else if (nInt % 8 == 0) PackInit_IntegerType_int_8_0(link);
584     else if (nInt == 4) PackInit_IntegerType_int_4_1(link);
585     else if (nInt % 4 == 0) PackInit_IntegerType_int_4_0(link);
586     else if (nInt == 2) PackInit_IntegerType_int_2_1(link);
587     else if (nInt % 2 == 0) PackInit_IntegerType_int_2_0(link);
588     else if (nInt == 1) PackInit_IntegerType_int_1_1(link);
589     else if (nInt % 1 == 0) PackInit_IntegerType_int_1_0(link);
590     link->bs        = nInt;
591     link->unitbytes = nInt * sizeof(int);
592     link->basicunit = MPI_INT;
593     if (link->bs == 1) {
594       link->isbuiltin = PETSC_TRUE;
595       link->unit      = MPI_INT;
596     }
597 #endif
598   } else if (nSignedChar) {
599     if (nSignedChar == 8) PackInit_IntegerType_SignedChar_8_1(link);
600     else if (nSignedChar % 8 == 0) PackInit_IntegerType_SignedChar_8_0(link);
601     else if (nSignedChar == 4) PackInit_IntegerType_SignedChar_4_1(link);
602     else if (nSignedChar % 4 == 0) PackInit_IntegerType_SignedChar_4_0(link);
603     else if (nSignedChar == 2) PackInit_IntegerType_SignedChar_2_1(link);
604     else if (nSignedChar % 2 == 0) PackInit_IntegerType_SignedChar_2_0(link);
605     else if (nSignedChar == 1) PackInit_IntegerType_SignedChar_1_1(link);
606     else if (nSignedChar % 1 == 0) PackInit_IntegerType_SignedChar_1_0(link);
607     link->bs        = nSignedChar;
608     link->unitbytes = nSignedChar * sizeof(SignedChar);
609     link->basicunit = MPI_SIGNED_CHAR;
610     if (link->bs == 1) {
611       link->isbuiltin = PETSC_TRUE;
612       link->unit      = MPI_SIGNED_CHAR;
613     }
614   } else if (nUnsignedChar) {
615     if (nUnsignedChar == 8) PackInit_IntegerType_UnsignedChar_8_1(link);
616     else if (nUnsignedChar % 8 == 0) PackInit_IntegerType_UnsignedChar_8_0(link);
617     else if (nUnsignedChar == 4) PackInit_IntegerType_UnsignedChar_4_1(link);
618     else if (nUnsignedChar % 4 == 0) PackInit_IntegerType_UnsignedChar_4_0(link);
619     else if (nUnsignedChar == 2) PackInit_IntegerType_UnsignedChar_2_1(link);
620     else if (nUnsignedChar % 2 == 0) PackInit_IntegerType_UnsignedChar_2_0(link);
621     else if (nUnsignedChar == 1) PackInit_IntegerType_UnsignedChar_1_1(link);
622     else if (nUnsignedChar % 1 == 0) PackInit_IntegerType_UnsignedChar_1_0(link);
623     link->bs        = nUnsignedChar;
624     link->unitbytes = nUnsignedChar * sizeof(UnsignedChar);
625     link->basicunit = MPI_UNSIGNED_CHAR;
626     if (link->bs == 1) {
627       link->isbuiltin = PETSC_TRUE;
628       link->unit      = MPI_UNSIGNED_CHAR;
629     }
630 #if defined(PETSC_HAVE_COMPLEX)
631   } else if (nPetscComplex) {
632     if (nPetscComplex == 8) PackInit_ComplexType_PetscComplex_8_1(link);
633     else if (nPetscComplex % 8 == 0) PackInit_ComplexType_PetscComplex_8_0(link);
634     else if (nPetscComplex == 4) PackInit_ComplexType_PetscComplex_4_1(link);
635     else if (nPetscComplex % 4 == 0) PackInit_ComplexType_PetscComplex_4_0(link);
636     else if (nPetscComplex == 2) PackInit_ComplexType_PetscComplex_2_1(link);
637     else if (nPetscComplex % 2 == 0) PackInit_ComplexType_PetscComplex_2_0(link);
638     else if (nPetscComplex == 1) PackInit_ComplexType_PetscComplex_1_1(link);
639     else if (nPetscComplex % 1 == 0) PackInit_ComplexType_PetscComplex_1_0(link);
640     link->bs        = nPetscComplex;
641     link->unitbytes = nPetscComplex * sizeof(PetscComplex);
642     link->basicunit = MPIU_COMPLEX;
643     if (link->bs == 1) {
644       link->isbuiltin = PETSC_TRUE;
645       link->unit      = MPIU_COMPLEX;
646     }
647 #endif
648   } else {
649     MPI_Aint lb, nbyte;
650     PetscCallMPI(MPI_Type_get_extent(unit, &lb, &nbyte));
651     PetscCheck(lb == 0, PETSC_COMM_SELF, PETSC_ERR_SUP, "Datatype with nonzero lower bound %ld", (long)lb);
652     if (nbyte % sizeof(int)) { /* If the type size is not multiple of int */
653       if (nbyte == 4) PackInit_DumbType_char_4_1(link);
654       else if (nbyte % 4 == 0) PackInit_DumbType_char_4_0(link);
655       else if (nbyte == 2) PackInit_DumbType_char_2_1(link);
656       else if (nbyte % 2 == 0) PackInit_DumbType_char_2_0(link);
657       else if (nbyte == 1) PackInit_DumbType_char_1_1(link);
658       else if (nbyte % 1 == 0) PackInit_DumbType_char_1_0(link);
659       link->bs        = nbyte;
660       link->unitbytes = nbyte;
661       link->basicunit = MPI_BYTE;
662     } else {
663       nInt = nbyte / sizeof(int);
664       if (nInt == 8) PackInit_DumbType_DumbInt_8_1(link);
665       else if (nInt % 8 == 0) PackInit_DumbType_DumbInt_8_0(link);
666       else if (nInt == 4) PackInit_DumbType_DumbInt_4_1(link);
667       else if (nInt % 4 == 0) PackInit_DumbType_DumbInt_4_0(link);
668       else if (nInt == 2) PackInit_DumbType_DumbInt_2_1(link);
669       else if (nInt % 2 == 0) PackInit_DumbType_DumbInt_2_0(link);
670       else if (nInt == 1) PackInit_DumbType_DumbInt_1_1(link);
671       else if (nInt % 1 == 0) PackInit_DumbType_DumbInt_1_0(link);
