xref: /petsc/src/vec/is/sf/impls/basic/sfpack.c (revision 174dc0c8cee294b82b85e4dd3b331b29396264fc)
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   MPIU_Count  ni, na, nc, nd;
513   PetscMPIInt combiner;
514 #if defined(PETSC_HAVE_COMPLEX)
515   PetscInt nPetscComplex = 0;
516 #endif
517 
518   PetscFunctionBegin;
519   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_SIGNED_CHAR, &nSignedChar));
520   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_UNSIGNED_CHAR, &nUnsignedChar));
521   /* MPI_CHAR is treated below as a dumb type that does not support reduction according to MPI standard */
522   PetscCall(MPIPetsc_Type_compare_contig(unit, MPI_INT, &nInt));
523   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_INT, &nPetscInt));
524   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_REAL, &nPetscReal));
525 #if defined(PETSC_HAVE_COMPLEX)
526   PetscCall(MPIPetsc_Type_compare_contig(unit, MPIU_COMPLEX, &nPetscComplex));
527 #endif
528   PetscCall(MPIPetsc_Type_compare(unit, MPI_2INT, &is2Int));
529   PetscCall(MPIPetsc_Type_compare(unit, MPIU_2INT, &is2PetscInt));
530   /* TODO: should we also handle Fortran MPI_2REAL? */
531   PetscCallMPI(MPIPetsc_Type_get_envelope(unit, &ni, &na, &nc, &nd, &combiner));
532   link->isbuiltin = (combiner == MPI_COMBINER_NAMED) ? PETSC_TRUE : PETSC_FALSE; /* unit is MPI builtin */
533   link->bs        = 1;                                                           /* default */
534 
535   if (is2Int) {
536     PackInit_PairType_int_int_1_1(link);
537     link->bs        = 1;
538     link->unitbytes = 2 * sizeof(int);
539     link->isbuiltin = PETSC_TRUE; /* unit is PETSc builtin */
540     link->basicunit = MPI_2INT;
541     link->unit      = MPI_2INT;
542   } else if (is2PetscInt) { /* TODO: when is2PetscInt and nPetscInt=2, we don't know which path to take. The two paths support different ops. */
543     PackInit_PairType_PetscInt_PetscInt_1_1(link);
544     link->bs        = 1;
545     link->unitbytes = 2 * sizeof(PetscInt);
546     link->basicunit = MPIU_2INT;
547     link->isbuiltin = PETSC_TRUE; /* unit is PETSc builtin */
548     link->unit      = MPIU_2INT;
549   } else if (nPetscReal) {
550     if (nPetscReal == 8) PackInit_RealType_PetscReal_8_1(link);
551     else if (nPetscReal % 8 == 0) PackInit_RealType_PetscReal_8_0(link);
552     else if (nPetscReal == 4) PackInit_RealType_PetscReal_4_1(link);
553     else if (nPetscReal % 4 == 0) PackInit_RealType_PetscReal_4_0(link);
554     else if (nPetscReal == 2) PackInit_RealType_PetscReal_2_1(link);
555     else if (nPetscReal % 2 == 0) PackInit_RealType_PetscReal_2_0(link);
556     else if (nPetscReal == 1) PackInit_RealType_PetscReal_1_1(link);
557     else if (nPetscReal % 1 == 0) PackInit_RealType_PetscReal_1_0(link);
558     link->bs        = nPetscReal;
559     link->unitbytes = nPetscReal * sizeof(PetscReal);
560     link->basicunit = MPIU_REAL;
561     if (link->bs == 1) {
562       link->isbuiltin = PETSC_TRUE;
563       link->unit      = MPIU_REAL;
564     }
565   } else if (nPetscInt) {
566     if (nPetscInt == 8) PackInit_IntegerType_PetscInt_8_1(link);
567     else if (nPetscInt % 8 == 0) PackInit_IntegerType_PetscInt_8_0(link);
568     else if (nPetscInt == 4) PackInit_IntegerType_PetscInt_4_1(link);
569     else if (nPetscInt % 4 == 0) PackInit_IntegerType_PetscInt_4_0(link);
570     else if (nPetscInt == 2) PackInit_IntegerType_PetscInt_2_1(link);
571     else if (nPetscInt % 2 == 0) PackInit_IntegerType_PetscInt_2_0(link);
572     else if (nPetscInt == 1) PackInit_IntegerType_PetscInt_1_1(link);
573     else if (nPetscInt % 1 == 0) PackInit_IntegerType_PetscInt_1_0(link);
574     link->bs        = nPetscInt;
575     link->unitbytes = nPetscInt * sizeof(PetscInt);
576     link->basicunit = MPIU_INT;
577     if (link->bs == 1) {
578       link->isbuiltin = PETSC_TRUE;
579       link->unit      = MPIU_INT;
580     }
581 #if defined(PETSC_USE_64BIT_INDICES)
582   } else if (nInt) {
583     if (nInt == 8) PackInit_IntegerType_int_8_1(link);
584     else if (nInt % 8 == 0) PackInit_IntegerType_int_8_0(link);
585     else if (nInt == 4) PackInit_IntegerType_int_4_1(link);
586     else if (nInt % 4 == 0) PackInit_IntegerType_int_4_0(link);
587     else if (nInt == 2) PackInit_IntegerType_int_2_1(link);
588     else if (nInt % 2 == 0) PackInit_IntegerType_int_2_0(link);
589     else if (nInt == 1) PackInit_IntegerType_int_1_1(link);
590     else if (nInt % 1 == 0) PackInit_IntegerType_int_1_0(link);
591     link->bs        = nInt;
592     link->unitbytes = nInt * sizeof(int);
593     link->basicunit = MPI_INT;
594     if (link->bs == 1) {
595       link->isbuiltin = PETSC_TRUE;
596       link->unit      = MPI_INT;
597     }
598 #endif
599   } else if (nSignedChar) {
600     if (nSignedChar == 8) PackInit_IntegerType_SignedChar_8_1(link);
601     else if (nSignedChar % 8 == 0) PackInit_IntegerType_SignedChar_8_0(link);
602     else if (nSignedChar == 4) PackInit_IntegerType_SignedChar_4_1(link);
603     else if (nSignedChar % 4 == 0) PackInit_IntegerType_SignedChar_4_0(link);
604     else if (nSignedChar == 2) PackInit_IntegerType_SignedChar_2_1(link);
605     else if (nSignedChar % 2 == 0) PackInit_IntegerType_SignedChar_2_0(link);
606     else if (nSignedChar == 1) PackInit_IntegerType_SignedChar_1_1(link);
607     else if (nSignedChar % 1 == 0) PackInit_IntegerType_SignedChar_1_0(link);
608     link->bs        = nSignedChar;
609     link->unitbytes = nSignedChar * sizeof(SignedChar);
