Actual source code: partsimple.c
1: #include <petscvec.h>
2: #include <petsc/private/partitionerimpl.h>
4: typedef struct {
5: PetscBool useGrid; /* Flag to use a grid layout */
6: PetscInt gridDim; /* The grid dimension */
7: PetscInt nodeGrid[3]; /* Dimension of node grid */
8: PetscInt processGrid[3]; /* Dimension of local process grid on each node */
9: } PetscPartitioner_Simple;
11: static PetscErrorCode PetscPartitionerDestroy_Simple(PetscPartitioner part)
12: {
13: PetscFunctionBegin;
14: PetscCall(PetscFree(part->data));
15: PetscFunctionReturn(PETSC_SUCCESS);
16: }
18: static PetscErrorCode PetscPartitionerSetFromOptions_Simple(PetscPartitioner part, PetscOptionItems PetscOptionsObject)
19: {
20: PetscPartitioner_Simple *p = (PetscPartitioner_Simple *)part->data;
21: PetscInt num, i;
22: PetscBool flg;
24: PetscFunctionBegin;
25: for (i = 0; i < 3; ++i) p->processGrid[i] = p->nodeGrid[i] = 1;
26: PetscOptionsHeadBegin(PetscOptionsObject, "PetscPartitioner Simple Options");
27: num = 3;
28: PetscCall(PetscOptionsIntArray("-petscpartitioner_simple_node_grid", "Number of nodes in each dimension", "", p->nodeGrid, &num, &flg));
29: if (flg) {
30: p->useGrid = PETSC_TRUE;
31: p->gridDim = num;
32: }
33: num = 3;
34: PetscCall(PetscOptionsIntArray("-petscpartitioner_simple_process_grid", "Number of local processes in each dimension for a given node", "", p->processGrid, &num, &flg));
35: if (flg) {
36: p->useGrid = PETSC_TRUE;
37: if (p->gridDim < 0) p->gridDim = num;
38: else PetscCheck(p->gridDim == num, PetscObjectComm((PetscObject)part), PETSC_ERR_ARG_INCOMP, "Process grid dimension %" PetscInt_FMT " != %" PetscInt_FMT " node grid dimension", num, p->gridDim);
39: }
40: PetscOptionsHeadEnd();
41: PetscFunctionReturn(PETSC_SUCCESS);
42: }
44: static PetscErrorCode PetscPartitionerPartition_Simple_Grid(PetscPartitioner part, PetscInt nparts, PetscInt numVertices, PetscInt start[], PetscInt adjacency[], PetscSection vertSection, PetscSection targetSection, PetscSection partSection, IS *partition)
45: {
46: PetscPartitioner_Simple *p = (PetscPartitioner_Simple *)part->data;
47: const PetscInt *nodes = p->nodeGrid;
48: const PetscInt *procs = p->processGrid;
49: PetscInt *cellproc, *offsets, cells[3] = {1, 1, 1}, pcells[3] = {1, 1, 1};
50: PetscInt Np = 1, Nr, np, nk, nj, ni, pk, pj, pi, ck, cj, ci, i;
51: MPI_Comm comm;
52: PetscMPIInt size;
54: PetscFunctionBegin;
55: if (vertSection) PetscCall(PetscInfo(part, "PETSCPARTITIONERSIMPLE ignores vertex weights when using grid partition\n"));
56: if (targetSection) PetscCall(PetscInfo(part, "PETSCPARTITIONERSIMPLE ignores partition weights when using grid partition\n"));
57: PetscCall(PetscObjectGetComm((PetscObject)part, &comm));
58: PetscCallMPI(MPI_Comm_size(comm, &size));
59: /* Check grid */
60: for (i = 0; i < 3; ++i) Np *= nodes[i] * procs[i];
61: PetscCheck(nparts == Np, comm, PETSC_ERR_ARG_INCOMP, "Number of partitions %" PetscInt_FMT " != %" PetscInt_FMT " grid size", nparts, Np);
62: PetscCheck(nparts == size, comm, PETSC_ERR_ARG_INCOMP, "Number of partitions %" PetscInt_FMT " != %d processes", nparts, size);
63: PetscCheck(numVertices % nparts == 0, comm, PETSC_ERR_ARG_INCOMP, "Number of cells %" PetscInt_FMT " is not divisible by number of partitions %" PetscInt_FMT, numVertices, nparts);
64: for (i = 0; i < p->gridDim; ++i) cells[i] = nodes[i] * procs[i];
65: Nr = numVertices / nparts;
66: while (Nr > 1) {
67: for (i = 0; i < p->gridDim; ++i) {
68: cells[i] *= 2;
69: Nr /= 2;
70: }
71: }
72: PetscCheck(!numVertices || Nr == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Odd number of cells %" PetscInt_FMT ". Must be nprocs*2^k", numVertices);
73: for (i = 0; i < p->gridDim; ++i) {