672       link->bs        = nInt;
673       link->unitbytes = nbyte;
674       link->basicunit = MPI_INT;
675     }
676     if (link->isbuiltin) link->unit = unit;
677   }
678 
679   if (!link->isbuiltin) PetscCallMPI(MPI_Type_dup(unit, &link->unit));
680 
681   link->Memcpy = PetscSFLinkMemcpy_Host;
682   PetscFunctionReturn(PETSC_SUCCESS);
683 }
684 
685 PetscErrorCode PetscSFLinkGetUnpackAndOp(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *))
686 {
687   PetscFunctionBegin;
688   *UnpackAndOp = NULL;
689   if (PetscMemTypeHost(mtype)) {
690     if (op == MPI_REPLACE) *UnpackAndOp = link->h_UnpackAndInsert;
691     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->h_UnpackAndAdd;
692     else if (op == MPI_PROD) *UnpackAndOp = link->h_UnpackAndMult;
693     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->h_UnpackAndMax;
694     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->h_UnpackAndMin;
695     else if (op == MPI_LAND) *UnpackAndOp = link->h_UnpackAndLAND;
696     else if (op == MPI_BAND) *UnpackAndOp = link->h_UnpackAndBAND;
697     else if (op == MPI_LOR) *UnpackAndOp = link->h_UnpackAndLOR;
698     else if (op == MPI_BOR) *UnpackAndOp = link->h_UnpackAndBOR;
699     else if (op == MPI_LXOR) *UnpackAndOp = link->h_UnpackAndLXOR;
700     else if (op == MPI_BXOR) *UnpackAndOp = link->h_UnpackAndBXOR;
701     else if (op == MPI_MAXLOC) *UnpackAndOp = link->h_UnpackAndMaxloc;
702     else if (op == MPI_MINLOC) *UnpackAndOp = link->h_UnpackAndMinloc;
703   }
704 #if defined(PETSC_HAVE_DEVICE)
705   else if (PetscMemTypeDevice(mtype) && !atomic) {
706     if (op == MPI_REPLACE) *UnpackAndOp = link->d_UnpackAndInsert;
707     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->d_UnpackAndAdd;
708     else if (op == MPI_PROD) *UnpackAndOp = link->d_UnpackAndMult;
709     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->d_UnpackAndMax;
710     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->d_UnpackAndMin;
711     else if (op == MPI_LAND) *UnpackAndOp = link->d_UnpackAndLAND;
712     else if (op == MPI_BAND) *UnpackAndOp = link->d_UnpackAndBAND;
713     else if (op == MPI_LOR) *UnpackAndOp = link->d_UnpackAndLOR;
714     else if (op == MPI_BOR) *UnpackAndOp = link->d_UnpackAndBOR;
715     else if (op == MPI_LXOR) *UnpackAndOp = link->d_UnpackAndLXOR;
716     else if (op == MPI_BXOR) *UnpackAndOp = link->d_UnpackAndBXOR;
717     else if (op == MPI_MAXLOC) *UnpackAndOp = link->d_UnpackAndMaxloc;
718     else if (op == MPI_MINLOC) *UnpackAndOp = link->d_UnpackAndMinloc;
719   } else if (PetscMemTypeDevice(mtype) && atomic) {
720     if (op == MPI_REPLACE) *UnpackAndOp = link->da_UnpackAndInsert;
721     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->da_UnpackAndAdd;
722     else if (op == MPI_PROD) *UnpackAndOp = link->da_UnpackAndMult;
723     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->da_UnpackAndMax;
724     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->da_UnpackAndMin;
725     else if (op == MPI_LAND) *UnpackAndOp = link->da_UnpackAndLAND;
726     else if (op == MPI_BAND) *UnpackAndOp = link->da_UnpackAndBAND;
727     else if (op == MPI_LOR) *UnpackAndOp = link->da_UnpackAndLOR;
728     else if (op == MPI_BOR) *UnpackAndOp = link->da_UnpackAndBOR;
729     else if (op == MPI_LXOR) *UnpackAndOp = link->da_UnpackAndLXOR;
730     else if (op == MPI_BXOR) *UnpackAndOp = link->da_UnpackAndBXOR;
731     else if (op == MPI_MAXLOC) *UnpackAndOp = link->da_UnpackAndMaxloc;
732     else if (op == MPI_MINLOC) *UnpackAndOp = link->da_UnpackAndMinloc;
733   }
734 #endif
735   PetscFunctionReturn(PETSC_SUCCESS);
736 }
737 
738 PetscErrorCode PetscSFLinkGetScatterAndOp(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**ScatterAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, PetscInt, PetscSFPackOpt, const PetscInt *, void *))
739 {
740   PetscFunctionBegin;
741   *ScatterAndOp = NULL;
742   if (PetscMemTypeHost(mtype)) {
743     if (op == MPI_REPLACE) *ScatterAndOp = link->h_ScatterAndInsert;
744     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->h_ScatterAndAdd;
745     else if (op == MPI_PROD) *ScatterAndOp = link->h_ScatterAndMult;
746     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->h_ScatterAndMax;
747     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->h_ScatterAndMin;
748     else if (op == MPI_LAND) *ScatterAndOp = link->h_ScatterAndLAND;
749     else if (op == MPI_BAND) *ScatterAndOp = link->h_ScatterAndBAND;
750     else if (op == MPI_LOR) *ScatterAndOp = link->h_ScatterAndLOR;
751     else if (op == MPI_BOR) *ScatterAndOp = link->h_ScatterAndBOR;
752     else if (op == MPI_LXOR) *ScatterAndOp = link->h_ScatterAndLXOR;
753     else if (op == MPI_BXOR) *ScatterAndOp = link->h_ScatterAndBXOR;
754     else if (op == MPI_MAXLOC) *ScatterAndOp = link->h_ScatterAndMaxloc;
755     else if (op == MPI_MINLOC) *ScatterAndOp = link->h_ScatterAndMinloc;
756   }
757 #if defined(PETSC_HAVE_DEVICE)
758   else if (PetscMemTypeDevice(mtype) && !atomic) {