610     link->basicunit = MPI_SIGNED_CHAR;
611     if (link->bs == 1) {
612       link->isbuiltin = PETSC_TRUE;
613       link->unit      = MPI_SIGNED_CHAR;
614     }
615   } else if (nUnsignedChar) {
616     if (nUnsignedChar == 8) PackInit_IntegerType_UnsignedChar_8_1(link);
617     else if (nUnsignedChar % 8 == 0) PackInit_IntegerType_UnsignedChar_8_0(link);
618     else if (nUnsignedChar == 4) PackInit_IntegerType_UnsignedChar_4_1(link);
619     else if (nUnsignedChar % 4 == 0) PackInit_IntegerType_UnsignedChar_4_0(link);
620     else if (nUnsignedChar == 2) PackInit_IntegerType_UnsignedChar_2_1(link);
621     else if (nUnsignedChar % 2 == 0) PackInit_IntegerType_UnsignedChar_2_0(link);
622     else if (nUnsignedChar == 1) PackInit_IntegerType_UnsignedChar_1_1(link);
623     else if (nUnsignedChar % 1 == 0) PackInit_IntegerType_UnsignedChar_1_0(link);
624     link->bs        = nUnsignedChar;
625     link->unitbytes = nUnsignedChar * sizeof(UnsignedChar);
626     link->basicunit = MPI_UNSIGNED_CHAR;
627     if (link->bs == 1) {
628       link->isbuiltin = PETSC_TRUE;
629       link->unit      = MPI_UNSIGNED_CHAR;
630     }
631 #if defined(PETSC_HAVE_COMPLEX)
632   } else if (nPetscComplex) {
633     if (nPetscComplex == 8) PackInit_ComplexType_PetscComplex_8_1(link);
634     else if (nPetscComplex % 8 == 0) PackInit_ComplexType_PetscComplex_8_0(link);
635     else if (nPetscComplex == 4) PackInit_ComplexType_PetscComplex_4_1(link);
636     else if (nPetscComplex % 4 == 0) PackInit_ComplexType_PetscComplex_4_0(link);
637     else if (nPetscComplex == 2) PackInit_ComplexType_PetscComplex_2_1(link);
638     else if (nPetscComplex % 2 == 0) PackInit_ComplexType_PetscComplex_2_0(link);
639     else if (nPetscComplex == 1) PackInit_ComplexType_PetscComplex_1_1(link);
640     else if (nPetscComplex % 1 == 0) PackInit_ComplexType_PetscComplex_1_0(link);
641     link->bs        = nPetscComplex;
642     link->unitbytes = nPetscComplex * sizeof(PetscComplex);
643     link->basicunit = MPIU_COMPLEX;
644     if (link->bs == 1) {
645       link->isbuiltin = PETSC_TRUE;
646       link->unit      = MPIU_COMPLEX;
647     }
648 #endif
649   } else {
650     MPI_Aint lb, nbyte;
651 
652     PetscCallMPI(MPI_Type_get_extent(unit, &lb, &nbyte));
653     PetscCheck(lb == 0, PETSC_COMM_SELF, PETSC_ERR_SUP, "Datatype with nonzero lower bound %ld", (long)lb);
654     if (nbyte % sizeof(int)) { /* If the type size is not multiple of int */
655       if (nbyte == 4) PackInit_DumbType_char_4_1(link);
656       else if (nbyte % 4 == 0) PackInit_DumbType_char_4_0(link);
657       else if (nbyte == 2) PackInit_DumbType_char_2_1(link);
658       else if (nbyte % 2 == 0) PackInit_DumbType_char_2_0(link);
659       else if (nbyte == 1) PackInit_DumbType_char_1_1(link);
660       else if (nbyte % 1 == 0) PackInit_DumbType_char_1_0(link);
661       PetscCall(PetscIntCast(nbyte, &link->bs));
662       link->unitbytes = nbyte;
663       link->basicunit = MPI_BYTE;
664     } else {
665       PetscCall(PetscIntCast(nbyte / sizeof(int), &nInt));
666       if (nInt == 8) PackInit_DumbType_DumbInt_8_1(link);
667       else if (nInt % 8 == 0) PackInit_DumbType_DumbInt_8_0(link);
668       else if (nInt == 4) PackInit_DumbType_DumbInt_4_1(link);
669       else if (nInt % 4 == 0) PackInit_DumbType_DumbInt_4_0(link);
670       else if (nInt == 2) PackInit_DumbType_DumbInt_2_1(link);
671       else if (nInt % 2 == 0) PackInit_DumbType_DumbInt_2_0(link);
672       else if (nInt == 1) PackInit_DumbType_DumbInt_1_1(link);
673       else if (nInt % 1 == 0) PackInit_DumbType_DumbInt_1_0(link);
674       link->bs        = nInt;
675       link->unitbytes = nbyte;
676       link->basicunit = MPI_INT;
677     }
678     if (link->isbuiltin) link->unit = unit;
679   }
680 
681   if (!link->isbuiltin) PetscCallMPI(MPI_Type_dup(unit, &link->unit));
682 
683   link->Memcpy = PetscSFLinkMemcpy_Host;
684   PetscFunctionReturn(PETSC_SUCCESS);
685 }
686 
687 PetscErrorCode PetscSFLinkGetUnpackAndOp(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *))
688 {
689   PetscFunctionBegin;
690   *UnpackAndOp = NULL;
691   if (PetscMemTypeHost(mtype)) {
692     if (op == MPI_REPLACE) *UnpackAndOp = link->h_UnpackAndInsert;
693     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->h_UnpackAndAdd;
694     else if (op == MPI_PROD) *UnpackAndOp = link->h_UnpackAndMult;
695     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->h_UnpackAndMax;
696     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->h_UnpackAndMin;
697     else if (op == MPI_LAND) *UnpackAndOp = link->h_UnpackAndLAND;
698     else if (op == MPI_BAND) *UnpackAndOp = link->h_UnpackAndBAND;
699     else if (op == MPI_LOR) *UnpackAndOp = link->h_UnpackAndLOR;
700     else if (op == MPI_BOR) *UnpackAndOp = link->h_UnpackAndBOR;
701     else if (op == MPI_LXOR) *UnpackAndOp = link->h_UnpackAndLXOR;
702     else if (op == MPI_BXOR) *UnpackAndOp = link->h_UnpackAndBXOR;
703     else if (op == MPI_MAXLOC) *UnpackAndOp = link->h_UnpackAndMaxloc;
704     else if (op == MPI_MINLOC) *UnpackAndOp = link->h_UnpackAndMinloc;
705   }
706 #if defined(PETSC_HAVE_DEVICE)
707   else if (PetscMemTypeDevice(mtype) && !atomic) {
708     if (op == MPI_REPLACE) *UnpackAndOp = link->d_UnpackAndInsert;
709     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->d_UnpackAndAdd;
710     else if (op == MPI_PROD) *UnpackAndOp = link->d_UnpackAndMult;
711     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->d_UnpackAndMax;