74: PetscCheck(cells[i] % (nodes[i] * procs[i]) == 0, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "dir %" PetscInt_FMT ". Number of cells (%" PetscInt_FMT ") mod number of processors %" PetscInt_FMT, i, cells[i], nodes[i] * procs[i]);
75: pcells[i] = cells[i] / (nodes[i] * procs[i]);
76: }
77: /* Compute sizes */
78: for (np = 0; np < nparts; ++np) PetscCall(PetscSectionSetDof(partSection, np, numVertices / nparts));
79: PetscCall(PetscSectionSetUp(partSection));
80: PetscCall(PetscCalloc1(nparts, &offsets));
81: for (np = 0; np < nparts; ++np) PetscCall(PetscSectionGetOffset(partSection, np, &offsets[np]));
82: if (!numVertices) pcells[0] = pcells[1] = pcells[2] = 0;
83: /* Compute partition */
84: PetscCall(PetscMalloc1(numVertices, &cellproc));
85: for (nk = 0; nk < nodes[2]; ++nk) {
86: for (nj = 0; nj < nodes[1]; ++nj) {
87: for (ni = 0; ni < nodes[0]; ++ni) {
88: const PetscInt nid = (nk * nodes[1] + nj) * nodes[0] + ni;
90: for (pk = 0; pk < procs[2]; ++pk) {
91: for (pj = 0; pj < procs[1]; ++pj) {
92: for (pi = 0; pi < procs[0]; ++pi) {
93: const PetscInt pid = ((nid * procs[2] + pk) * procs[1] + pj) * procs[0] + pi;
95: /* Assume that cells are originally numbered lexicographically */
96: for (ck = 0; ck < pcells[2]; ++ck) {
97: for (cj = 0; cj < pcells[1]; ++cj) {
98: for (ci = 0; ci < pcells[0]; ++ci) {
99: const PetscInt cid = (((nk * procs[2] + pk) * pcells[2] + ck) * cells[1] + ((nj * procs[1] + pj) * pcells[1] + cj)) * cells[0] + (ni * procs[0] + pi) * pcells[0] + ci;
101: cellproc[offsets[pid]++] = cid;
102: }
103: }
104: }
105: }
106: }
107: }
108: }
109: }
110: }
111: for (np = 1; np < nparts; ++np) PetscCheck(offsets[np] - offsets[np - 1] == numVertices / nparts, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Offset %" PetscInt_FMT " != %" PetscInt_FMT " partition size", offsets[np], numVertices / nparts);
112: PetscCall(PetscFree(offsets));
113: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numVertices, cellproc, PETSC_OWN_POINTER, partition));
114: PetscFunctionReturn(PETSC_SUCCESS);
115: }
117: static PetscErrorCode PetscPartitionerPartition_Simple(PetscPartitioner part, PetscInt nparts, PetscInt numVertices, PetscInt start[], PetscInt adjacency[], PetscSection vertSection, PetscSection edgeSection, PetscSection targetSection, PetscSection partSection, IS *partition)
118: {
119: PetscPartitioner_Simple *p = (PetscPartitioner_Simple *)part->data;
120: MPI_Comm comm;
121: PetscInt np, *tpwgts = NULL, sumw = 0, numVerticesGlobal = 0;
122: PetscMPIInt size;
124: PetscFunctionBegin;
125: if (p->useGrid) {
126: PetscCall(PetscPartitionerPartition_Simple_Grid(part, nparts, numVertices, start, adjacency, vertSection, targetSection, partSection, partition));
127: PetscFunctionReturn(PETSC_SUCCESS);
128: }
129: if (vertSection) PetscCall(PetscInfo(part, "PETSCPARTITIONERSIMPLE ignores vertex weights\n"));
130: PetscCall(PetscObjectGetComm((PetscObject)part, &comm));
131: PetscCallMPI(MPI_Comm_size(comm, &size));
132: if (targetSection) {
133: PetscCallMPI(MPIU_Allreduce(&numVertices, &numVerticesGlobal, 1, MPIU_INT, MPI_SUM, comm));
134: PetscCall(PetscCalloc1(nparts, &tpwgts));
135: for (np = 0; np < nparts; ++np) {
136: PetscCall(PetscSectionGetDof(targetSection, np, &tpwgts[np]));
137: sumw += tpwgts[np];
138: }
139: if (sumw) {
140: PetscInt m, mp;
141: for (np = 0; np < nparts; ++np) tpwgts[np] = (tpwgts[np] * numVerticesGlobal) / sumw;
142: for (np = 0, m = -1, mp = 0, sumw = 0; np < nparts; ++np) {
143: if (m < tpwgts[np]) {
144: m = tpwgts[np];
145: mp = np;
146: }
147: sumw += tpwgts[np];
148: }
149: if (sumw != numVerticesGlobal) tpwgts[mp] += numVerticesGlobal - sumw;
150: }
151: if (!sumw) PetscCall(PetscFree(tpwgts));
152: }
154: PetscCall(ISCreateStride(PETSC_COMM_SELF, numVertices, 0, 1, partition));
155: if (size == 1) {
156: if (tpwgts) {