759     if (op == MPI_REPLACE) *ScatterAndOp = link->d_ScatterAndInsert;
760     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->d_ScatterAndAdd;
761     else if (op == MPI_PROD) *ScatterAndOp = link->d_ScatterAndMult;
762     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->d_ScatterAndMax;
763     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->d_ScatterAndMin;
764     else if (op == MPI_LAND) *ScatterAndOp = link->d_ScatterAndLAND;
765     else if (op == MPI_BAND) *ScatterAndOp = link->d_ScatterAndBAND;
766     else if (op == MPI_LOR) *ScatterAndOp = link->d_ScatterAndLOR;
767     else if (op == MPI_BOR) *ScatterAndOp = link->d_ScatterAndBOR;
768     else if (op == MPI_LXOR) *ScatterAndOp = link->d_ScatterAndLXOR;
769     else if (op == MPI_BXOR) *ScatterAndOp = link->d_ScatterAndBXOR;
770     else if (op == MPI_MAXLOC) *ScatterAndOp = link->d_ScatterAndMaxloc;
771     else if (op == MPI_MINLOC) *ScatterAndOp = link->d_ScatterAndMinloc;
772   } else if (PetscMemTypeDevice(mtype) && atomic) {
773     if (op == MPI_REPLACE) *ScatterAndOp = link->da_ScatterAndInsert;
774     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->da_ScatterAndAdd;
775     else if (op == MPI_PROD) *ScatterAndOp = link->da_ScatterAndMult;
776     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->da_ScatterAndMax;
777     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->da_ScatterAndMin;
778     else if (op == MPI_LAND) *ScatterAndOp = link->da_ScatterAndLAND;
779     else if (op == MPI_BAND) *ScatterAndOp = link->da_ScatterAndBAND;
780     else if (op == MPI_LOR) *ScatterAndOp = link->da_ScatterAndLOR;
781     else if (op == MPI_BOR) *ScatterAndOp = link->da_ScatterAndBOR;
782     else if (op == MPI_LXOR) *ScatterAndOp = link->da_ScatterAndLXOR;
783     else if (op == MPI_BXOR) *ScatterAndOp = link->da_ScatterAndBXOR;
784     else if (op == MPI_MAXLOC) *ScatterAndOp = link->da_ScatterAndMaxloc;
785     else if (op == MPI_MINLOC) *ScatterAndOp = link->da_ScatterAndMinloc;
786   }
787 #endif
788   PetscFunctionReturn(PETSC_SUCCESS);
789 }
790 
791 PetscErrorCode PetscSFLinkGetFetchAndOp(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**FetchAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, void *))
792 {
793   PetscFunctionBegin;
794   *FetchAndOp = NULL;
795   PetscCheck(op == MPI_SUM || op == MPIU_SUM, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for MPI_Op in FetchAndOp");
796   if (PetscMemTypeHost(mtype)) *FetchAndOp = link->h_FetchAndAdd;
797 #if defined(PETSC_HAVE_DEVICE)
798   else if (PetscMemTypeDevice(mtype) && !atomic) *FetchAndOp = link->d_FetchAndAdd;
799   else if (PetscMemTypeDevice(mtype) && atomic) *FetchAndOp = link->da_FetchAndAdd;
800 #endif
801   PetscFunctionReturn(PETSC_SUCCESS);
802 }
803 
804 PetscErrorCode PetscSFLinkGetFetchAndOpLocal(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**FetchAndOpLocal)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *))
805 {
806   PetscFunctionBegin;
807   *FetchAndOpLocal = NULL;
808   PetscCheck(op == MPI_SUM || op == MPIU_SUM, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for MPI_Op in FetchAndOp");
809   if (PetscMemTypeHost(mtype)) *FetchAndOpLocal = link->h_FetchAndAddLocal;
810 #if defined(PETSC_HAVE_DEVICE)
811   else if (PetscMemTypeDevice(mtype) && !atomic) *FetchAndOpLocal = link->d_FetchAndAddLocal;
812   else if (PetscMemTypeDevice(mtype) && atomic) *FetchAndOpLocal = link->da_FetchAndAddLocal;
813 #endif
814   PetscFunctionReturn(PETSC_SUCCESS);
815 }
816 
817 static inline PetscErrorCode PetscSFLinkLogFlopsAfterUnpackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, MPI_Op op)
818 {
819   PetscLogDouble flops;
820   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
821 
822   PetscFunctionBegin;
823   if (op != MPI_REPLACE && link->basicunit == MPIU_SCALAR) { /* op is a reduction on PetscScalars */
824     flops = bas->rootbuflen[scope] * link->bs;               /* # of roots in buffer x # of scalars in unit */
825 #if defined(PETSC_HAVE_DEVICE)
826     if (PetscMemTypeDevice(link->rootmtype)) PetscCall(PetscLogGpuFlops(flops));
827     else
828 #endif
829       PetscCall(PetscLogFlops(flops));
830   }
831   PetscFunctionReturn(PETSC_SUCCESS);
832 }
833 
834 static inline PetscErrorCode PetscSFLinkLogFlopsAfterUnpackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, MPI_Op op)
835 {
836   PetscLogDouble flops;
837 
838   PetscFunctionBegin;
839   if (op != MPI_REPLACE && link->basicunit == MPIU_SCALAR) { /* op is a reduction on PetscScalars */
840     flops = sf->leafbuflen[scope] * link->bs;                /* # of roots in buffer x # of scalars in unit */
841 #if defined(PETSC_HAVE_DEVICE)
842     if (PetscMemTypeDevice(link->leafmtype)) PetscCall(PetscLogGpuFlops(flops));
843     else
844 #endif
845       PetscCall(PetscLogFlops(flops));
846   }
847   PetscFunctionReturn(PETSC_SUCCESS);
848 }
849 
850 /* When SF could not find a proper UnpackAndOp() from link, it falls back to MPI_Reduce_local.