712     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->d_UnpackAndMin;
713     else if (op == MPI_LAND) *UnpackAndOp = link->d_UnpackAndLAND;
714     else if (op == MPI_BAND) *UnpackAndOp = link->d_UnpackAndBAND;
715     else if (op == MPI_LOR) *UnpackAndOp = link->d_UnpackAndLOR;
716     else if (op == MPI_BOR) *UnpackAndOp = link->d_UnpackAndBOR;
717     else if (op == MPI_LXOR) *UnpackAndOp = link->d_UnpackAndLXOR;
718     else if (op == MPI_BXOR) *UnpackAndOp = link->d_UnpackAndBXOR;
719     else if (op == MPI_MAXLOC) *UnpackAndOp = link->d_UnpackAndMaxloc;
720     else if (op == MPI_MINLOC) *UnpackAndOp = link->d_UnpackAndMinloc;
721   } else if (PetscMemTypeDevice(mtype) && atomic) {
722     if (op == MPI_REPLACE) *UnpackAndOp = link->da_UnpackAndInsert;
723     else if (op == MPI_SUM || op == MPIU_SUM) *UnpackAndOp = link->da_UnpackAndAdd;
724     else if (op == MPI_PROD) *UnpackAndOp = link->da_UnpackAndMult;
725     else if (op == MPI_MAX || op == MPIU_MAX) *UnpackAndOp = link->da_UnpackAndMax;
726     else if (op == MPI_MIN || op == MPIU_MIN) *UnpackAndOp = link->da_UnpackAndMin;
727     else if (op == MPI_LAND) *UnpackAndOp = link->da_UnpackAndLAND;
728     else if (op == MPI_BAND) *UnpackAndOp = link->da_UnpackAndBAND;
729     else if (op == MPI_LOR) *UnpackAndOp = link->da_UnpackAndLOR;
730     else if (op == MPI_BOR) *UnpackAndOp = link->da_UnpackAndBOR;
731     else if (op == MPI_LXOR) *UnpackAndOp = link->da_UnpackAndLXOR;
732     else if (op == MPI_BXOR) *UnpackAndOp = link->da_UnpackAndBXOR;
733     else if (op == MPI_MAXLOC) *UnpackAndOp = link->da_UnpackAndMaxloc;
734     else if (op == MPI_MINLOC) *UnpackAndOp = link->da_UnpackAndMinloc;
735   }
736 #endif
737   PetscFunctionReturn(PETSC_SUCCESS);
738 }
739 
740 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 *))
741 {
742   PetscFunctionBegin;
743   *ScatterAndOp = NULL;
744   if (PetscMemTypeHost(mtype)) {
745     if (op == MPI_REPLACE) *ScatterAndOp = link->h_ScatterAndInsert;
746     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->h_ScatterAndAdd;
747     else if (op == MPI_PROD) *ScatterAndOp = link->h_ScatterAndMult;
748     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->h_ScatterAndMax;
749     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->h_ScatterAndMin;
750     else if (op == MPI_LAND) *ScatterAndOp = link->h_ScatterAndLAND;
751     else if (op == MPI_BAND) *ScatterAndOp = link->h_ScatterAndBAND;
752     else if (op == MPI_LOR) *ScatterAndOp = link->h_ScatterAndLOR;
753     else if (op == MPI_BOR) *ScatterAndOp = link->h_ScatterAndBOR;
754     else if (op == MPI_LXOR) *ScatterAndOp = link->h_ScatterAndLXOR;
755     else if (op == MPI_BXOR) *ScatterAndOp = link->h_ScatterAndBXOR;
756     else if (op == MPI_MAXLOC) *ScatterAndOp = link->h_ScatterAndMaxloc;
757     else if (op == MPI_MINLOC) *ScatterAndOp = link->h_ScatterAndMinloc;
758   }
759 #if defined(PETSC_HAVE_DEVICE)
760   else if (PetscMemTypeDevice(mtype) && !atomic) {
761     if (op == MPI_REPLACE) *ScatterAndOp = link->d_ScatterAndInsert;
762     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->d_ScatterAndAdd;
763     else if (op == MPI_PROD) *ScatterAndOp = link->d_ScatterAndMult;
764     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->d_ScatterAndMax;
765     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->d_ScatterAndMin;
766     else if (op == MPI_LAND) *ScatterAndOp = link->d_ScatterAndLAND;
767     else if (op == MPI_BAND) *ScatterAndOp = link->d_ScatterAndBAND;
768     else if (op == MPI_LOR) *ScatterAndOp = link->d_ScatterAndLOR;
769     else if (op == MPI_BOR) *ScatterAndOp = link->d_ScatterAndBOR;
770     else if (op == MPI_LXOR) *ScatterAndOp = link->d_ScatterAndLXOR;
771     else if (op == MPI_BXOR) *ScatterAndOp = link->d_ScatterAndBXOR;
772     else if (op == MPI_MAXLOC) *ScatterAndOp = link->d_ScatterAndMaxloc;
773     else if (op == MPI_MINLOC) *ScatterAndOp = link->d_ScatterAndMinloc;
774   } else if (PetscMemTypeDevice(mtype) && atomic) {
775     if (op == MPI_REPLACE) *ScatterAndOp = link->da_ScatterAndInsert;
776     else if (op == MPI_SUM || op == MPIU_SUM) *ScatterAndOp = link->da_ScatterAndAdd;
777     else if (op == MPI_PROD) *ScatterAndOp = link->da_ScatterAndMult;
778     else if (op == MPI_MAX || op == MPIU_MAX) *ScatterAndOp = link->da_ScatterAndMax;
779     else if (op == MPI_MIN || op == MPIU_MIN) *ScatterAndOp = link->da_ScatterAndMin;
780     else if (op == MPI_LAND) *ScatterAndOp = link->da_ScatterAndLAND;
781     else if (op == MPI_BAND) *ScatterAndOp = link->da_ScatterAndBAND;
782     else if (op == MPI_LOR) *ScatterAndOp = link->da_ScatterAndLOR;
783     else if (op == MPI_BOR) *ScatterAndOp = link->da_ScatterAndBOR;
784     else if (op == MPI_LXOR) *ScatterAndOp = link->da_ScatterAndLXOR;
785     else if (op == MPI_BXOR) *ScatterAndOp = link->da_ScatterAndBXOR;
786     else if (op == MPI_MAXLOC) *ScatterAndOp = link->da_ScatterAndMaxloc;
787     else if (op == MPI_MINLOC) *ScatterAndOp = link->da_ScatterAndMinloc;
788   }
789 #endif
790   PetscFunctionReturn(PETSC_SUCCESS);
791 }
792 
793 PetscErrorCode PetscSFLinkGetFetchAndOp(PetscSFLink link, PetscMemType mtype, MPI_Op op, PetscBool atomic, PetscErrorCode (**FetchAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, void *))
794 {
795   PetscFunctionBegin;
796   *FetchAndOp = NULL;
797   PetscCheck(op == MPI_SUM || op == MPIU_SUM, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for MPI_Op in FetchAndOp");
798   if (PetscMemTypeHost(mtype)) *FetchAndOp = link->h_FetchAndAdd;
