1 2 /* 3 Provides utility routines for split MPI communicator. 4 */ 5 #include <petscsys.h> /*I "petscsys.h" I*/ 6 #include <petsc-private/threadcommimpl.h> /* Petsc_ThreadComm_keyval */ 7 8 const char *const PetscSubcommTypes[] = {"GENERAL","CONTIGUOUS","INTERLACED","PetscSubcommType","PETSC_SUBCOMM_",0}; 9 10 extern PetscErrorCode PetscSubcommCreate_contiguous(PetscSubcomm); 11 extern PetscErrorCode PetscSubcommCreate_interlaced(PetscSubcomm); 12 13 #undef __FUNCT__ 14 #define __FUNCT__ "PetscSubcommSetNumber" 15 /*@C 16 PetscSubcommSetNumber - Set total number of subcommunicators. 17 18 Collective on MPI_Comm 19 20 Input Parameter: 21 + psubcomm - PetscSubcomm context 22 - nsubcomm - the total number of subcommunicators in psubcomm 23 24 Level: advanced 25 26 .keywords: communicator 27 28 .seealso: PetscSubcommCreate(),PetscSubcommDestroy(),PetscSubcommSetType(),PetscSubcommSetTypeGeneral() 29 @*/ 30 PetscErrorCode PetscSubcommSetNumber(PetscSubcomm psubcomm,PetscInt nsubcomm) 31 { 32 PetscErrorCode ierr; 33 MPI_Comm comm=psubcomm->parent; 34 PetscMPIInt rank,size; 35 36 PetscFunctionBegin; 37 if (!psubcomm) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"PetscSubcomm is not created. Call PetscSubcommCreate() first"); 38 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 39 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 40 if (nsubcomm < 1 || nsubcomm > size) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Num of subcommunicators %D cannot be < 1 or > input comm size %D",nsubcomm,size); 41 42 psubcomm->n = nsubcomm; 43 PetscFunctionReturn(0); 44 } 45 46 #undef __FUNCT__ 47 #define __FUNCT__ "PetscSubcommSetType" 48 /*@C 49 PetscSubcommSetType - Set type of subcommunicators. 50 51 Collective on MPI_Comm 52 53 Input Parameter: 54 + psubcomm - PetscSubcomm context 55 - subcommtype - subcommunicator type, PETSC_SUBCOMM_CONTIGUOUS,PETSC_SUBCOMM_INTERLACED 56 57 Level: advanced 58 59 .keywords: communicator 60 61 .seealso: PetscSubcommCreate(),PetscSubcommDestroy(),PetscSubcommSetNumber(),PetscSubcommSetTypeGeneral() 62 @*/ 63 PetscErrorCode PetscSubcommSetType(PetscSubcomm psubcomm,PetscSubcommType subcommtype) 64 { 65 PetscErrorCode ierr; 66 67 PetscFunctionBegin; 68 if (!psubcomm) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"PetscSubcomm is not created. Call PetscSubcommCreate()"); 69 if (psubcomm->n < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"number of subcommunicators %D is incorrect. Call PetscSubcommSetNumber()",psubcomm->n); 70 71 if (subcommtype == PETSC_SUBCOMM_CONTIGUOUS) { 72 ierr = PetscSubcommCreate_contiguous(psubcomm);CHKERRQ(ierr); 73 } else if (subcommtype == PETSC_SUBCOMM_INTERLACED) { 74 ierr = PetscSubcommCreate_interlaced(psubcomm);CHKERRQ(ierr); 75 } else SETERRQ1(psubcomm->parent,PETSC_ERR_SUP,"PetscSubcommType %D is not supported yet",subcommtype); 76 PetscFunctionReturn(0); 77 } 78 79 #undef __FUNCT__ 80 #define __FUNCT__ "PetscSubcommSetTypeGeneral" 81 /*@C 82 PetscSubcommSetTypeGeneral - Set type of subcommunicators from user's specifications 83 84 Collective on MPI_Comm 85 86 Input Parameter: 87 + psubcomm - PetscSubcomm context 88 . color - control of subset assignment (nonnegative integer). Processes with the same color are in the same subcommunicator. 