851   Input Parameters:
852   +sf      - The StarForest
853   .link    - The link
854   .count   - Number of entries to unpack
855   .start   - The first index, significant when indices=NULL
856   .indices - Indices of entries in <data>. If NULL, it means indices are contiguous and the first is given in <start>
857   .buf     - A contiguous buffer to unpack from
858   -op      - Operation after unpack
859 
860   Output Parameters:
861   .data    - The data to unpack to
862 */
863 static inline PetscErrorCode PetscSFLinkUnpackDataWithMPIReduceLocal(PetscSF sf, PetscSFLink link, PetscInt count, PetscInt start, const PetscInt *indices, void *data, const void *buf, MPI_Op op)
864 {
865   PetscFunctionBegin;
866 #if defined(PETSC_HAVE_MPI_REDUCE_LOCAL)
867   {
868     PetscInt i;
869     if (indices) {
870       /* Note we use link->unit instead of link->basicunit. When op can be mapped to MPI_SUM etc, it operates on
871          basic units of a root/leaf element-wisely. Otherwise, it is meant to operate on a whole root/leaf.
872       */
873       for (i = 0; i < count; i++) PetscCallMPI(MPI_Reduce_local((const char *)buf + i * link->unitbytes, (char *)data + indices[i] * link->unitbytes, 1, link->unit, op));
874     } else {
875       PetscCallMPI(MPIU_Reduce_local(buf, (char *)data + start * link->unitbytes, count, link->unit, op));
876     }
877   }
878   PetscFunctionReturn(PETSC_SUCCESS);
879 #else
880   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No unpacking reduction operation for this MPI_Op");
881 #endif
882 }
883 
884 static inline PetscErrorCode PetscSFLinkScatterDataWithMPIReduceLocal(PetscSF sf, PetscSFLink link, PetscInt count, PetscInt srcStart, const PetscInt *srcIdx, const void *src, PetscInt dstStart, const PetscInt *dstIdx, void *dst, MPI_Op op)
885 {
886   PetscFunctionBegin;
887 #if defined(PETSC_HAVE_MPI_REDUCE_LOCAL)
888   {
889     PetscInt i, disp;
890     if (!srcIdx) {
891       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, dstStart, dstIdx, dst, (const char *)src + srcStart * link->unitbytes, op));
892     } else {
893       for (i = 0; i < count; i++) {
894         disp = dstIdx ? dstIdx[i] : dstStart + i;
895         PetscCallMPI(MPIU_Reduce_local((const char *)src + srcIdx[i] * link->unitbytes, (char *)dst + disp * link->unitbytes, 1, link->unit, op));
896       }
897     }
898   }
899   PetscFunctionReturn(PETSC_SUCCESS);
900 #else
901   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No unpacking reduction operation for this MPI_Op");
902 #endif
903 }
904 
905 /*=============================================================================
906               Pack/Unpack/Fetch/Scatter routines
907  ============================================================================*/
908 
909 /* Pack rootdata to rootbuf
910   Input Parameters:
911   + sf       - The SF this packing works on.
912   . link     - It gives the memtype of the roots and also provides root buffer.
913   . scope    - PETSCSF_LOCAL or PETSCSF_REMOTE. Note SF has the ability to do local and remote communications separately.
914   - rootdata - Where to read the roots.
915 
916   Notes:
917   When rootdata can be directly used as root buffer, the routine is almost a no-op. After the call, root data is
918   in a place where the underlying MPI is ready to access (use_gpu_aware_mpi or not)
919  */
920 static PetscErrorCode PetscSFLinkPackRootData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *rootdata)
921 {
922   const PetscInt *rootindices = NULL;
923   PetscInt        count, start;
924   PetscErrorCode (*Pack)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
925   PetscMemType   rootmtype                                                                                        = link->rootmtype;
926   PetscSFPackOpt opt                                                                                              = NULL;
927 
928   PetscFunctionBegin;
929   if (!link->rootdirect[scope]) { /* If rootdata works directly as rootbuf, skip packing */
930     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, scope, &count, &start, &opt, &rootindices));
931     PetscCall(PetscSFLinkGetPack(link, rootmtype, &Pack));
932     PetscCall((*Pack)(link, count, start, opt, rootindices, rootdata, link->rootbuf[scope][rootmtype]));
933   }
934   PetscFunctionReturn(PETSC_SUCCESS);
935 }
936 
937 /* Pack leafdata to leafbuf */
938 static PetscErrorCode PetscSFLinkPackLeafData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *leafdata)
939 {
940   const PetscInt *leafindices = NULL;
941   PetscInt        count, start;
942   PetscErrorCode (*Pack)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
943   PetscMemType   leafmtype                                                                                        = link->leafmtype;
944   PetscSFPackOpt opt                                                                                              = NULL;
945 
946   PetscFunctionBegin;
947   if (!link->leafdirect[scope]) { /* If leafdata works directly as rootbuf, skip packing */
948     PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, scope, &count, &start, &opt, &leafindices));
949     PetscCall(PetscSFLinkGetPack(link, leafmtype, &Pack));
950     PetscCall((*Pack)(link, count, start, opt, leafindices, leafdata, link->leafbuf[scope][leafmtype]));
951   }
952   PetscFunctionReturn(PETSC_SUCCESS);
953 }
954 
955 /* Pack rootdata to rootbuf, which are in the same memory space */
956 PetscErrorCode PetscSFLinkPackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *rootdata)
957 {
958   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
959 
960   PetscFunctionBegin;
961   if (scope == PETSCSF_REMOTE) { /* Sync the device if rootdata is not on petsc default stream */
962     if (PetscMemTypeDevice(link->rootmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
963     if (link->PrePack) PetscCall((*link->PrePack)(sf, link, PETSCSF_ROOT2LEAF)); /* Used by SF nvshmem */
964   }
965   PetscCall(PetscLogEventBegin(PETSCSF_Pack, sf, 0, 0, 0));
966   if (bas->rootbuflen[scope]) PetscCall(PetscSFLinkPackRootData_Private(sf, link, scope, rootdata));
967   PetscCall(PetscLogEventEnd(PETSCSF_Pack, sf, 0, 0, 0));
968   PetscFunctionReturn(PETSC_SUCCESS);
969 }
970 /* Pack leafdata to leafbuf, which are in the same memory space */