799 #if defined(PETSC_HAVE_DEVICE)
800   else if (PetscMemTypeDevice(mtype) && !atomic) *FetchAndOp = link->d_FetchAndAdd;
801   else if (PetscMemTypeDevice(mtype) && atomic) *FetchAndOp = link->da_FetchAndAdd;
802 #endif
803   PetscFunctionReturn(PETSC_SUCCESS);
804 }
805 
806 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 *))
807 {
808   PetscFunctionBegin;
809   *FetchAndOpLocal = NULL;
810   PetscCheck(op == MPI_SUM || op == MPIU_SUM, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for MPI_Op in FetchAndOp");
811   if (PetscMemTypeHost(mtype)) *FetchAndOpLocal = link->h_FetchAndAddLocal;
812 #if defined(PETSC_HAVE_DEVICE)
813   else if (PetscMemTypeDevice(mtype) && !atomic) *FetchAndOpLocal = link->d_FetchAndAddLocal;
814   else if (PetscMemTypeDevice(mtype) && atomic) *FetchAndOpLocal = link->da_FetchAndAddLocal;
815 #endif
816   PetscFunctionReturn(PETSC_SUCCESS);
817 }
818 
819 static inline PetscErrorCode PetscSFLinkLogFlopsAfterUnpackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, MPI_Op op)
820 {
821   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
822 
823   PetscFunctionBegin;
824   if (op != MPI_REPLACE && link->basicunit == MPIU_SCALAR) { /* op is a reduction on PetscScalars */
825 #if defined(PETSC_HAVE_DEVICE)
826     if (PetscMemTypeDevice(link->rootmtype)) PetscCall(PetscLogGpuFlops(bas->rootbuflen[scope] * link->bs));
827     else
828 #endif
829       PetscCall(PetscLogFlops(bas->rootbuflen[scope] * link->bs)); /* # of roots in buffer x # of scalars in unit */
830   }
831   PetscFunctionReturn(PETSC_SUCCESS);
832 }
833 
834 static inline PetscErrorCode PetscSFLinkLogFlopsAfterUnpackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, MPI_Op op)
835 {
836   PetscFunctionBegin;
837   if (op != MPI_REPLACE && link->basicunit == MPIU_SCALAR) { /* op is a reduction on PetscScalars */
838 #if defined(PETSC_HAVE_DEVICE)
839     if (PetscMemTypeDevice(link->leafmtype)) PetscCall(PetscLogGpuFlops(sf->leafbuflen[scope] * link->bs)); /* # of roots in buffer x # of scalars in unit */
840     else
841 #endif
842       PetscCall(PetscLogFlops(sf->leafbuflen[scope] * link->bs));
843   }
844   PetscFunctionReturn(PETSC_SUCCESS);
845 }
846 
847 /* When SF could not find a proper UnpackAndOp() from link, it falls back to MPI_Reduce_local.
848   Input Parameters:
849   +sf      - The StarForest
850   .link    - The link
851   .count   - Number of entries to unpack
852   .start   - The first index, significant when indices=NULL
853   .indices - Indices of entries in <data>. If NULL, it means indices are contiguous and the first is given in <start>
854   .buf     - A contiguous buffer to unpack from
855   -op      - Operation after unpack
856 
857   Output Parameters:
858   .data    - The data to unpack to
859 */
860 static inline PetscErrorCode PetscSFLinkUnpackDataWithMPIReduceLocal(PetscSF sf, PetscSFLink link, PetscInt count, PetscInt start, const PetscInt *indices, void *data, const void *buf, MPI_Op op)
861 {
862   PetscFunctionBegin;
863 #if defined(PETSC_HAVE_MPI_REDUCE_LOCAL)
864   {
865     PetscInt i;
866     if (indices) {
867       /* Note we use link->unit instead of link->basicunit. When op can be mapped to MPI_SUM etc, it operates on
868          basic units of a root/leaf element-wisely. Otherwise, it is meant to operate on a whole root/leaf.
869       */
870       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));
871     } else {
872       PetscCheck(op != MPI_REPLACE, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MPI_REPLACE is not an allowed op in MPI_Reduce_local() per MPI standard");
873       PetscCallMPI(MPIU_Reduce_local(buf, (char *)data + start * link->unitbytes, count, link->unit, op));
874     }
875   }
876   PetscFunctionReturn(PETSC_SUCCESS);
877 #else
878   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No unpacking reduction operation for this MPI_Op");
879 #endif
880 }
881 
882 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)
883 {
884   PetscFunctionBegin;
885 #if defined(PETSC_HAVE_MPI_REDUCE_LOCAL)
886   {
887     PetscInt i, disp;
888     if (!srcIdx) {
889       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, dstStart, dstIdx, dst, (const char *)src + srcStart * link->unitbytes, op));
890     } else {
891       PetscCheck(op != MPI_REPLACE, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MPI_REPLACE is not an allowed op in MPI_Reduce_local() per MPI standard");
892       for (i = 0; i < count; i++) {
893         disp = dstIdx ? dstIdx[i] : dstStart + i;
894         PetscCallMPI(MPIU_Reduce_local((const char *)src + srcIdx[i] * link->unitbytes, (char *)dst + disp * link->unitbytes, 1, link->unit, op));
895       }
896     }
897   }
898   PetscFunctionReturn(PETSC_SUCCESS);
899 #else
900   SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No unpacking reduction operation for this MPI_Op");
901 #endif
902 }
903 
904 /*=============================================================================
905               Pack/Unpack/Fetch/Scatter routines
906  ============================================================================*/
907 
908 /* Pack rootdata to rootbuf
909   Input Parameters:
910   + sf       - The SF this packing works on.
911   . link     - It gives the memtype of the roots and also provides root buffer.
912   . scope    - PETSCSF_LOCAL or PETSCSF_REMOTE. Note SF has the ability to do local and remote communications separately.
913   - rootdata - Where to read the roots.