157: for (np = 0; np < nparts; ++np) PetscCall(PetscSectionSetDof(partSection, np, tpwgts[np]));
158: } else {
159: for (np = 0; np < nparts; ++np) PetscCall(PetscSectionSetDof(partSection, np, numVertices / nparts + ((numVertices % nparts) > np)));
160: }
161: } else {
162: if (tpwgts) {
163: Vec v;
164: PetscScalar *array;
165: PetscInt st, j;
166: PetscMPIInt rank;
168: PetscCall(VecCreate(comm, &v));
169: PetscCall(VecSetSizes(v, numVertices, numVerticesGlobal));
170: PetscCall(VecSetType(v, VECSTANDARD));
171: PetscCallMPI(MPI_Comm_rank(comm, &rank));
172: for (np = 0, st = 0; np < nparts; ++np) {
173: if (rank == np || (rank == size - 1 && size < nparts && np >= size)) {
174: for (j = 0; j < tpwgts[np]; j++) PetscCall(VecSetValue(v, st + j, np, INSERT_VALUES));
175: }
176: st += tpwgts[np];
177: }
178: PetscCall(VecAssemblyBegin(v));
179: PetscCall(VecAssemblyEnd(v));
180: PetscCall(VecGetArray(v, &array));
181: for (j = 0; j < numVertices; ++j) PetscCall(PetscSectionAddDof(partSection, PetscRealPart(array[j]), 1));
182: PetscCall(VecRestoreArray(v, &array));
183: PetscCall(VecDestroy(&v));
184: } else {
185: PetscMPIInt rank;
186: PetscInt nvGlobal, *offsets, myFirst, myLast;
188: PetscCall(PetscMalloc1(size + 1, &offsets));
189: offsets[0] = 0;
190: PetscCallMPI(MPI_Allgather(&numVertices, 1, MPIU_INT, &offsets[1], 1, MPIU_INT, comm));
191: for (np = 2; np <= size; np++) offsets[np] += offsets[np - 1];
192: nvGlobal = offsets[size];
193: PetscCallMPI(MPI_Comm_rank(comm, &rank));
194: myFirst = offsets[rank];
195: myLast = offsets[rank + 1] - 1;
196: PetscCall(PetscFree(offsets));
197: if (numVertices) {
198: PetscInt firstPart = 0, firstLargePart = 0;
199: PetscInt lastPart = 0, lastLargePart = 0;
200: PetscInt rem = nvGlobal % nparts;
201: PetscInt pSmall = nvGlobal / nparts;
202: PetscInt pBig = nvGlobal / nparts + 1;
204: if (rem) {
205: firstLargePart = myFirst / pBig;
206: lastLargePart = myLast / pBig;
208: if (firstLargePart < rem) {
209: firstPart = firstLargePart;
210: } else {
211: firstPart = rem + (myFirst - (rem * pBig)) / pSmall;
212: }
213: if (lastLargePart < rem) {
214: lastPart = lastLargePart;
215: } else {
216: lastPart = rem + (myLast - (rem * pBig)) / pSmall;
217: }
218: } else {
219: firstPart = myFirst / (nvGlobal / nparts);
220: lastPart = myLast / (nvGlobal / nparts);
221: }
223: for (np = firstPart; np <= lastPart; np++) {
224: PetscInt PartStart = np * (nvGlobal / nparts) + PetscMin(nvGlobal % nparts, np);
225: PetscInt PartEnd = (np + 1) * (nvGlobal / nparts) + PetscMin(nvGlobal % nparts, np + 1);
227: PartStart = PetscMax(PartStart, myFirst);
228: PartEnd = PetscMin(PartEnd, myLast + 1);
229: PetscCall(PetscSectionSetDof(partSection, np, PartEnd - PartStart));
230: }
231: }
232: }
233: }
234: PetscCall(PetscFree(tpwgts));
235: PetscFunctionReturn(PETSC_SUCCESS);
236: }
238: static PetscErrorCode PetscPartitionerInitialize_Simple(PetscPartitioner part)
239: {
240: PetscFunctionBegin;
241: part->noGraph = PETSC_TRUE;
242: part->ops->setfromoptions = PetscPartitionerSetFromOptions_Simple;
243: part->ops->destroy = PetscPartitionerDestroy_Simple;
244: part->ops->partition = PetscPartitionerPartition_Simple;
245: PetscFunctionReturn(PETSC_SUCCESS);
246: }
248: /*MC
249: PETSCPARTITIONERSIMPLE = "simple" - A PetscPartitioner object
251: Level: intermediate
253: .seealso: `PetscPartitionerType`, `PetscPartitionerCreate()`, `PetscPartitionerSetType()`
254: M*/
256: PETSC_EXTERN PetscErrorCode PetscPartitionerCreate_Simple(PetscPartitioner part)
257: {
258: PetscPartitioner_Simple *p;
260: PetscFunctionBegin;
262: PetscCall(PetscNew(&p));
263: p->gridDim = -1;
264: part->data = p;
266: PetscCall(PetscPartitionerInitialize_Simple(part));
267: PetscFunctionReturn(PETSC_SUCCESS);
268: }