971 PetscErrorCode PetscSFLinkPackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *leafdata)
972 {
973   PetscFunctionBegin;
974   if (scope == PETSCSF_REMOTE) {
975     if (PetscMemTypeDevice(link->leafmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
976     if (link->PrePack) PetscCall((*link->PrePack)(sf, link, PETSCSF_LEAF2ROOT)); /* Used by SF nvshmem */
977   }
978   PetscCall(PetscLogEventBegin(PETSCSF_Pack, sf, 0, 0, 0));
979   if (sf->leafbuflen[scope]) PetscCall(PetscSFLinkPackLeafData_Private(sf, link, scope, leafdata));
980   PetscCall(PetscLogEventEnd(PETSCSF_Pack, sf, 0, 0, 0));
981   PetscFunctionReturn(PETSC_SUCCESS);
982 }
983 
984 static PetscErrorCode PetscSFLinkUnpackRootData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *rootdata, MPI_Op op)
985 {
986   const PetscInt *rootindices = NULL;
987   PetscInt        count, start;
988   PetscSF_Basic  *bas                                                                                                    = (PetscSF_Basic *)sf->data;
989   PetscErrorCode (*UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *) = NULL;
990   PetscMemType   rootmtype                                                                                               = link->rootmtype;
991   PetscSFPackOpt opt                                                                                                     = NULL;
992 
993   PetscFunctionBegin;
994   if (!link->rootdirect[scope]) { /* If rootdata works directly as rootbuf, skip unpacking */
995     PetscCall(PetscSFLinkGetUnpackAndOp(link, rootmtype, op, bas->rootdups[scope], &UnpackAndOp));
996     if (UnpackAndOp) {
997       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, scope, &count, &start, &opt, &rootindices));
998       PetscCall((*UnpackAndOp)(link, count, start, opt, rootindices, rootdata, link->rootbuf[scope][rootmtype]));
999     } else {
1000       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, scope, &count, &start, &opt, &rootindices));
1001       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, start, rootindices, rootdata, link->rootbuf[scope][rootmtype], op));
1002     }
1003   }
1004   PetscCall(PetscSFLinkLogFlopsAfterUnpackRootData(sf, link, scope, op));
1005   PetscFunctionReturn(PETSC_SUCCESS);
1006 }
1007 
1008 static PetscErrorCode PetscSFLinkUnpackLeafData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *leafdata, MPI_Op op)
1009 {
1010   const PetscInt *leafindices = NULL;
1011   PetscInt        count, start;
1012   PetscErrorCode (*UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *) = NULL;
1013   PetscMemType   leafmtype                                                                                               = link->leafmtype;
1014   PetscSFPackOpt opt                                                                                                     = NULL;
1015 
1016   PetscFunctionBegin;
1017   if (!link->leafdirect[scope]) { /* If leafdata works directly as rootbuf, skip unpacking */
1018     PetscCall(PetscSFLinkGetUnpackAndOp(link, leafmtype, op, sf->leafdups[scope], &UnpackAndOp));
1019     if (UnpackAndOp) {
1020       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, scope, &count, &start, &opt, &leafindices));
1021       PetscCall((*UnpackAndOp)(link, count, start, opt, leafindices, leafdata, link->leafbuf[scope][leafmtype]));
1022     } else {
1023       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, scope, &count, &start, &opt, &leafindices));
1024       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, start, leafindices, leafdata, link->leafbuf[scope][leafmtype], op));
1025     }
1026   }
1027   PetscCall(PetscSFLinkLogFlopsAfterUnpackLeafData(sf, link, scope, op));
1028   PetscFunctionReturn(PETSC_SUCCESS);
1029 }
1030 /* Unpack rootbuf to rootdata, which are in the same memory space */
1031 PetscErrorCode PetscSFLinkUnpackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *rootdata, MPI_Op op)
1032 {
1033   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1034 
1035   PetscFunctionBegin;
1036   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0));
1037   if (bas->rootbuflen[scope]) PetscCall(PetscSFLinkUnpackRootData_Private(sf, link, scope, rootdata, op));
1038   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1039   if (scope == PETSCSF_REMOTE) {
1040     if (link->PostUnpack) PetscCall((*link->PostUnpack)(sf, link, PETSCSF_LEAF2ROOT)); /* Used by SF nvshmem */
1041     if (PetscMemTypeDevice(link->rootmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
1042   }
1043   PetscFunctionReturn(PETSC_SUCCESS);
1044 }
1045 
1046 /* Unpack leafbuf to leafdata for remote (common case) or local (rare case when rootmtype != leafmtype) */
1047 PetscErrorCode PetscSFLinkUnpackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *leafdata, MPI_Op op)
1048 {
1049   PetscFunctionBegin;
1050   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0));
1051   if (sf->leafbuflen[scope]) PetscCall(PetscSFLinkUnpackLeafData_Private(sf, link, scope, leafdata, op));
1052   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1053   if (scope == PETSCSF_REMOTE) {
1054     if (link->PostUnpack) PetscCall((*link->PostUnpack)(sf, link, PETSCSF_ROOT2LEAF)); /* Used by SF nvshmem */
1055     if (PetscMemTypeDevice(link->leafmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
1056   }
1057   PetscFunctionReturn(PETSC_SUCCESS);
1058 }
1059 
1060 /* FetchAndOp rootdata with rootbuf, it is a kind of Unpack on rootdata, except it also updates rootbuf */
1061 PetscErrorCode PetscSFLinkFetchAndOpRemote(PetscSF sf, PetscSFLink link, void *rootdata, MPI_Op op)
1062 {
1063   const PetscInt *rootindices = NULL;
1064   PetscInt        count, start;
1065   PetscSF_Basic  *bas                                                                                             = (PetscSF_Basic *)sf->data;
1066   PetscErrorCode (*FetchAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, void *) = NULL;
1067   PetscMemType   rootmtype                                                                                        = link->rootmtype;
1068   PetscSFPackOpt opt                                                                                              = NULL;
1069 
1070   PetscFunctionBegin;
1071   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0));