914 
915   Notes:
916   When rootdata can be directly used as root buffer, the routine is almost a no-op. After the call, root data is
917   in a place where the underlying MPI is ready to access (use_gpu_aware_mpi or not)
918  */
919 static PetscErrorCode PetscSFLinkPackRootData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *rootdata)
920 {
921   const PetscInt *rootindices = NULL;
922   PetscInt        count, start;
923   PetscMemType    rootmtype                                                                                       = link->rootmtype;
924   PetscSFPackOpt  opt                                                                                             = NULL;
925   PetscErrorCode (*Pack)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
926 
927   PetscFunctionBegin;
928   if (!link->rootdirect[scope]) { /* If rootdata works directly as rootbuf, skip packing */
929     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, scope, &count, &start, &opt, &rootindices));
930     PetscCall(PetscSFLinkGetPack(link, rootmtype, &Pack));
931     PetscCall((*Pack)(link, count, start, opt, rootindices, rootdata, link->rootbuf[scope][rootmtype]));
932   }
933   PetscFunctionReturn(PETSC_SUCCESS);
934 }
935 
936 /* Pack leafdata to leafbuf */
937 static PetscErrorCode PetscSFLinkPackLeafData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *leafdata)
938 {
939   const PetscInt *leafindices = NULL;
940   PetscInt        count, start;
941   PetscMemType    leafmtype                                                                                       = link->leafmtype;
942   PetscSFPackOpt  opt                                                                                             = NULL;
943   PetscErrorCode (*Pack)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
944 
945   PetscFunctionBegin;
946   if (!link->leafdirect[scope]) { /* If leafdata works directly as rootbuf, skip packing */
947     PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, scope, &count, &start, &opt, &leafindices));
948     PetscCall(PetscSFLinkGetPack(link, leafmtype, &Pack));
949     PetscCall((*Pack)(link, count, start, opt, leafindices, leafdata, link->leafbuf[scope][leafmtype]));
950   }
951   PetscFunctionReturn(PETSC_SUCCESS);
952 }
953 
954 /* Pack rootdata to rootbuf, which are in the same memory space */
955 PetscErrorCode PetscSFLinkPackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *rootdata)
956 {
957   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
958 
959   PetscFunctionBegin;
960   if (scope == PETSCSF_REMOTE) { /* Sync the device if rootdata is not on PETSc default stream */
961     if (PetscMemTypeDevice(link->rootmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
962     if (link->PrePack) PetscCall((*link->PrePack)(sf, link, PETSCSF_ROOT2LEAF)); /* Used by SF nvshmem */
963   }
964   PetscCall(PetscLogEventBegin(PETSCSF_Pack, sf, 0, 0, 0));
965   if (bas->rootbuflen[scope]) PetscCall(PetscSFLinkPackRootData_Private(sf, link, scope, rootdata));
966   PetscCall(PetscLogEventEnd(PETSCSF_Pack, sf, 0, 0, 0));
967   PetscFunctionReturn(PETSC_SUCCESS);
968 }
969 /* Pack leafdata to leafbuf, which are in the same memory space */
970 PetscErrorCode PetscSFLinkPackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, const void *leafdata)
971 {
972   PetscFunctionBegin;
973   if (scope == PETSCSF_REMOTE) {
974     if (PetscMemTypeDevice(link->leafmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
975     if (link->PrePack) PetscCall((*link->PrePack)(sf, link, PETSCSF_LEAF2ROOT)); /* Used by SF nvshmem */
976   }
977   PetscCall(PetscLogEventBegin(PETSCSF_Pack, sf, 0, 0, 0));
978   if (sf->leafbuflen[scope]) PetscCall(PetscSFLinkPackLeafData_Private(sf, link, scope, leafdata));
979   PetscCall(PetscLogEventEnd(PETSCSF_Pack, sf, 0, 0, 0));
980   PetscFunctionReturn(PETSC_SUCCESS);
981 }
982 
983 static PetscErrorCode PetscSFLinkUnpackRootData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *rootdata, MPI_Op op)
984 {
985   const PetscInt *rootindices = NULL;
986   PetscInt        count, start;
987   PetscSF_Basic  *bas                                                                                                    = (PetscSF_Basic *)sf->data;
988   PetscMemType    rootmtype                                                                                              = link->rootmtype;
989   PetscSFPackOpt  opt                                                                                                    = NULL;
990   PetscErrorCode (*UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *) = NULL;
991 
992   PetscFunctionBegin;
993   if (!link->rootdirect[scope]) { /* If rootdata works directly as rootbuf, skip unpacking */
994     PetscCall(PetscSFLinkGetUnpackAndOp(link, rootmtype, op, bas->rootdups[scope], &UnpackAndOp));
995     if (UnpackAndOp) {
996       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, scope, &count, &start, &opt, &rootindices));
997       PetscCall((*UnpackAndOp)(link, count, start, opt, rootindices, rootdata, link->rootbuf[scope][rootmtype]));
998     } else {
999       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, scope, &count, &start, &opt, &rootindices));
1000       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, start, rootindices, rootdata, link->rootbuf[scope][rootmtype], op));
1001     }
1002   }
1003   PetscCall(PetscSFLinkLogFlopsAfterUnpackRootData(sf, link, scope, op));
1004   PetscFunctionReturn(PETSC_SUCCESS);
1005 }
1006 
1007 static PetscErrorCode PetscSFLinkUnpackLeafData_Private(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *leafdata, MPI_Op op)
1008 {
1009   const PetscInt *leafindices = NULL;
1010   PetscInt        count, start;
1011   PetscErrorCode (*UnpackAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, const void *) = NULL;
1012   PetscMemType   leafmtype                                                                                               = link->leafmtype;
1013   PetscSFPackOpt opt                                                                                                     = NULL;
