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,PETSC_NULL);CHKERRQ(ierr); 118 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,PETSC_NULL);CHKERRQ(ierr); 119 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 120 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 121 psubcomm->color = color; 122 PetscFunctionReturn(0); 123 } 124 125 #undef __FUNCT__ 126 #define __FUNCT__ "PetscSubcommDestroy" 127 PetscErrorCode PetscSubcommDestroy(PetscSubcomm *psubcomm) 128 { 129 PetscErrorCode ierr; 130 131 PetscFunctionBegin; 132 if (!*psubcomm) PetscFunctionReturn(0); 133 ierr = PetscCommDestroy(&(*psubcomm)->dupparent);CHKERRQ(ierr); 134 ierr = PetscCommDestroy(&(*psubcomm)->comm);CHKERRQ(ierr); 135 ierr = PetscFree((*psubcomm));CHKERRQ(ierr); 136 PetscFunctionReturn(0); 137 } 138 139 #undef __FUNCT__ 140 #define __FUNCT__ "PetscSubcommCreate" 141 /*@C 142 PetscSubcommCreate - Create a PetscSubcomm context. 143 144 Collective on MPI_Comm 145 146 Input Parameter: 147 . comm - MPI communicator 148 149 Output Parameter: 150 . psubcomm - location to store the PetscSubcomm context 151 152 Level: advanced 153 154 .keywords: communicator, create 155 156 .seealso: PetscSubcommDestroy() 157 @*/ 158 PetscErrorCode PetscSubcommCreate(MPI_Comm comm,PetscSubcomm *psubcomm) 159 { 160 PetscErrorCode ierr; 161 162 PetscFunctionBegin; 163 ierr = PetscNew(struct _n_PetscSubcomm,psubcomm);CHKERRQ(ierr); 164 (*psubcomm)->parent = comm; 165 PetscFunctionReturn(0); 166 } 167 168 #undef __FUNCT__ 169 #define __FUNCT__ "PetscSubcommCreate_contiguous" 170 PetscErrorCode PetscSubcommCreate_contiguous(PetscSubcomm psubcomm) 171 { 172 PetscErrorCode ierr; 173 PetscMPIInt rank,size,*subsize,duprank=-1,subrank=-1; 174 PetscInt np_subcomm,nleftover,i,color=-1,rankstart,nsubcomm=psubcomm->n; 175 MPI_Comm subcomm=0,dupcomm=0,comm=psubcomm->parent; 176 177 PetscFunctionBegin; 178 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 179 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 180 181 /* get size of each subcommunicator */ 182 ierr = PetscMalloc((1+nsubcomm)*sizeof(PetscMPIInt),&subsize);CHKERRQ(ierr); 183 np_subcomm = size/nsubcomm; 184 nleftover = size - nsubcomm*np_subcomm; 185 for (i=0; i<nsubcomm; i++){ 186 subsize[i] = np_subcomm; 187 if (i<nleftover) subsize[i]++; 188 } 189 190 /* get color and subrank of this proc */ 191 rankstart = 0; 192 for (i=0; i<nsubcomm; i++){ 193 if ( rank >= rankstart && rank < rankstart+subsize[i]) { 194 color = i; 195 subrank = rank - rankstart; 196 duprank = rank; 197 break; 198 } else { 199 rankstart += subsize[i]; 200 } 201 } 202 ierr = PetscFree(subsize);CHKERRQ(ierr); 203 204 ierr = MPI_Comm_split(comm,color,subrank,&subcomm);CHKERRQ(ierr); 205 206 /* create dupcomm with same size as comm, but its rank, duprank, maps subcomm's contiguously into dupcomm */ 207 ierr = MPI_Comm_split(comm,0,duprank,&dupcomm);CHKERRQ(ierr); 208 209 ierr = PetscCommDuplicate(dupcomm,&psubcomm->dupparent,PETSC_NULL);CHKERRQ(ierr); 210 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,PETSC_NULL);CHKERRQ(ierr); 211 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 212 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 213 psubcomm->color = color; 214 215 #if defined(PETSC_THREADCOMM_ACTIVE) 216 { 217 PetscThreadComm tcomm; 218 ierr = PetscCommGetThreadComm(comm,&tcomm);CHKERRQ(ierr); 219 ierr = MPI_Attr_put(psubcomm->dupparent,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 220 tcomm->refct++; 221 ierr = MPI_Attr_put(psubcomm->comm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 222 tcomm->refct++; 223 } 224 #endif 225 PetscFunctionReturn(0); 226 } 227 228 #undef __FUNCT__ 229 #define __FUNCT__ "PetscSubcommCreate_interlaced" 230 /* 231 Note: 232 In PCREDUNDANT, to avoid data scattering from subcomm back to original comm, we create subcommunicators 233 by iteratively taking a process into a subcommunicator. 234 Example: size=4, nsubcomm=(*psubcomm)->n=3 235 comm=(*psubcomm)->parent: 236 rank: [0] [1] [2] [3] 237 color: 0 1 2 0 238 239 subcomm=(*psubcomm)->comm: 240 subrank: [0] [0] [0] [1] 241 242 dupcomm=(*psubcomm)->dupparent: 243 duprank: [0] [2] [3] [1] 244 245 Here, subcomm[color = 0] has subsize=2, owns process [0] and [3] 246 subcomm[color = 1] has subsize=1, owns process [1] 247 subcomm[color = 2] has subsize=1, owns process [2] 248 dupcomm has same number of processes as comm, and its duprank maps 249 processes in subcomm contiguously into a 1d array: 250 duprank: [0] [1] [2] [3] 251 rank: [0] [3] [1] [2] 252 subcomm[0] subcomm[1] subcomm[2] 253 */ 254 255 PetscErrorCode PetscSubcommCreate_interlaced(PetscSubcomm psubcomm) 256 { 257 PetscErrorCode ierr; 258 PetscMPIInt rank,size,*subsize,duprank,subrank; 259 PetscInt np_subcomm,nleftover,i,j,color,nsubcomm=psubcomm->n; 260 MPI_Comm subcomm=0,dupcomm=0,comm=psubcomm->parent; 261 262 PetscFunctionBegin; 263 ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr); 264 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 265 266 /* get size of each subcommunicator */ 267 ierr = PetscMalloc((1+nsubcomm)*sizeof(PetscMPIInt),&subsize);CHKERRQ(ierr); 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 ierr = PetscCommDuplicate(dupcomm,&psubcomm->dupparent,PETSC_NULL);CHKERRQ(ierr); 295 ierr = PetscCommDuplicate(subcomm,&psubcomm->comm,PETSC_NULL);CHKERRQ(ierr); 296 ierr = MPI_Comm_free(&dupcomm);CHKERRQ(ierr); 297 ierr = MPI_Comm_free(&subcomm);CHKERRQ(ierr); 298 psubcomm->color = color; 299 300 #if defined(PETSC_THREADCOMM_ACTIVE) 301 { 302 PetscThreadComm tcomm; 303 ierr = PetscCommGetThreadComm(comm,&tcomm);CHKERRQ(ierr); 304 ierr = MPI_Attr_put(psubcomm->dupparent,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 305 tcomm->refct++; 306 ierr = MPI_Attr_put(psubcomm->comm,Petsc_ThreadComm_keyval,tcomm);CHKERRQ(ierr); 307 tcomm->refct++; 308 } 309 #endif 310 PetscFunctionReturn(0); 311 } 312 313 314