1072   if (bas->rootbuflen[PETSCSF_REMOTE]) {
1073     /* Do FetchAndOp on rootdata with rootbuf */
1074     PetscCall(PetscSFLinkGetFetchAndOp(link, rootmtype, op, bas->rootdups[PETSCSF_REMOTE], &FetchAndOp));
1075     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_REMOTE, &count, &start, &opt, &rootindices));
1076     PetscCall((*FetchAndOp)(link, count, start, opt, rootindices, rootdata, link->rootbuf[PETSCSF_REMOTE][rootmtype]));
1077   }
1078   PetscCall(PetscSFLinkLogFlopsAfterUnpackRootData(sf, link, PETSCSF_REMOTE, op));
1079   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1080   PetscFunctionReturn(PETSC_SUCCESS);
1081 }
1082 
1083 PetscErrorCode PetscSFLinkScatterLocal(PetscSF sf, PetscSFLink link, PetscSFDirection direction, void *rootdata, void *leafdata, MPI_Op op)
1084 {
1085   const PetscInt *rootindices = NULL, *leafindices = NULL;
1086   PetscInt        count, rootstart, leafstart;
1087   PetscSF_Basic  *bas                                                                                                                                                 = (PetscSF_Basic *)sf->data;
1088   PetscErrorCode (*ScatterAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, PetscInt, PetscSFPackOpt, const PetscInt *, void *) = NULL;
1089   PetscMemType   rootmtype = link->rootmtype, leafmtype = link->leafmtype, srcmtype, dstmtype;
1090   PetscSFPackOpt leafopt = NULL, rootopt = NULL;
1091   PetscInt       buflen = sf->leafbuflen[PETSCSF_LOCAL];
1092   char          *srcbuf = NULL, *dstbuf = NULL;
1093   PetscBool      dstdups;
1094 
1095   PetscFunctionBegin;
1096   if (!buflen) PetscFunctionReturn(PETSC_SUCCESS);
1097   if (rootmtype != leafmtype) { /* The cross memory space local scatter is done by pack, copy and unpack */
1098     if (direction == PETSCSF_ROOT2LEAF) {
1099       PetscCall(PetscSFLinkPackRootData(sf, link, PETSCSF_LOCAL, rootdata));
1100       srcmtype = rootmtype;
1101       srcbuf   = link->rootbuf[PETSCSF_LOCAL][rootmtype];
1102       dstmtype = leafmtype;
1103       dstbuf   = link->leafbuf[PETSCSF_LOCAL][leafmtype];
1104     } else {
1105       PetscCall(PetscSFLinkPackLeafData(sf, link, PETSCSF_LOCAL, leafdata));
1106       srcmtype = leafmtype;
1107       srcbuf   = link->leafbuf[PETSCSF_LOCAL][leafmtype];
1108       dstmtype = rootmtype;
1109       dstbuf   = link->rootbuf[PETSCSF_LOCAL][rootmtype];
1110     }
1111     PetscCall((*link->Memcpy)(link, dstmtype, dstbuf, srcmtype, srcbuf, buflen * link->unitbytes));
1112     /* If above is a device to host copy, we have to sync the stream before accessing the buffer on host */
1113     if (PetscMemTypeHost(dstmtype)) PetscCall((*link->SyncStream)(link));
1114     if (direction == PETSCSF_ROOT2LEAF) {
1115       PetscCall(PetscSFLinkUnpackLeafData(sf, link, PETSCSF_LOCAL, leafdata, op));
1116     } else {
1117       PetscCall(PetscSFLinkUnpackRootData(sf, link, PETSCSF_LOCAL, rootdata, op));
1118     }
1119   } else {
1120     dstdups  = (direction == PETSCSF_ROOT2LEAF) ? sf->leafdups[PETSCSF_LOCAL] : bas->rootdups[PETSCSF_LOCAL];
1121     dstmtype = (direction == PETSCSF_ROOT2LEAF) ? link->leafmtype : link->rootmtype;
1122     PetscCall(PetscSFLinkGetScatterAndOp(link, dstmtype, op, dstdups, &ScatterAndOp));
1123     if (ScatterAndOp) {
1124       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1125       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1126       if (direction == PETSCSF_ROOT2LEAF) {
1127         PetscCall((*ScatterAndOp)(link, count, rootstart, rootopt, rootindices, rootdata, leafstart, leafopt, leafindices, leafdata));
1128       } else {
1129         PetscCall((*ScatterAndOp)(link, count, leafstart, leafopt, leafindices, leafdata, rootstart, rootopt, rootindices, rootdata));
1130       }
1131     } else {
1132       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1133       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1134       if (direction == PETSCSF_ROOT2LEAF) {
1135         PetscCall(PetscSFLinkScatterDataWithMPIReduceLocal(sf, link, count, rootstart, rootindices, rootdata, leafstart, leafindices, leafdata, op));
1136       } else {
1137         PetscCall(PetscSFLinkScatterDataWithMPIReduceLocal(sf, link, count, leafstart, leafindices, leafdata, rootstart, rootindices, rootdata, op));
1138       }
1139     }
1140   }
1141   PetscFunctionReturn(PETSC_SUCCESS);
1142 }
1143 
1144 /* Fetch rootdata to leafdata and leafupdate locally */
1145 PetscErrorCode PetscSFLinkFetchAndOpLocal(PetscSF sf, PetscSFLink link, void *rootdata, const void *leafdata, void *leafupdate, MPI_Op op)
1146 {
1147   const PetscInt *rootindices = NULL, *leafindices = NULL;
1148   PetscInt        count, rootstart, leafstart;
1149   PetscSF_Basic  *bas                                                                                                                                                            = (PetscSF_Basic *)sf->data;
1150   PetscErrorCode (*FetchAndOpLocal)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
1151   const PetscMemType rootmtype = link->rootmtype, leafmtype = link->leafmtype;
1152   PetscSFPackOpt     leafopt = NULL, rootopt = NULL;
1153 
1154   PetscFunctionBegin;
1155   if (!bas->rootbuflen[PETSCSF_LOCAL]) PetscFunctionReturn(PETSC_SUCCESS);
1156   if (rootmtype != leafmtype) {
1157     /* The local communication has to go through pack and unpack */
1158     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Doing PetscSFFetchAndOp with rootdata and leafdata on opposite side of CPU and GPU");
1159   } else {
1160     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1161     PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1162     PetscCall(PetscSFLinkGetFetchAndOpLocal(link, rootmtype, op, bas->rootdups[PETSCSF_LOCAL], &FetchAndOpLocal));
1163     PetscCall((*FetchAndOpLocal)(link, count, rootstart, rootopt, rootindices, rootdata, leafstart, leafopt, leafindices, leafdata, leafupdate));
1164   }
1165   PetscFunctionReturn(PETSC_SUCCESS);
1166 }
1167 
1168 /*
1169   Create per-rank pack/unpack optimizations based on indices patterns
1170 
1171    Input Parameters:
1172   +  n       - Number of destination ranks
1173   .  offset  - [n+1] For the i-th rank, its associated indices are idx[offset[i], offset[i+1]). offset[0] needs not to be 0.