1014 
1015   PetscFunctionBegin;
1016   if (!link->leafdirect[scope]) { /* If leafdata works directly as rootbuf, skip unpacking */
1017     PetscCall(PetscSFLinkGetUnpackAndOp(link, leafmtype, op, sf->leafdups[scope], &UnpackAndOp));
1018     if (UnpackAndOp) {
1019       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, scope, &count, &start, &opt, &leafindices));
1020       PetscCall((*UnpackAndOp)(link, count, start, opt, leafindices, leafdata, link->leafbuf[scope][leafmtype]));
1021     } else {
1022       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, scope, &count, &start, &opt, &leafindices));
1023       PetscCall(PetscSFLinkUnpackDataWithMPIReduceLocal(sf, link, count, start, leafindices, leafdata, link->leafbuf[scope][leafmtype], op));
1024     }
1025   }
1026   PetscCall(PetscSFLinkLogFlopsAfterUnpackLeafData(sf, link, scope, op));
1027   PetscFunctionReturn(PETSC_SUCCESS);
1028 }
1029 /* Unpack rootbuf to rootdata, which are in the same memory space */
1030 PetscErrorCode PetscSFLinkUnpackRootData(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *rootdata, MPI_Op op)
1031 {
1032   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1033 
1034   PetscFunctionBegin;
1035   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0)); // call it even no data is unpacked so that -log_sync can be done collectively
1036   if (bas->rootbuflen[scope] && !link->rootdirect[scope]) PetscCall(PetscSFLinkUnpackRootData_Private(sf, link, scope, rootdata, op));
1037   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1038   if (scope == PETSCSF_REMOTE) {
1039     if (link->PostUnpack) PetscCall((*link->PostUnpack)(sf, link, PETSCSF_LEAF2ROOT)); /* Used by SF nvshmem */
1040     if (PetscMemTypeDevice(link->rootmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
1041   }
1042   PetscFunctionReturn(PETSC_SUCCESS);
1043 }
1044 
1045 /* Unpack leafbuf to leafdata for remote (common case) or local (rare case when rootmtype != leafmtype) */
1046 PetscErrorCode PetscSFLinkUnpackLeafData(PetscSF sf, PetscSFLink link, PetscSFScope scope, void *leafdata, MPI_Op op)
1047 {
1048   PetscFunctionBegin;
1049   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0));
1050   if (sf->leafbuflen[scope] && !link->leafdirect[scope]) PetscCall(PetscSFLinkUnpackLeafData_Private(sf, link, scope, leafdata, op));
1051   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1052   if (scope == PETSCSF_REMOTE) {
1053     if (link->PostUnpack) PetscCall((*link->PostUnpack)(sf, link, PETSCSF_ROOT2LEAF)); /* Used by SF nvshmem */
1054     if (PetscMemTypeDevice(link->leafmtype) && link->SyncDevice && sf->unknown_input_stream) PetscCall((*link->SyncDevice)(link));
1055   }
1056   PetscFunctionReturn(PETSC_SUCCESS);
1057 }
1058 
1059 /* FetchAndOp rootdata with rootbuf, it is a kind of Unpack on rootdata, except it also updates rootbuf */
1060 PetscErrorCode PetscSFLinkFetchAndOpRemote(PetscSF sf, PetscSFLink link, void *rootdata, MPI_Op op)
1061 {
1062   const PetscInt *rootindices = NULL;
1063   PetscInt        count, start;
1064   PetscSF_Basic  *bas                                                                                             = (PetscSF_Basic *)sf->data;
1065   PetscErrorCode (*FetchAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, void *) = NULL;
1066   PetscMemType   rootmtype                                                                                        = link->rootmtype;
1067   PetscSFPackOpt opt                                                                                              = NULL;
1068 
1069   PetscFunctionBegin;
1070   PetscCall(PetscLogEventBegin(PETSCSF_Unpack, sf, 0, 0, 0));
1071   if (bas->rootbuflen[PETSCSF_REMOTE]) {
1072     /* Do FetchAndOp on rootdata with rootbuf */
1073     PetscCall(PetscSFLinkGetFetchAndOp(link, rootmtype, op, bas->rootdups[PETSCSF_REMOTE], &FetchAndOp));
1074     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_REMOTE, &count, &start, &opt, &rootindices));
1075     PetscCall((*FetchAndOp)(link, count, start, opt, rootindices, rootdata, link->rootbuf[PETSCSF_REMOTE][rootmtype]));
1076   }
1077   PetscCall(PetscSFLinkLogFlopsAfterUnpackRootData(sf, link, PETSCSF_REMOTE, op));
1078   PetscCall(PetscLogEventEnd(PETSCSF_Unpack, sf, 0, 0, 0));
1079   PetscFunctionReturn(PETSC_SUCCESS);
1080 }
1081 
1082 PetscErrorCode PetscSFLinkScatterLocal(PetscSF sf, PetscSFLink link, PetscSFDirection direction, void *rootdata, void *leafdata, MPI_Op op)
1083 {
1084   const PetscInt *rootindices = NULL, *leafindices = NULL;
1085   PetscInt        count, rootstart, leafstart;
1086   PetscSF_Basic  *bas       = (PetscSF_Basic *)sf->data;
1087   PetscMemType    rootmtype = link->rootmtype, leafmtype = link->leafmtype, srcmtype, dstmtype;
1088   PetscSFPackOpt  leafopt = NULL, rootopt = NULL;
1089   PetscInt        buflen = sf->leafbuflen[PETSCSF_LOCAL];
1090   char           *srcbuf = NULL, *dstbuf = NULL;
1091   PetscBool       dstdups;
1092   PetscErrorCode (*ScatterAndOp)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, PetscInt, PetscSFPackOpt, const PetscInt *, void *) = NULL;
1093 
1094   PetscFunctionBegin;
1095   if (!buflen) PetscFunctionReturn(PETSC_SUCCESS);
1096   if (rootmtype != leafmtype) { /* The cross memory space local scatter is done by pack, copy and unpack */
1097     if (direction == PETSCSF_ROOT2LEAF) {
1098       PetscCall(PetscSFLinkPackRootData(sf, link, PETSCSF_LOCAL, rootdata));
1099       srcmtype = rootmtype;
1100       srcbuf   = link->rootbuf[PETSCSF_LOCAL][rootmtype];
1101       dstmtype = leafmtype;
1102       dstbuf   = link->leafbuf[PETSCSF_LOCAL][leafmtype];
1103     } else {
1104       PetscCall(PetscSFLinkPackLeafData(sf, link, PETSCSF_LOCAL, leafdata));
1105       srcmtype = leafmtype;
1106       srcbuf   = link->leafbuf[PETSCSF_LOCAL][leafmtype];
1107       dstmtype = rootmtype;
1108       dstbuf   = link->rootbuf[PETSCSF_LOCAL][rootmtype];
1109     }
1110     PetscCall((*link->Memcpy)(link, dstmtype, dstbuf, srcmtype, srcbuf, buflen * link->unitbytes));
