1 #include <petscvec.h> 2 #include <petsc/private/partitionerimpl.h> /*I "petscpartitioner.h" I*/ 3 4 typedef struct { 5 PetscInt dummy; 6 } PetscPartitioner_Simple; 7 8 static PetscErrorCode PetscPartitionerDestroy_Simple(PetscPartitioner part) 9 { 10 PetscErrorCode ierr; 11 12 PetscFunctionBegin; 13 ierr = PetscFree(part->data);CHKERRQ(ierr); 14 PetscFunctionReturn(0); 15 } 16 17 static PetscErrorCode PetscPartitionerView_Simple_ASCII(PetscPartitioner part, PetscViewer viewer) 18 { 19 PetscFunctionBegin; 20 PetscFunctionReturn(0); 21 } 22 23 static PetscErrorCode PetscPartitionerView_Simple(PetscPartitioner part, PetscViewer viewer) 24 { 25 PetscBool iascii; 26 PetscErrorCode ierr; 27 28 PetscFunctionBegin; 29 PetscValidHeaderSpecific(part, PETSCPARTITIONER_CLASSID, 1); 30 PetscValidHeaderSpecific(viewer, PETSC_VIEWER_CLASSID, 2); 31 ierr = PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &iascii);CHKERRQ(ierr); 32 if (iascii) {ierr = PetscPartitionerView_Simple_ASCII(part, viewer);CHKERRQ(ierr);} 33 PetscFunctionReturn(0); 34 } 35 36 static PetscErrorCode PetscPartitionerPartition_Simple(PetscPartitioner part, PetscInt nparts, PetscInt numVertices, PetscInt start[], PetscInt adjacency[], PetscSection vertSection, PetscSection targetSection, PetscSection partSection, IS *partition) 37 { 38 MPI_Comm comm; 39 PetscInt np, *tpwgts = NULL, sumw = 0, numVerticesGlobal = 0; 40 PetscMPIInt size; 41 PetscErrorCode ierr; 42 43 PetscFunctionBegin; 44 if (vertSection) { ierr = PetscInfo(part,"PETSCPARTITIONERSIMPLE ignores vertex weights\n");CHKERRQ(ierr); } 45 comm = PetscObjectComm((PetscObject)part); 46 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 47 if (targetSection) { 48 ierr = MPIU_Allreduce(&numVertices, &numVerticesGlobal, 1, MPIU_INT, MPI_SUM, comm);CHKERRQ(ierr); 49 ierr = PetscCalloc1(nparts,&tpwgts);CHKERRQ(ierr); 50 for (np = 0; np < nparts; ++np) { 51 ierr = PetscSectionGetDof(targetSection,np,&tpwgts[np]);CHKERRQ(ierr); 52 sumw += tpwgts[np]; 53 } 54 if (sumw) { 55 PetscInt m,mp; 56 for (np = 0; np < nparts; ++np) tpwgts[np] = (tpwgts[np]*numVerticesGlobal)/sumw; 57 for (np = 0, m = -1, mp = 0, sumw = 0; np < nparts; ++np) { 58 if (m < tpwgts[np]) { m = tpwgts[np]; mp = np; } 59 sumw += tpwgts[np]; 60 } 61 if (sumw != numVerticesGlobal) tpwgts[mp] += numVerticesGlobal - sumw; 62 } 63 if (!sumw) {ierr = PetscFree(tpwgts);CHKERRQ(ierr);} 64 } 65 66 ierr = ISCreateStride(PETSC_COMM_SELF, numVertices, 0, 1, partition);CHKERRQ(ierr); 67 if (size == 1) { 68 if (tpwgts) { 69 for (np = 0; np < nparts; ++np) { 70 ierr = PetscSectionSetDof(partSection, np, tpwgts[np]);CHKERRQ(ierr); 71 } 72 } else { 73 for (np = 0; np < nparts; ++np) { 74 ierr = PetscSectionSetDof(partSection, np, numVertices/nparts + ((numVertices % nparts) > np));CHKERRQ(ierr); 75 } 76 } 77 } else { 78 if (tpwgts) { 79 Vec v; 80 PetscScalar *array; 81 PetscInt st,j; 82 PetscMPIInt rank; 83 84 ierr = VecCreate(comm,&v);CHKERRQ(ierr); 85 ierr = VecSetSizes(v,numVertices,numVerticesGlobal);CHKERRQ(ierr); 86 ierr = VecSetType(v,VECSTANDARD);CHKERRQ(ierr); 87 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 88 for (np = 0,st = 0; np < nparts; ++np) { 89 if (rank == np || (rank == size-1 && size < nparts && np >= size)) { 90 for (j = 0; j < tpwgts[np]; j++) { 91 ierr = VecSetValue(v,st+j,np,INSERT_VALUES);CHKERRQ(ierr); 92 } 93 } 94 st += tpwgts[np]; 95 } 96 ierr = VecAssemblyBegin(v);CHKERRQ(ierr); 97 ierr = VecAssemblyEnd(v);CHKERRQ(ierr); 98 ierr = VecGetArray(v,&array);CHKERRQ(ierr); 99 for (j = 0; j < numVertices; ++j) { 100 ierr = PetscSectionAddDof(partSection,PetscRealPart(array[j]),1);CHKERRQ(ierr); 101 } 102 ierr = VecRestoreArray(v,&array);CHKERRQ(ierr); 103 ierr = VecDestroy(&v);CHKERRQ(ierr); 104 } else { 105 PetscMPIInt rank; 106 PetscInt nvGlobal, *offsets, myFirst, myLast; 107 108 ierr = PetscMalloc1(size+1,&offsets);CHKERRQ(ierr); 109 offsets[0] = 0; 110 ierr = MPI_Allgather(&numVertices,1,MPIU_INT,&offsets[1],1,MPIU_INT,comm);CHKERRQ(ierr); 111 for (np = 2; np <= size; np++) { 112 offsets[np] += offsets[np-1]; 113 } 114 nvGlobal = offsets[size]; 115 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 116 myFirst = offsets[rank]; 117 myLast = offsets[rank + 1] - 1; 118 ierr = PetscFree(offsets);CHKERRQ(ierr); 119 if (numVertices) { 120 PetscInt firstPart = 0, firstLargePart = 0; 121 PetscInt lastPart = 0, lastLargePart = 0; 122 PetscInt rem = nvGlobal % nparts; 123 PetscInt pSmall = nvGlobal/nparts; 124 PetscInt pBig = nvGlobal/nparts + 1; 125 126 if (rem) { 127 firstLargePart = myFirst / pBig; 128 lastLargePart = myLast / pBig; 129 130 if (firstLargePart < rem) { 131 firstPart = firstLargePart; 132 } else { 133 firstPart = rem + (myFirst - (rem * pBig)) / pSmall; 134 } 135 if (lastLargePart < rem) { 136 lastPart = lastLargePart; 137 } else { 138 lastPart = rem + (myLast - (rem * pBig)) / pSmall; 139 } 140 } else { 141 firstPart = myFirst / (nvGlobal/nparts); 142 lastPart = myLast / (nvGlobal/nparts); 143 } 144 145 for (np = firstPart; np <= lastPart; np++) { 146 PetscInt PartStart = np * (nvGlobal/nparts) + PetscMin(nvGlobal % nparts,np); 147 PetscInt PartEnd = (np+1) * (nvGlobal/nparts) + PetscMin(nvGlobal % nparts,np+1); 148 149 PartStart = PetscMax(PartStart,myFirst); 150 PartEnd = PetscMin(PartEnd,myLast+1); 151 ierr = PetscSectionSetDof(partSection,np,PartEnd-PartStart);CHKERRQ(ierr); 152 } 153 } 154 } 155 } 156 ierr = PetscFree(tpwgts);CHKERRQ(ierr); 157 PetscFunctionReturn(0); 158 } 159 160 static PetscErrorCode PetscPartitionerInitialize_Simple(PetscPartitioner part) 161 { 162 PetscFunctionBegin; 163 part->noGraph = PETSC_TRUE; 164 part->ops->view = PetscPartitionerView_Simple; 165 part->ops->destroy = PetscPartitionerDestroy_Simple; 166 part->ops->partition = PetscPartitionerPartition_Simple; 167 PetscFunctionReturn(0); 168 } 169 170 /*MC 171 PETSCPARTITIONERSIMPLE = "simple" - A PetscPartitioner object 172 173 Level: intermediate 174 175 .seealso: PetscPartitionerType, PetscPartitionerCreate(), PetscPartitionerSetType() 176 M*/ 177 178 PETSC_EXTERN PetscErrorCode PetscPartitionerCreate_Simple(PetscPartitioner part) 179 { 180 PetscPartitioner_Simple *p; 181 PetscErrorCode ierr; 182 183 PetscFunctionBegin; 184 PetscValidHeaderSpecific(part, PETSCPARTITIONER_CLASSID, 1); 185 ierr = PetscNewLog(part, &p);CHKERRQ(ierr); 186 part->data = p; 187 188 ierr = PetscPartitionerInitialize_Simple(part);CHKERRQ(ierr); 189 PetscFunctionReturn(0); 190 } 191