1174   -  idx     - [*]   Array storing indices
1175 
1176    Output Parameters:
1177   +  opt     - Pack optimizations. NULL if no optimizations.
1178 */
1179 static PetscErrorCode PetscSFCreatePackOpt(PetscInt n, const PetscInt *offset, const PetscInt *idx, PetscSFPackOpt *out)
1180 {
1181   PetscInt       r, p, start, i, j, k, dx, dy, dz, dydz, m, X, Y;
1182   PetscBool      optimizable = PETSC_TRUE;
1183   PetscSFPackOpt opt;
1184 
1185   PetscFunctionBegin;
1186   PetscCall(PetscMalloc1(1, &opt));
1187   PetscCall(PetscMalloc1(7 * n + 2, &opt->array));
1188   opt->n = opt->array[0] = n;
1189   opt->offset            = opt->array + 1;
1190   opt->start             = opt->array + n + 2;
1191   opt->dx                = opt->array + 2 * n + 2;
1192   opt->dy                = opt->array + 3 * n + 2;
1193   opt->dz                = opt->array + 4 * n + 2;
1194   opt->X                 = opt->array + 5 * n + 2;
1195   opt->Y                 = opt->array + 6 * n + 2;
1196 
1197   for (r = 0; r < n; r++) {            /* For each destination rank */
1198     m     = offset[r + 1] - offset[r]; /* Total number of indices for this rank. We want to see if m can be factored into dx*dy*dz */
1199     p     = offset[r];
1200     start = idx[p]; /* First index for this rank */
1201     p++;
1202 
1203     /* Search in X dimension */
1204     for (dx = 1; dx < m; dx++, p++) {
1205       if (start + dx != idx[p]) break;
1206     }
1207 
1208     dydz = m / dx;
1209     X    = dydz > 1 ? (idx[p] - start) : dx;
1210     /* Not optimizable if m is not a multiple of dx, or some unrecognized pattern is found */
1211     if (m % dx || X <= 0) {
1212       optimizable = PETSC_FALSE;
1213       goto finish;
1214     }
1215     for (dy = 1; dy < dydz; dy++) { /* Search in Y dimension */
1216       for (i = 0; i < dx; i++, p++) {
1217         if (start + X * dy + i != idx[p]) {
1218           if (i) {
1219             optimizable = PETSC_FALSE;
1220             goto finish;
1221           } /* The pattern is violated in the middle of an x-walk */
1222           else
1223             goto Z_dimension;
1224         }
1225       }
1226     }
1227 
1228   Z_dimension:
1229     dz = m / (dx * dy);
1230     Y  = dz > 1 ? (idx[p] - start) / X : dy;
1231     /* Not optimizable if m is not a multiple of dx*dy, or some unrecognized pattern is found */
1232     if (m % (dx * dy) || Y <= 0) {
1233       optimizable = PETSC_FALSE;
1234       goto finish;
1235     }
1236     for (k = 1; k < dz; k++) { /* Go through Z dimension to see if remaining indices follow the pattern */
1237       for (j = 0; j < dy; j++) {
1238         for (i = 0; i < dx; i++, p++) {
1239           if (start + X * Y * k + X * j + i != idx[p]) {
1240             optimizable = PETSC_FALSE;
1241             goto finish;
1242           }
1243         }
1244       }
1245     }
1246     opt->start[r] = start;
1247     opt->dx[r]    = dx;
1248     opt->dy[r]    = dy;
1249     opt->dz[r]    = dz;
1250     opt->X[r]     = X;
1251     opt->Y[r]     = Y;
1252   }
1253 
1254 finish:
1255   /* If not optimizable, free arrays to save memory */
1256   if (!n || !optimizable) {
1257     PetscCall(PetscFree(opt->array));
1258     PetscCall(PetscFree(opt));
1259     *out = NULL;
1260   } else {
1261     opt->offset[0] = 0;
1262     for (r = 0; r < n; r++) opt->offset[r + 1] = opt->offset[r] + opt->dx[r] * opt->dy[r] * opt->dz[r];
1263     *out = opt;
1264   }
1265   PetscFunctionReturn(PETSC_SUCCESS);
1266 }
1267 
1268 static inline PetscErrorCode PetscSFDestroyPackOpt(PetscSF sf, PetscMemType mtype, PetscSFPackOpt *out)
1269 {
1270   PetscSFPackOpt opt = *out;
1271 
1272   PetscFunctionBegin;
1273   if (opt) {
1274     PetscCall(PetscSFFree(sf, mtype, opt->array));
1275     PetscCall(PetscFree(opt));
1276     *out = NULL;
1277   }
1278   PetscFunctionReturn(PETSC_SUCCESS);
1279 }
1280 
1281 PetscErrorCode PetscSFSetUpPackFields(PetscSF sf)
1282 {
1283   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1284   PetscInt       i, j;
1285 
1286   PetscFunctionBegin;
1287   /* [0] for PETSCSF_LOCAL and [1] for PETSCSF_REMOTE in the following */
1288   for (i = 0; i < 2; i++) { /* Set defaults */