1111     /* If above is a device to host copy, we have to sync the stream before accessing the buffer on host */
1112     if (PetscMemTypeHost(dstmtype)) PetscCall((*link->SyncStream)(link));
1113     if (direction == PETSCSF_ROOT2LEAF) {
1114       PetscCall(PetscSFLinkUnpackLeafData(sf, link, PETSCSF_LOCAL, leafdata, op));
1115     } else {
1116       PetscCall(PetscSFLinkUnpackRootData(sf, link, PETSCSF_LOCAL, rootdata, op));
1117     }
1118   } else {
1119     dstdups  = (direction == PETSCSF_ROOT2LEAF) ? sf->leafdups[PETSCSF_LOCAL] : bas->rootdups[PETSCSF_LOCAL];
1120     dstmtype = (direction == PETSCSF_ROOT2LEAF) ? link->leafmtype : link->rootmtype;
1121     PetscCall(PetscSFLinkGetScatterAndOp(link, dstmtype, op, dstdups, &ScatterAndOp));
1122     if (ScatterAndOp) {
1123       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1124       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1125       if (direction == PETSCSF_ROOT2LEAF) {
1126         PetscCall((*ScatterAndOp)(link, count, rootstart, rootopt, rootindices, rootdata, leafstart, leafopt, leafindices, leafdata));
1127       } else {
1128         PetscCall((*ScatterAndOp)(link, count, leafstart, leafopt, leafindices, leafdata, rootstart, rootopt, rootindices, rootdata));
1129       }
1130     } else {
1131       PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1132       PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, PETSC_MEMTYPE_HOST, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1133       if (direction == PETSCSF_ROOT2LEAF) {
1134         PetscCall(PetscSFLinkScatterDataWithMPIReduceLocal(sf, link, count, rootstart, rootindices, rootdata, leafstart, leafindices, leafdata, op));
1135       } else {
1136         PetscCall(PetscSFLinkScatterDataWithMPIReduceLocal(sf, link, count, leafstart, leafindices, leafdata, rootstart, rootindices, rootdata, op));
1137       }
1138     }
1139   }
1140   PetscFunctionReturn(PETSC_SUCCESS);
1141 }
1142 
1143 /* Fetch rootdata to leafdata and leafupdate locally */
1144 PetscErrorCode PetscSFLinkFetchAndOpLocal(PetscSF sf, PetscSFLink link, void *rootdata, const void *leafdata, void *leafupdate, MPI_Op op)
1145 {
1146   const PetscInt    *rootindices = NULL, *leafindices = NULL;
1147   PetscInt           count, rootstart, leafstart;
1148   PetscSF_Basic     *bas       = (PetscSF_Basic *)sf->data;
1149   const PetscMemType rootmtype = link->rootmtype, leafmtype = link->leafmtype;
1150   PetscSFPackOpt     leafopt = NULL, rootopt = NULL;
1151   PetscErrorCode (*FetchAndOpLocal)(PetscSFLink, PetscInt, PetscInt, PetscSFPackOpt, const PetscInt *, void *, PetscInt, PetscSFPackOpt, const PetscInt *, const void *, void *) = NULL;
1152 
1153   PetscFunctionBegin;
1154   if (!bas->rootbuflen[PETSCSF_LOCAL]) PetscFunctionReturn(PETSC_SUCCESS);
1155   if (rootmtype != leafmtype) {
1156     /* The local communication has to go through pack and unpack */
1157     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Doing PetscSFFetchAndOp with rootdata and leafdata on opposite side of CPU and GPU");
1158   } else {
1159     PetscCall(PetscSFLinkGetRootPackOptAndIndices(sf, link, rootmtype, PETSCSF_LOCAL, &count, &rootstart, &rootopt, &rootindices));
1160     PetscCall(PetscSFLinkGetLeafPackOptAndIndices(sf, link, leafmtype, PETSCSF_LOCAL, &count, &leafstart, &leafopt, &leafindices));
1161     PetscCall(PetscSFLinkGetFetchAndOpLocal(link, rootmtype, op, bas->rootdups[PETSCSF_LOCAL], &FetchAndOpLocal));
1162     PetscCall((*FetchAndOpLocal)(link, count, rootstart, rootopt, rootindices, rootdata, leafstart, leafopt, leafindices, leafdata, leafupdate));
1163   }
1164   PetscFunctionReturn(PETSC_SUCCESS);
1165 }
1166 
1167 /*
1168   Create per-rank pack/unpack optimizations based on indices patterns
1169 
1170    Input Parameters:
1171   +  n       - Number of destination ranks
1172   .  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.
1173   -  idx     - [*]   Array storing indices
1174 
1175    Output Parameters:
1176   +  opt     - Pack optimizations. NULL if no optimizations.
1177 */
1178 static PetscErrorCode PetscSFCreatePackOpt(PetscInt n, const PetscInt *offset, const PetscInt *idx, PetscSFPackOpt *out)
1179 {
1180   PetscInt       r, p, start, i, j, k, dx, dy, dz, dydz, m, X, Y;
1181   PetscBool      optimizable = PETSC_TRUE;
1182   PetscSFPackOpt opt;
1183 
1184   PetscFunctionBegin;
1185   PetscCall(PetscMalloc1(1, &opt));
1186   PetscCall(PetscMalloc1(7 * n + 2, &opt->array));
1187   opt->n = opt->array[0] = n;
1188   opt->offset            = opt->array + 1;
1189   opt->start             = opt->array + n + 2;
1190   opt->dx                = opt->array + 2 * n + 2;
1191   opt->dy                = opt->array + 3 * n + 2;
1192   opt->dz                = opt->array + 4 * n + 2;
1193   opt->X                 = opt->array + 5 * n + 2;
1194   opt->Y                 = opt->array + 6 * n + 2;
1195 
1196   for (r = 0; r < n; r++) {            /* For each destination rank */
1197     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 */
1198     p     = offset[r];
1199     start = idx[p]; /* First index for this rank */
1200     p++;
1201 
1202     /* Search in X dimension */
1203     for (dx = 1; dx < m; dx++, p++) {
1204       if (start + dx != idx[p]) break;
1205     }
1206 
1207     dydz = m / dx;
1208     X    = dydz > 1 ? (idx[p] - start) : dx;
1209     /* Not optimizable if m is not a multiple of dx, or some unrecognized pattern is found */
1210     if (m % dx || X <= 0) {
1211       optimizable = PETSC_FALSE;
1212       goto finish;
1213     }
1214     for (dy = 1; dy < dydz; dy++) { /* Search in Y dimension */
1215       for (i = 0; i < dx; i++, p++) {
1216         if (start + X * dy + i != idx[p]) {
1217           if (i) {
1218             optimizable = PETSC_FALSE;
1219             goto finish;
1220           } /* The pattern is violated in the middle of an x-walk */
1221           else
1222             goto Z_dimension;
1223         }
1224       }
1225     }
1226 
1227   Z_dimension:
1228     dz = m / (dx * dy);