89 . subrank - rank in the subcommunicator 90 - duprank - rank in the dupparent (see PetscSubcomm) 91 92 Level: advanced 93 94 .keywords: communicator, create 95 96 .seealso: PetscSubcommCreate(),PetscSubcommDestroy(),PetscSubcommSetNumber(),PetscSubcommSetType() 97 @*/ 98 PetscErrorCode PetscSubcommSetTypeGeneral(PetscSubcomm psubcomm,PetscMPIInt color,PetscMPIInt subrank,PetscMPIInt duprank) 99 { 100 PetscErrorCode ierr; 101 MPI_Comm subcomm=0,dupcomm=0,comm=psubcomm->parent; 102 PetscMPIInt size; 103 104 PetscFunctionBegin; 105 if (!psubcomm) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NULL,"PetscSubcomm is not created. Call PetscSubcommCreate()"); 106 if (psubcomm->n < 1) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"number of subcommunicators %D is incorrect. Call PetscSubcommSetNumber()",psubcomm->n); 107 108 ierr = MPI_Comm_split(comm,color,subrank,&subcomm);CHKERRQ(ierr); 109 110 /* create dupcomm with same size as comm, but its rank, duprank, maps subcomm's contiguously into dupcomm 111 if duprank is not a valid number, then dupcomm is not created - not all applications require dupcomm! */ 112 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 113 if (duprank == PETSC_DECIDE) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"duprank==PETSC_DECIDE is not supported yet"); 114 else if (duprank >= 0 && duprank < size) { 115 ierr = MPI_Comm_split(comm,0,duprank,&dupcomm);CHKERRQ(ierr); 116 } 117 ierr = PetscCommDuplicate(dupcomm,&psubcomm->dupparent,NULL);CHKERRQ(ierr); 118 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,NULL);CHKERRQ(ierr); 119 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 120 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 121 122 psubcomm->color = color; 123 PetscFunctionReturn(0); 124 } 125 126 #undef __FUNCT__ 127 #define __FUNCT__ "PetscSubcommDestroy" 128 PetscErrorCode PetscSubcommDestroy(PetscSubcomm *psubcomm) 129 { 130 PetscErrorCode ierr; 131 132 PetscFunctionBegin; 133 if (!*psubcomm) PetscFunctionReturn(0); 134 ierr = PetscCommDestroy(&(*psubcomm)->dupparent);CHKERRQ(ierr); 135 ierr = PetscCommDestroy(&(*psubcomm)->comm);CHKERRQ(ierr); 136 ierr = PetscFree((*psubcomm));CHKERRQ(ierr); 137 PetscFunctionReturn(0); 138 } 139 140 #undef __FUNCT__ 141 #define __FUNCT__ "PetscSubcommCreate" 142 /*@C 143 PetscSubcommCreate - Create a PetscSubcomm context. 144 145 Collective on MPI_Comm 146 147 Input Parameter: 148 . comm - MPI communicator 149 150 Output Parameter: 151 . psubcomm - location to store the PetscSubcomm context 152 153 Level: advanced 154 155 .keywords: communicator, create 156 157 .seealso: PetscSubcommDestroy() 158 @*/ 159 PetscErrorCode PetscSubcommCreate(MPI_Comm comm,PetscSubcomm *psubcomm) 160 { 161 PetscErrorCode ierr; 162 163 PetscFunctionBegin; 164 ierr = PetscNew(struct _n_PetscSubcomm,psubcomm);CHKERRQ(ierr); 165 166 (*psubcomm)->parent = comm; 167 PetscFunctionReturn(0); 168 } 169 170 #undef __FUNCT__ 171 #define __FUNCT__ "PetscSubcommCreate_contiguous" 172 PetscErrorCode PetscSubcommCreate_contiguous(PetscSubcomm psubcomm) 173 { 174 PetscErrorCode ierr; 175 PetscMPIInt rank,size,*subsize,duprank=-1,subrank=-1; 176 PetscInt np_subcomm,nleftover,i,color=-1,rankstart,nsubcomm=psubcomm->n; 177 MPI_Comm subcomm=0,dupcomm=0,comm=psubcomm->parent; 178 179 PetscFunctionBegin; 180 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 181 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 182 183 /* get size of each subcommunicator */ 184 ierr = PetscMalloc((1+nsubcomm)*sizeof(PetscMPIInt),&subsize);CHKERRQ(ierr); 185 186 np_subcomm = size/nsubcomm; 187 nleftover = size - nsubcomm*np_subcomm; 188 for (i=0; i<nsubcomm; i++) { 189 subsize[i] = np_subcomm; 190 if (i<nleftover) subsize[i]++; 191 } 192 193 /* get color and subrank of this proc */ 194 rankstart = 0; 195 for (i=0; i<nsubcomm; i++) { 196 if (rank >= rankstart && rank < rankstart+subsize[i]) { 197 color = i; 198 subrank = rank - rankstart; 199 duprank = rank; 200 break; 201 } else rankstart += subsize[i]; 202 } 203 ierr = PetscFree(subsize);CHKERRQ(ierr); 204 205 ierr = MPI_Comm_split(comm,color,subrank,&subcomm);CHKERRQ(ierr); 206 207 /* create dupcomm with same size as comm, but its rank, duprank, maps