1289     sf->leafstart[i]   = 0;
1290     sf->leafcontig[i]  = PETSC_TRUE;
1291     sf->leafdups[i]    = PETSC_FALSE;
1292     bas->rootstart[i]  = 0;
1293     bas->rootcontig[i] = PETSC_TRUE;
1294     bas->rootdups[i]   = PETSC_FALSE;
1295   }
1296 
1297   sf->leafbuflen[0] = sf->roffset[sf->ndranks];
1298   sf->leafbuflen[1] = sf->roffset[sf->nranks] - sf->roffset[sf->ndranks];
1299 
1300   if (sf->leafbuflen[0]) sf->leafstart[0] = sf->rmine[0];
1301   if (sf->leafbuflen[1]) sf->leafstart[1] = sf->rmine[sf->roffset[sf->ndranks]];
1302 
1303   /* Are leaf indices for self and remote contiguous? If yes, it is best for pack/unpack */
1304   for (i = 0; i < sf->roffset[sf->ndranks]; i++) { /* self */
1305     if (sf->rmine[i] != sf->leafstart[0] + i) {
1306       sf->leafcontig[0] = PETSC_FALSE;
1307       break;
1308     }
1309   }
1310   for (i = sf->roffset[sf->ndranks], j = 0; i < sf->roffset[sf->nranks]; i++, j++) { /* remote */
1311     if (sf->rmine[i] != sf->leafstart[1] + j) {
1312       sf->leafcontig[1] = PETSC_FALSE;
1313       break;
1314     }
1315   }
1316 
1317   /* If not, see if we can have per-rank optimizations by doing index analysis */
1318   if (!sf->leafcontig[0]) PetscCall(PetscSFCreatePackOpt(sf->ndranks, sf->roffset, sf->rmine, &sf->leafpackopt[0]));
1319   if (!sf->leafcontig[1]) PetscCall(PetscSFCreatePackOpt(sf->nranks - sf->ndranks, sf->roffset + sf->ndranks, sf->rmine, &sf->leafpackopt[1]));
1320 
1321   /* Are root indices for self and remote contiguous? */
1322   bas->rootbuflen[0] = bas->ioffset[bas->ndiranks];
1323   bas->rootbuflen[1] = bas->ioffset[bas->niranks] - bas->ioffset[bas->ndiranks];
1324 
1325   if (bas->rootbuflen[0]) bas->rootstart[0] = bas->irootloc[0];
1326   if (bas->rootbuflen[1]) bas->rootstart[1] = bas->irootloc[bas->ioffset[bas->ndiranks]];
1327 
1328   for (i = 0; i < bas->ioffset[bas->ndiranks]; i++) {
1329     if (bas->irootloc[i] != bas->rootstart[0] + i) {
1330       bas->rootcontig[0] = PETSC_FALSE;
1331       break;
1332     }
1333   }
1334   for (i = bas->ioffset[bas->ndiranks], j = 0; i < bas->ioffset[bas->niranks]; i++, j++) {
1335     if (bas->irootloc[i] != bas->rootstart[1] + j) {
1336       bas->rootcontig[1] = PETSC_FALSE;
1337       break;
1338     }
1339   }
1340 
1341   if (!bas->rootcontig[0]) PetscCall(PetscSFCreatePackOpt(bas->ndiranks, bas->ioffset, bas->irootloc, &bas->rootpackopt[0]));
1342   if (!bas->rootcontig[1]) PetscCall(PetscSFCreatePackOpt(bas->niranks - bas->ndiranks, bas->ioffset + bas->ndiranks, bas->irootloc, &bas->rootpackopt[1]));
1343 
1344   /* Check dups in indices so that CUDA unpacking kernels can use cheaper regular instructions instead of atomics when they know there are no data race chances */
1345   if (PetscDefined(HAVE_DEVICE)) {
1346     PetscBool ismulti = (sf->multi == sf) ? PETSC_TRUE : PETSC_FALSE;
1347     if (!sf->leafcontig[0] && !ismulti) PetscCall(PetscCheckDupsInt(sf->leafbuflen[0], sf->rmine, &sf->leafdups[0]));
1348     if (!sf->leafcontig[1] && !ismulti) PetscCall(PetscCheckDupsInt(sf->leafbuflen[1], sf->rmine + sf->roffset[sf->ndranks], &sf->leafdups[1]));
1349     if (!bas->rootcontig[0] && !ismulti) PetscCall(PetscCheckDupsInt(bas->rootbuflen[0], bas->irootloc, &bas->rootdups[0]));
1350     if (!bas->rootcontig[1] && !ismulti) PetscCall(PetscCheckDupsInt(bas->rootbuflen[1], bas->irootloc + bas->ioffset[bas->ndiranks], &bas->rootdups[1]));
1351   }
1352   PetscFunctionReturn(PETSC_SUCCESS);
1353 }
1354 
1355 PetscErrorCode PetscSFResetPackFields(PetscSF sf)
1356 {
1357   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1358   PetscInt       i;
1359 
1360   PetscFunctionBegin;
1361   for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
1362     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_HOST, &sf->leafpackopt[i]));
1363     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_HOST, &bas->rootpackopt[i]));
1364 #if defined(PETSC_HAVE_DEVICE)
1365     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_DEVICE, &sf->leafpackopt_d[i]));
1366     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_DEVICE, &bas->rootpackopt_d[i]));
1367 #endif
1368   }
1369   PetscFunctionReturn(PETSC_SUCCESS);
1370 }
1371