1229     Y  = dz > 1 ? (idx[p] - start) / X : dy;
1230     /* Not optimizable if m is not a multiple of dx*dy, or some unrecognized pattern is found */
1231     if (m % (dx * dy) || Y <= 0) {
1232       optimizable = PETSC_FALSE;
1233       goto finish;
1234     }
1235     for (k = 1; k < dz; k++) { /* Go through Z dimension to see if remaining indices follow the pattern */
1236       for (j = 0; j < dy; j++) {
1237         for (i = 0; i < dx; i++, p++) {
1238           if (start + X * Y * k + X * j + i != idx[p]) {
1239             optimizable = PETSC_FALSE;
1240             goto finish;
1241           }
1242         }
1243       }
1244     }
1245     opt->start[r] = start;
1246     opt->dx[r]    = dx;
1247     opt->dy[r]    = dy;
1248     opt->dz[r]    = dz;
1249     opt->X[r]     = X;
1250     opt->Y[r]     = Y;
1251   }
1252 
1253 finish:
1254   /* If not optimizable, free arrays to save memory */
1255   if (!n || !optimizable) {
1256     PetscCall(PetscFree(opt->array));
1257     PetscCall(PetscFree(opt));
1258     *out = NULL;
1259   } else {
1260     opt->offset[0] = 0;
1261     for (r = 0; r < n; r++) opt->offset[r + 1] = opt->offset[r] + opt->dx[r] * opt->dy[r] * opt->dz[r];
1262     *out = opt;
1263   }
1264   PetscFunctionReturn(PETSC_SUCCESS);
1265 }
1266 
1267 static inline PetscErrorCode PetscSFDestroyPackOpt(PetscSF sf, PetscMemType mtype, PetscSFPackOpt *out)
1268 {
1269   PetscSFPackOpt opt = *out;
1270 
1271   PetscFunctionBegin;
1272   if (opt) {
1273     PetscCall(PetscSFFree(sf, mtype, opt->array));
1274     PetscCall(PetscFree(opt));
1275     *out = NULL;
1276   }
1277   PetscFunctionReturn(PETSC_SUCCESS);
1278 }
1279 
1280 PetscErrorCode PetscSFSetUpPackFields(PetscSF sf)
1281 {
1282   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1283   PetscInt       i, j;
1284 
1285   PetscFunctionBegin;
1286   /* [0] for PETSCSF_LOCAL and [1] for PETSCSF_REMOTE in the following */
1287   for (i = 0; i < 2; i++) { /* Set defaults */
1288     sf->leafstart[i]   = 0;
1289     sf->leafcontig[i]  = PETSC_TRUE;
1290     sf->leafdups[i]    = PETSC_FALSE;
1291     bas->rootstart[i]  = 0;
1292     bas->rootcontig[i] = PETSC_TRUE;
1293     bas->rootdups[i]   = PETSC_FALSE;
1294   }
1295 
1296   sf->leafbuflen[0] = sf->roffset[sf->ndranks];
1297   sf->leafbuflen[1] = sf->roffset[sf->nranks] - sf->roffset[sf->ndranks];
1298 
1299   if (sf->leafbuflen[0]) sf->leafstart[0] = sf->rmine[0];
1300   if (sf->leafbuflen[1]) sf->leafstart[1] = sf->rmine[sf->roffset[sf->ndranks]];
1301 
1302   /* Are leaf indices for self and remote contiguous? If yes, it is best for pack/unpack */
1303   for (i = 0; i < sf->roffset[sf->ndranks]; i++) { /* self */
1304     if (sf->rmine[i] != sf->leafstart[0] + i) {
1305       sf->leafcontig[0] = PETSC_FALSE;
1306       break;
1307     }
1308   }
1309   for (i = sf->roffset[sf->ndranks], j = 0; i < sf->roffset[sf->nranks]; i++, j++) { /* remote */
1310     if (sf->rmine[i] != sf->leafstart[1] + j) {
1311       sf->leafcontig[1] = PETSC_FALSE;
1312       break;
1313     }
1314   }
1315 
1316   /* If not, see if we can have per-rank optimizations by doing index analysis */
1317   if (!sf->leafcontig[0]) PetscCall(PetscSFCreatePackOpt(sf->ndranks, sf->roffset, sf->rmine, &sf->leafpackopt[0]));
1318   if (!sf->leafcontig[1]) PetscCall(PetscSFCreatePackOpt(sf->nranks - sf->ndranks, sf->roffset + sf->ndranks, sf->rmine, &sf->leafpackopt[1]));
1319 
1320   /* Are root indices for self and remote contiguous? */
1321   bas->rootbuflen[0] = bas->ioffset[bas->ndiranks];
1322   bas->rootbuflen[1] = bas->ioffset[bas->niranks] - bas->ioffset[bas->ndiranks];
1323 
1324   if (bas->rootbuflen[0]) bas->rootstart[0] = bas->irootloc[0];
1325   if (bas->rootbuflen[1]) bas->rootstart[1] = bas->irootloc[bas->ioffset[bas->ndiranks]];
1326 
1327   for (i = 0; i < bas->ioffset[bas->ndiranks]; i++) {
1328     if (bas->irootloc[i] != bas->rootstart[0] + i) {
1329       bas->rootcontig[0] = PETSC_FALSE;
1330       break;
1331     }
1332   }
1333   for (i = bas->ioffset[bas->ndiranks], j = 0; i < bas->ioffset[bas->niranks]; i++, j++) {
1334     if (bas->irootloc[i] != bas->rootstart[1] + j) {
1335       bas->rootcontig[1] = PETSC_FALSE;
1336       break;
1337     }
1338   }
1339 
1340   if (!bas->rootcontig[0]) PetscCall(PetscSFCreatePackOpt(bas->ndiranks, bas->ioffset, bas->irootloc, &bas->rootpackopt[0]));
1341   if (!bas->rootcontig[1]) PetscCall(PetscSFCreatePackOpt(bas->niranks - bas->ndiranks, bas->ioffset + bas->ndiranks, bas->irootloc, &bas->rootpackopt[1]));
1342 
1343   /* 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 */
1344   if (PetscDefined(HAVE_DEVICE)) {
1345     PetscBool ismulti = (sf->multi == sf) ? PETSC_TRUE : PETSC_FALSE;
1346     if (!sf->leafcontig[0] && !ismulti) PetscCall(PetscCheckDupsInt(sf->leafbuflen[0], sf->rmine, &sf->leafdups[0]));
1347     if (!sf->leafcontig[1] && !ismulti) PetscCall(PetscCheckDupsInt(sf->leafbuflen[1], sf->rmine + sf->roffset[sf->ndranks], &sf->leafdups[1]));
1348     if (!bas->rootcontig[0] && !ismulti) PetscCall(PetscCheckDupsInt(bas->rootbuflen[0], bas->irootloc, &bas->rootdups[0]));
1349     if (!bas->rootcontig[1] && !ismulti) PetscCall(PetscCheckDupsInt(bas->rootbuflen[1], bas->irootloc + bas->ioffset[bas->ndiranks], &bas->rootdups[1]));
1350   }
1351   PetscFunctionReturn(PETSC_SUCCESS);
1352 }
1353 
1354 PetscErrorCode PetscSFResetPackFields(PetscSF sf)
1355 {
1356   PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
1357   PetscInt       i;
1358 
1359   PetscFunctionBegin;
1360   for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
1361     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_HOST, &sf->leafpackopt[i]));
1362     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_HOST, &bas->rootpackopt[i]));
1363 #if defined(PETSC_HAVE_DEVICE)
1364     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_DEVICE, &sf->leafpackopt_d[i]));
1365     PetscCall(PetscSFDestroyPackOpt(sf, PETSC_MEMTYPE_DEVICE, &bas->rootpackopt_d[i]));
1366 #endif
1367   }
1368   PetscFunctionReturn(PETSC_SUCCESS);
1369 }
1370