subcomm's contiguously into dupcomm */ 208 ierr = MPI_Comm_split(comm,0,duprank,&dupcomm);CHKERRQ(ierr); 209 { 210 PetscThreadComm tcomm; 211 ierr = PetscCommGetThreadComm(comm,&tcomm);CHKERRQ(ierr); 212 ierr = MPI_Attr_put(dupcomm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 213 tcomm->refct++; 214 ierr = MPI_Attr_put(subcomm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 215 tcomm->refct++; 216 } 217 ierr = PetscCommDuplicate(dupcomm,&psubcomm->dupparent,NULL);CHKERRQ(ierr); 218 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,NULL);CHKERRQ(ierr); 219 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 220 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 221 222 psubcomm->color = color; 223 psubcomm->type = PETSC_SUBCOMM_CONTIGUOUS; 224 PetscFunctionReturn(0); 225 } 226 227 #undef __FUNCT__ 228 #define __FUNCT__ "PetscSubcommCreate_interlaced" 229 /* 230 Note: 231 In PCREDUNDANT, to avoid data scattering from subcomm back to original comm, we create subcommunicators 232 by iteratively taking a process into a subcommunicator. 233 Example: size=4, nsubcomm=(*psubcomm)->n=3 234 comm=(*psubcomm)->parent: 235 rank: [0] [1] [2] [3] 236 color: 0 1 2 0 237 238 subcomm=(*psubcomm)->comm: 239 subrank: [0] [0] [0] [1] 240 241 dupcomm=(*psubcomm)->dupparent: 242 duprank: [0] [2] [3] [1] 243 244 Here, subcomm[color = 0] has subsize=2, owns process [0] and [3] 245 subcomm[color = 1] has subsize=1, owns process [1] 246 subcomm[color = 2] has subsize=1, owns process [2] 247 dupcomm has same number of processes as comm, and its duprank maps 248 processes in subcomm contiguously into a 1d array: 249 duprank: [0] [1] [2] [3] 250 rank: [0] [3] [1] [2] 251 subcomm[0] subcomm[1] subcomm[2] 252 */ 253 254 PetscErrorCode PetscSubcommCreate_interlaced(PetscSubcomm psubcomm) 255 { 256 PetscErrorCode ierr; 257 PetscMPIInt rank,size,*subsize,duprank,subrank; 258 PetscInt np_subcomm,nleftover,i,j,color,nsubcomm=psubcomm->n; 259 MPI_Comm subcomm=0,dupcomm=0,comm=psubcomm->parent; 260 261 PetscFunctionBegin; 262 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 263 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 264 265 /* get size of each subcommunicator */ 266 ierr = PetscMalloc((1+nsubcomm)*sizeof(PetscMPIInt),&subsize);CHKERRQ(ierr); 267 268 np_subcomm = size/nsubcomm; 269 nleftover = size - nsubcomm*np_subcomm; 270 for (i=0; i<nsubcomm; i++) { 271 subsize[i] = np_subcomm; 272 if (i<nleftover) subsize[i]++; 273 } 274 275 /* find color for this proc */ 276 color = rank%nsubcomm; 277 subrank = rank/nsubcomm; 278 279 ierr = MPI_Comm_split(comm,color,subrank,&subcomm);CHKERRQ(ierr); 280 281 j = 0; duprank = 0; 282 for (i=0; i<nsubcomm; i++) { 283 if (j == color) { 284 duprank += subrank; 285 break; 286 } 287 duprank += subsize[i]; j++; 288 } 289 ierr = PetscFree(subsize);CHKERRQ(ierr); 290 291 /* create dupcomm with same size as comm, but its rank, duprank, maps subcomm's contiguously into dupcomm */ 292 ierr = MPI_Comm_split(comm,0,duprank,&dupcomm);CHKERRQ(ierr); 293 { 294 PetscThreadComm tcomm; 295 ierr = PetscCommGetThreadComm(comm,&tcomm);CHKERRQ(ierr); 296 ierr = MPI_Attr_put(dupcomm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 297 tcomm->refct++; 298 ierr = MPI_Attr_put(subcomm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 299 tcomm->refct++; 300 } 301 ierr = PetscCommDuplicate(dupcomm,&psubcomm->dupparent,NULL);CHKERRQ(ierr); 302 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,NULL);CHKERRQ(ierr); 303 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 304 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 305 306 psubcomm->color = color; 307 psubcomm->type = PETSC_SUBCOMM_INTERLACED; 308 PetscFunctionReturn(0); 309 } 310 311 312